| Index: third_party/sqlite/src/pager.c
|
| ===================================================================
|
| --- third_party/sqlite/src/pager.c (revision 56608)
|
| +++ third_party/sqlite/src/pager.c (working copy)
|
| @@ -1,5450 +0,0 @@
|
| -/*
|
| -** 2001 September 15
|
| -**
|
| -** The author disclaims copyright to this source code. In place of
|
| -** a legal notice, here is a blessing:
|
| -**
|
| -** May you do good and not evil.
|
| -** May you find forgiveness for yourself and forgive others.
|
| -** May you share freely, never taking more than you give.
|
| -**
|
| -*************************************************************************
|
| -** This is the implementation of the page cache subsystem or "pager".
|
| -**
|
| -** The pager is used to access a database disk file. It implements
|
| -** atomic commit and rollback through the use of a journal file that
|
| -** is separate from the database file. The pager also implements file
|
| -** locking to prevent two processes from writing the same database
|
| -** file simultaneously, or one process from reading the database while
|
| -** another is writing.
|
| -**
|
| -** @(#) $Id: pager.c,v 1.629 2009/08/10 17:48:57 drh Exp $
|
| -*/
|
| -#ifndef SQLITE_OMIT_DISKIO
|
| -#include "sqliteInt.h"
|
| -
|
| -/*
|
| -** Macros for troubleshooting. Normally turned off
|
| -*/
|
| -#if 0
|
| -int sqlite3PagerTrace=1; /* True to enable tracing */
|
| -#define sqlite3DebugPrintf printf
|
| -#define PAGERTRACE(X) if( sqlite3PagerTrace ){ sqlite3DebugPrintf X; }
|
| -#else
|
| -#define PAGERTRACE(X)
|
| -#endif
|
| -
|
| -/*
|
| -** The following two macros are used within the PAGERTRACE() macros above
|
| -** to print out file-descriptors.
|
| -**
|
| -** PAGERID() takes a pointer to a Pager struct as its argument. The
|
| -** associated file-descriptor is returned. FILEHANDLEID() takes an sqlite3_file
|
| -** struct as its argument.
|
| -*/
|
| -#define PAGERID(p) ((int)(p->fd))
|
| -#define FILEHANDLEID(fd) ((int)fd)
|
| -
|
| -/*
|
| -** The page cache as a whole is always in one of the following
|
| -** states:
|
| -**
|
| -** PAGER_UNLOCK The page cache is not currently reading or
|
| -** writing the database file. There is no
|
| -** data held in memory. This is the initial
|
| -** state.
|
| -**
|
| -** PAGER_SHARED The page cache is reading the database.
|
| -** Writing is not permitted. There can be
|
| -** multiple readers accessing the same database
|
| -** file at the same time.
|
| -**
|
| -** PAGER_RESERVED This process has reserved the database for writing
|
| -** but has not yet made any changes. Only one process
|
| -** at a time can reserve the database. The original
|
| -** database file has not been modified so other
|
| -** processes may still be reading the on-disk
|
| -** database file.
|
| -**
|
| -** PAGER_EXCLUSIVE The page cache is writing the database.
|
| -** Access is exclusive. No other processes or
|
| -** threads can be reading or writing while one
|
| -** process is writing.
|
| -**
|
| -** PAGER_SYNCED The pager moves to this state from PAGER_EXCLUSIVE
|
| -** after all dirty pages have been written to the
|
| -** database file and the file has been synced to
|
| -** disk. All that remains to do is to remove or
|
| -** truncate the journal file and the transaction
|
| -** will be committed.
|
| -**
|
| -** The page cache comes up in PAGER_UNLOCK. The first time a
|
| -** sqlite3PagerGet() occurs, the state transitions to PAGER_SHARED.
|
| -** After all pages have been released using sqlite_page_unref(),
|
| -** the state transitions back to PAGER_UNLOCK. The first time
|
| -** that sqlite3PagerWrite() is called, the state transitions to
|
| -** PAGER_RESERVED. (Note that sqlite3PagerWrite() can only be
|
| -** called on an outstanding page which means that the pager must
|
| -** be in PAGER_SHARED before it transitions to PAGER_RESERVED.)
|
| -** PAGER_RESERVED means that there is an open rollback journal.
|
| -** The transition to PAGER_EXCLUSIVE occurs before any changes
|
| -** are made to the database file, though writes to the rollback
|
| -** journal occurs with just PAGER_RESERVED. After an sqlite3PagerRollback()
|
| -** or sqlite3PagerCommitPhaseTwo(), the state can go back to PAGER_SHARED,
|
| -** or it can stay at PAGER_EXCLUSIVE if we are in exclusive access mode.
|
| -*/
|
| -#define PAGER_UNLOCK 0
|
| -#define PAGER_SHARED 1 /* same as SHARED_LOCK */
|
| -#define PAGER_RESERVED 2 /* same as RESERVED_LOCK */
|
| -#define PAGER_EXCLUSIVE 4 /* same as EXCLUSIVE_LOCK */
|
| -#define PAGER_SYNCED 5
|
| -
|
| -/*
|
| -** A macro used for invoking the codec if there is one
|
| -*/
|
| -#ifdef SQLITE_HAS_CODEC
|
| -# define CODEC1(P,D,N,X,E) \
|
| - if( P->xCodec && P->xCodec(P->pCodec,D,N,X)==0 ){ E; }
|
| -# define CODEC2(P,D,N,X,E,O) \
|
| - if( P->xCodec==0 ){ O=(char*)D; }else \
|
| - if( (O=(char*)(P->xCodec(P->pCodec,D,N,X)))==0 ){ E; }
|
| -#else
|
| -# define CODEC1(P,D,N,X,E) /* NO-OP */
|
| -# define CODEC2(P,D,N,X,E,O) O=(char*)D
|
| -#endif
|
| -
|
| -/*
|
| -** The maximum allowed sector size. 64KiB. If the xSectorsize() method
|
| -** returns a value larger than this, then MAX_SECTOR_SIZE is used instead.
|
| -** This could conceivably cause corruption following a power failure on
|
| -** such a system. This is currently an undocumented limit.
|
| -*/
|
| -#define MAX_SECTOR_SIZE 0x10000
|
| -
|
| -/*
|
| -** An instance of the following structure is allocated for each active
|
| -** savepoint and statement transaction in the system. All such structures
|
| -** are stored in the Pager.aSavepoint[] array, which is allocated and
|
| -** resized using sqlite3Realloc().
|
| -**
|
| -** When a savepoint is created, the PagerSavepoint.iHdrOffset field is
|
| -** set to 0. If a journal-header is written into the main journal while
|
| -** the savepoint is active, then iHdrOffset is set to the byte offset
|
| -** immediately following the last journal record written into the main
|
| -** journal before the journal-header. This is required during savepoint
|
| -** rollback (see pagerPlaybackSavepoint()).
|
| -*/
|
| -typedef struct PagerSavepoint PagerSavepoint;
|
| -struct PagerSavepoint {
|
| - i64 iOffset; /* Starting offset in main journal */
|
| - i64 iHdrOffset; /* See above */
|
| - Bitvec *pInSavepoint; /* Set of pages in this savepoint */
|
| - Pgno nOrig; /* Original number of pages in file */
|
| - Pgno iSubRec; /* Index of first record in sub-journal */
|
| -};
|
| -
|
| -/*
|
| -** A open page cache is an instance of the following structure.
|
| -**
|
| -** errCode
|
| -**
|
| -** Pager.errCode may be set to SQLITE_IOERR, SQLITE_CORRUPT, or
|
| -** or SQLITE_FULL. Once one of the first three errors occurs, it persists
|
| -** and is returned as the result of every major pager API call. The
|
| -** SQLITE_FULL return code is slightly different. It persists only until the
|
| -** next successful rollback is performed on the pager cache. Also,
|
| -** SQLITE_FULL does not affect the sqlite3PagerGet() and sqlite3PagerLookup()
|
| -** APIs, they may still be used successfully.
|
| -**
|
| -** dbSizeValid, dbSize, dbOrigSize, dbFileSize
|
| -**
|
| -** Managing the size of the database file in pages is a little complicated.
|
| -** The variable Pager.dbSize contains the number of pages that the database
|
| -** image currently contains. As the database image grows or shrinks this
|
| -** variable is updated. The variable Pager.dbFileSize contains the number
|
| -** of pages in the database file. This may be different from Pager.dbSize
|
| -** if some pages have been appended to the database image but not yet written
|
| -** out from the cache to the actual file on disk. Or if the image has been
|
| -** truncated by an incremental-vacuum operation. The Pager.dbOrigSize variable
|
| -** contains the number of pages in the database image when the current
|
| -** transaction was opened. The contents of all three of these variables is
|
| -** only guaranteed to be correct if the boolean Pager.dbSizeValid is true.
|
| -**
|
| -** TODO: Under what conditions is dbSizeValid set? Cleared?
|
| -**
|
| -** changeCountDone
|
| -**
|
| -** This boolean variable is used to make sure that the change-counter
|
| -** (the 4-byte header field at byte offset 24 of the database file) is
|
| -** not updated more often than necessary.
|
| -**
|
| -** It is set to true when the change-counter field is updated, which
|
| -** can only happen if an exclusive lock is held on the database file.
|
| -** It is cleared (set to false) whenever an exclusive lock is
|
| -** relinquished on the database file. Each time a transaction is committed,
|
| -** The changeCountDone flag is inspected. If it is true, the work of
|
| -** updating the change-counter is omitted for the current transaction.
|
| -**
|
| -** This mechanism means that when running in exclusive mode, a connection
|
| -** need only update the change-counter once, for the first transaction
|
| -** committed.
|
| -**
|
| -** dbModified
|
| -**
|
| -** The dbModified flag is set whenever a database page is dirtied.
|
| -** It is cleared at the end of each transaction.
|
| -**
|
| -** It is used when committing or otherwise ending a transaction. If
|
| -** the dbModified flag is clear then less work has to be done.
|
| -**
|
| -** journalStarted
|
| -**
|
| -** This flag is set whenever the the main journal is synced.
|
| -**
|
| -** The point of this flag is that it must be set after the
|
| -** first journal header in a journal file has been synced to disk.
|
| -** After this has happened, new pages appended to the database
|
| -** do not need the PGHDR_NEED_SYNC flag set, as they do not need
|
| -** to wait for a journal sync before they can be written out to
|
| -** the database file (see function pager_write()).
|
| -**
|
| -** setMaster
|
| -**
|
| -** This variable is used to ensure that the master journal file name
|
| -** (if any) is only written into the journal file once.
|
| -**
|
| -** When committing a transaction, the master journal file name (if any)
|
| -** may be written into the journal file while the pager is still in
|
| -** PAGER_RESERVED state (see CommitPhaseOne() for the action). It
|
| -** then attempts to upgrade to an exclusive lock. If this attempt
|
| -** fails, then SQLITE_BUSY may be returned to the user and the user
|
| -** may attempt to commit the transaction again later (calling
|
| -** CommitPhaseOne() again). This flag is used to ensure that the
|
| -** master journal name is only written to the journal file the first
|
| -** time CommitPhaseOne() is called.
|
| -**
|
| -** doNotSync
|
| -**
|
| -** This variable is set and cleared by sqlite3PagerWrite().
|
| -**
|
| -** needSync
|
| -**
|
| -** TODO: It might be easier to set this variable in writeJournalHdr()
|
| -** and writeMasterJournal() only. Change its meaning to "unsynced data
|
| -** has been written to the journal".
|
| -**
|
| -** subjInMemory
|
| -**
|
| -** This is a boolean variable. If true, then any required sub-journal
|
| -** is opened as an in-memory journal file. If false, then in-memory
|
| -** sub-journals are only used for in-memory pager files.
|
| -*/
|
| -struct Pager {
|
| - sqlite3_vfs *pVfs; /* OS functions to use for IO */
|
| - u8 exclusiveMode; /* Boolean. True if locking_mode==EXCLUSIVE */
|
| - u8 journalMode; /* On of the PAGER_JOURNALMODE_* values */
|
| - u8 useJournal; /* Use a rollback journal on this file */
|
| - u8 noReadlock; /* Do not bother to obtain readlocks */
|
| - u8 noSync; /* Do not sync the journal if true */
|
| - u8 fullSync; /* Do extra syncs of the journal for robustness */
|
| - u8 sync_flags; /* One of SYNC_NORMAL or SYNC_FULL */
|
| - u8 tempFile; /* zFilename is a temporary file */
|
| - u8 readOnly; /* True for a read-only database */
|
| - u8 memDb; /* True to inhibit all file I/O */
|
| -
|
| - /* The following block contains those class members that are dynamically
|
| - ** modified during normal operations. The other variables in this structure
|
| - ** are either constant throughout the lifetime of the pager, or else
|
| - ** used to store configuration parameters that affect the way the pager
|
| - ** operates.
|
| - **
|
| - ** The 'state' variable is described in more detail along with the
|
| - ** descriptions of the values it may take - PAGER_UNLOCK etc. Many of the
|
| - ** other variables in this block are described in the comment directly
|
| - ** above this class definition.
|
| - */
|
| - u8 state; /* PAGER_UNLOCK, _SHARED, _RESERVED, etc. */
|
| - u8 dbModified; /* True if there are any changes to the Db */
|
| - u8 needSync; /* True if an fsync() is needed on the journal */
|
| - u8 journalStarted; /* True if header of journal is synced */
|
| - u8 changeCountDone; /* Set after incrementing the change-counter */
|
| - u8 setMaster; /* True if a m-j name has been written to jrnl */
|
| - u8 doNotSync; /* Boolean. While true, do not spill the cache */
|
| - u8 dbSizeValid; /* Set when dbSize is correct */
|
| - u8 subjInMemory; /* True to use in-memory sub-journals */
|
| - Pgno dbSize; /* Number of pages in the database */
|
| - Pgno dbOrigSize; /* dbSize before the current transaction */
|
| - Pgno dbFileSize; /* Number of pages in the database file */
|
| - int errCode; /* One of several kinds of errors */
|
| - int nRec; /* Pages journalled since last j-header written */
|
| - u32 cksumInit; /* Quasi-random value added to every checksum */
|
| - u32 nSubRec; /* Number of records written to sub-journal */
|
| - Bitvec *pInJournal; /* One bit for each page in the database file */
|
| - sqlite3_file *fd; /* File descriptor for database */
|
| - sqlite3_file *jfd; /* File descriptor for main journal */
|
| - sqlite3_file *sjfd; /* File descriptor for sub-journal */
|
| - i64 journalOff; /* Current write offset in the journal file */
|
| - i64 journalHdr; /* Byte offset to previous journal header */
|
| - PagerSavepoint *aSavepoint; /* Array of active savepoints */
|
| - int nSavepoint; /* Number of elements in aSavepoint[] */
|
| - char dbFileVers[16]; /* Changes whenever database file changes */
|
| - u32 sectorSize; /* Assumed sector size during rollback */
|
| -
|
| - u16 nExtra; /* Add this many bytes to each in-memory page */
|
| - i16 nReserve; /* Number of unused bytes at end of each page */
|
| - u32 vfsFlags; /* Flags for sqlite3_vfs.xOpen() */
|
| - int pageSize; /* Number of bytes in a page */
|
| - Pgno mxPgno; /* Maximum allowed size of the database */
|
| - char *zFilename; /* Name of the database file */
|
| - char *zJournal; /* Name of the journal file */
|
| - int (*xBusyHandler)(void*); /* Function to call when busy */
|
| - void *pBusyHandlerArg; /* Context argument for xBusyHandler */
|
| -#ifdef SQLITE_TEST
|
| - int nHit, nMiss; /* Cache hits and missing */
|
| - int nRead, nWrite; /* Database pages read/written */
|
| -#endif
|
| - void (*xReiniter)(DbPage*); /* Call this routine when reloading pages */
|
| -#ifdef SQLITE_HAS_CODEC
|
| - void *(*xCodec)(void*,void*,Pgno,int); /* Routine for en/decoding data */
|
| - void (*xCodecSizeChng)(void*,int,int); /* Notify of page size changes */
|
| - void (*xCodecFree)(void*); /* Destructor for the codec */
|
| - void *pCodec; /* First argument to xCodec... methods */
|
| -#endif
|
| - char *pTmpSpace; /* Pager.pageSize bytes of space for tmp use */
|
| - i64 journalSizeLimit; /* Size limit for persistent journal files */
|
| - PCache *pPCache; /* Pointer to page cache object */
|
| - sqlite3_backup *pBackup; /* Pointer to list of ongoing backup processes */
|
| -};
|
| -
|
| -/*
|
| -** The following global variables hold counters used for
|
| -** testing purposes only. These variables do not exist in
|
| -** a non-testing build. These variables are not thread-safe.
|
| -*/
|
| -#ifdef SQLITE_TEST
|
| -int sqlite3_pager_readdb_count = 0; /* Number of full pages read from DB */
|
| -int sqlite3_pager_writedb_count = 0; /* Number of full pages written to DB */
|
| -int sqlite3_pager_writej_count = 0; /* Number of pages written to journal */
|
| -# define PAGER_INCR(v) v++
|
| -#else
|
| -# define PAGER_INCR(v)
|
| -#endif
|
| -
|
| -
|
| -
|
| -/*
|
| -** Journal files begin with the following magic string. The data
|
| -** was obtained from /dev/random. It is used only as a sanity check.
|
| -**
|
| -** Since version 2.8.0, the journal format contains additional sanity
|
| -** checking information. If the power fails while the journal is being
|
| -** written, semi-random garbage data might appear in the journal
|
| -** file after power is restored. If an attempt is then made
|
| -** to roll the journal back, the database could be corrupted. The additional
|
| -** sanity checking data is an attempt to discover the garbage in the
|
| -** journal and ignore it.
|
| -**
|
| -** The sanity checking information for the new journal format consists
|
| -** of a 32-bit checksum on each page of data. The checksum covers both
|
| -** the page number and the pPager->pageSize bytes of data for the page.
|
| -** This cksum is initialized to a 32-bit random value that appears in the
|
| -** journal file right after the header. The random initializer is important,
|
| -** because garbage data that appears at the end of a journal is likely
|
| -** data that was once in other files that have now been deleted. If the
|
| -** garbage data came from an obsolete journal file, the checksums might
|
| -** be correct. But by initializing the checksum to random value which
|
| -** is different for every journal, we minimize that risk.
|
| -*/
|
| -static const unsigned char aJournalMagic[] = {
|
| - 0xd9, 0xd5, 0x05, 0xf9, 0x20, 0xa1, 0x63, 0xd7,
|
| -};
|
| -
|
| -/*
|
| -** The size of the of each page record in the journal is given by
|
| -** the following macro.
|
| -*/
|
| -#define JOURNAL_PG_SZ(pPager) ((pPager->pageSize) + 8)
|
| -
|
| -/*
|
| -** The journal header size for this pager. This is usually the same
|
| -** size as a single disk sector. See also setSectorSize().
|
| -*/
|
| -#define JOURNAL_HDR_SZ(pPager) (pPager->sectorSize)
|
| -
|
| -/*
|
| -** The macro MEMDB is true if we are dealing with an in-memory database.
|
| -** We do this as a macro so that if the SQLITE_OMIT_MEMORYDB macro is set,
|
| -** the value of MEMDB will be a constant and the compiler will optimize
|
| -** out code that would never execute.
|
| -*/
|
| -#ifdef SQLITE_OMIT_MEMORYDB
|
| -# define MEMDB 0
|
| -#else
|
| -# define MEMDB pPager->memDb
|
| -#endif
|
| -
|
| -/*
|
| -** The maximum legal page number is (2^31 - 1).
|
| -*/
|
| -#define PAGER_MAX_PGNO 2147483647
|
| -
|
| -/* Begin preload-cache.patch for Chromium */
|
| -/* See comments above the definition. */
|
| -int sqlite3PagerAcquire2(
|
| - Pager *pPager,
|
| - Pgno pgno,
|
| - DbPage **ppPage,
|
| - int noContent,
|
| - unsigned char *pDataToFill);
|
| -/* End preload-cache.patch for Chromium */
|
| -
|
| -#ifndef NDEBUG
|
| -/*
|
| -** Usage:
|
| -**
|
| -** assert( assert_pager_state(pPager) );
|
| -*/
|
| -static int assert_pager_state(Pager *pPager){
|
| -
|
| - /* A temp-file is always in PAGER_EXCLUSIVE or PAGER_SYNCED state. */
|
| - assert( pPager->tempFile==0 || pPager->state>=PAGER_EXCLUSIVE );
|
| -
|
| - /* The changeCountDone flag is always set for temp-files */
|
| - assert( pPager->tempFile==0 || pPager->changeCountDone );
|
| -
|
| - return 1;
|
| -}
|
| -#endif
|
| -
|
| -/*
|
| -** Return true if it is necessary to write page *pPg into the sub-journal.
|
| -** A page needs to be written into the sub-journal if there exists one
|
| -** or more open savepoints for which:
|
| -**
|
| -** * The page-number is less than or equal to PagerSavepoint.nOrig, and
|
| -** * The bit corresponding to the page-number is not set in
|
| -** PagerSavepoint.pInSavepoint.
|
| -*/
|
| -static int subjRequiresPage(PgHdr *pPg){
|
| - Pgno pgno = pPg->pgno;
|
| - Pager *pPager = pPg->pPager;
|
| - int i;
|
| - for(i=0; i<pPager->nSavepoint; i++){
|
| - PagerSavepoint *p = &pPager->aSavepoint[i];
|
| - if( p->nOrig>=pgno && 0==sqlite3BitvecTest(p->pInSavepoint, pgno) ){
|
| - return 1;
|
| - }
|
| - }
|
| - return 0;
|
| -}
|
| -
|
| -/*
|
| -** Return true if the page is already in the journal file.
|
| -*/
|
| -static int pageInJournal(PgHdr *pPg){
|
| - return sqlite3BitvecTest(pPg->pPager->pInJournal, pPg->pgno);
|
| -}
|
| -
|
| -/*
|
| -** Read a 32-bit integer from the given file descriptor. Store the integer
|
| -** that is read in *pRes. Return SQLITE_OK if everything worked, or an
|
| -** error code is something goes wrong.
|
| -**
|
| -** All values are stored on disk as big-endian.
|
| -*/
|
| -static int read32bits(sqlite3_file *fd, i64 offset, u32 *pRes){
|
| - unsigned char ac[4];
|
| - int rc = sqlite3OsRead(fd, ac, sizeof(ac), offset);
|
| - if( rc==SQLITE_OK ){
|
| - *pRes = sqlite3Get4byte(ac);
|
| - }
|
| - return rc;
|
| -}
|
| -
|
| -/*
|
| -** Write a 32-bit integer into a string buffer in big-endian byte order.
|
| -*/
|
| -#define put32bits(A,B) sqlite3Put4byte((u8*)A,B)
|
| -
|
| -/*
|
| -** Write a 32-bit integer into the given file descriptor. Return SQLITE_OK
|
| -** on success or an error code is something goes wrong.
|
| -*/
|
| -static int write32bits(sqlite3_file *fd, i64 offset, u32 val){
|
| - char ac[4];
|
| - put32bits(ac, val);
|
| - return sqlite3OsWrite(fd, ac, 4, offset);
|
| -}
|
| -
|
| -/*
|
| -** The argument to this macro is a file descriptor (type sqlite3_file*).
|
| -** Return 0 if it is not open, or non-zero (but not 1) if it is.
|
| -**
|
| -** This is so that expressions can be written as:
|
| -**
|
| -** if( isOpen(pPager->jfd) ){ ...
|
| -**
|
| -** instead of
|
| -**
|
| -** if( pPager->jfd->pMethods ){ ...
|
| -*/
|
| -#define isOpen(pFd) ((pFd)->pMethods)
|
| -
|
| -/*
|
| -** If file pFd is open, call sqlite3OsUnlock() on it.
|
| -*/
|
| -static int osUnlock(sqlite3_file *pFd, int eLock){
|
| - if( !isOpen(pFd) ){
|
| - return SQLITE_OK;
|
| - }
|
| - return sqlite3OsUnlock(pFd, eLock);
|
| -}
|
| -
|
| -/*
|
| -** This function determines whether or not the atomic-write optimization
|
| -** can be used with this pager. The optimization can be used if:
|
| -**
|
| -** (a) the value returned by OsDeviceCharacteristics() indicates that
|
| -** a database page may be written atomically, and
|
| -** (b) the value returned by OsSectorSize() is less than or equal
|
| -** to the page size.
|
| -**
|
| -** The optimization is also always enabled for temporary files. It is
|
| -** an error to call this function if pPager is opened on an in-memory
|
| -** database.
|
| -**
|
| -** If the optimization cannot be used, 0 is returned. If it can be used,
|
| -** then the value returned is the size of the journal file when it
|
| -** contains rollback data for exactly one page.
|
| -*/
|
| -#ifdef SQLITE_ENABLE_ATOMIC_WRITE
|
| -static int jrnlBufferSize(Pager *pPager){
|
| - assert( !MEMDB );
|
| - if( !pPager->tempFile ){
|
| - int dc; /* Device characteristics */
|
| - int nSector; /* Sector size */
|
| - int szPage; /* Page size */
|
| -
|
| - assert( isOpen(pPager->fd) );
|
| - dc = sqlite3OsDeviceCharacteristics(pPager->fd);
|
| - nSector = pPager->sectorSize;
|
| - szPage = pPager->pageSize;
|
| -
|
| - assert(SQLITE_IOCAP_ATOMIC512==(512>>8));
|
| - assert(SQLITE_IOCAP_ATOMIC64K==(65536>>8));
|
| - if( 0==(dc&(SQLITE_IOCAP_ATOMIC|(szPage>>8)) || nSector>szPage) ){
|
| - return 0;
|
| - }
|
| - }
|
| -
|
| - return JOURNAL_HDR_SZ(pPager) + JOURNAL_PG_SZ(pPager);
|
| -}
|
| -#endif
|
| -
|
| -/*
|
| -** If SQLITE_CHECK_PAGES is defined then we do some sanity checking
|
| -** on the cache using a hash function. This is used for testing
|
| -** and debugging only.
|
| -*/
|
| -#ifdef SQLITE_CHECK_PAGES
|
| -/*
|
| -** Return a 32-bit hash of the page data for pPage.
|
| -*/
|
| -static u32 pager_datahash(int nByte, unsigned char *pData){
|
| - u32 hash = 0;
|
| - int i;
|
| - for(i=0; i<nByte; i++){
|
| - hash = (hash*1039) + pData[i];
|
| - }
|
| - return hash;
|
| -}
|
| -static u32 pager_pagehash(PgHdr *pPage){
|
| - return pager_datahash(pPage->pPager->pageSize, (unsigned char *)pPage->pData);
|
| -}
|
| -static void pager_set_pagehash(PgHdr *pPage){
|
| - pPage->pageHash = pager_pagehash(pPage);
|
| -}
|
| -
|
| -/*
|
| -** The CHECK_PAGE macro takes a PgHdr* as an argument. If SQLITE_CHECK_PAGES
|
| -** is defined, and NDEBUG is not defined, an assert() statement checks
|
| -** that the page is either dirty or still matches the calculated page-hash.
|
| -*/
|
| -#define CHECK_PAGE(x) checkPage(x)
|
| -static void checkPage(PgHdr *pPg){
|
| - Pager *pPager = pPg->pPager;
|
| - assert( !pPg->pageHash || pPager->errCode
|
| - || (pPg->flags&PGHDR_DIRTY) || pPg->pageHash==pager_pagehash(pPg) );
|
| -}
|
| -
|
| -#else
|
| -#define pager_datahash(X,Y) 0
|
| -#define pager_pagehash(X) 0
|
| -#define CHECK_PAGE(x)
|
| -#endif /* SQLITE_CHECK_PAGES */
|
| -
|
| -/*
|
| -** When this is called the journal file for pager pPager must be open.
|
| -** This function attempts to read a master journal file name from the
|
| -** end of the file and, if successful, copies it into memory supplied
|
| -** by the caller. See comments above writeMasterJournal() for the format
|
| -** used to store a master journal file name at the end of a journal file.
|
| -**
|
| -** zMaster must point to a buffer of at least nMaster bytes allocated by
|
| -** the caller. This should be sqlite3_vfs.mxPathname+1 (to ensure there is
|
| -** enough space to write the master journal name). If the master journal
|
| -** name in the journal is longer than nMaster bytes (including a
|
| -** nul-terminator), then this is handled as if no master journal name
|
| -** were present in the journal.
|
| -**
|
| -** If a master journal file name is present at the end of the journal
|
| -** file, then it is copied into the buffer pointed to by zMaster. A
|
| -** nul-terminator byte is appended to the buffer following the master
|
| -** journal file name.
|
| -**
|
| -** If it is determined that no master journal file name is present
|
| -** zMaster[0] is set to 0 and SQLITE_OK returned.
|
| -**
|
| -** If an error occurs while reading from the journal file, an SQLite
|
| -** error code is returned.
|
| -*/
|
| -static int readMasterJournal(sqlite3_file *pJrnl, char *zMaster, u32 nMaster){
|
| - int rc; /* Return code */
|
| - u32 len; /* Length in bytes of master journal name */
|
| - i64 szJ; /* Total size in bytes of journal file pJrnl */
|
| - u32 cksum; /* MJ checksum value read from journal */
|
| - u32 u; /* Unsigned loop counter */
|
| - unsigned char aMagic[8]; /* A buffer to hold the magic header */
|
| - zMaster[0] = '\0';
|
| -
|
| - if( SQLITE_OK!=(rc = sqlite3OsFileSize(pJrnl, &szJ))
|
| - || szJ<16
|
| - || SQLITE_OK!=(rc = read32bits(pJrnl, szJ-16, &len))
|
| - || len>=nMaster
|
| - || SQLITE_OK!=(rc = read32bits(pJrnl, szJ-12, &cksum))
|
| - || SQLITE_OK!=(rc = sqlite3OsRead(pJrnl, aMagic, 8, szJ-8))
|
| - || memcmp(aMagic, aJournalMagic, 8)
|
| - || SQLITE_OK!=(rc = sqlite3OsRead(pJrnl, zMaster, len, szJ-16-len))
|
| - ){
|
| - return rc;
|
| - }
|
| -
|
| - /* See if the checksum matches the master journal name */
|
| - for(u=0; u<len; u++){
|
| - cksum -= zMaster[u];
|
| - }
|
| - if( cksum ){
|
| - /* If the checksum doesn't add up, then one or more of the disk sectors
|
| - ** containing the master journal filename is corrupted. This means
|
| - ** definitely roll back, so just return SQLITE_OK and report a (nul)
|
| - ** master-journal filename.
|
| - */
|
| - len = 0;
|
| - }
|
| - zMaster[len] = '\0';
|
| -
|
| - return SQLITE_OK;
|
| -}
|
| -
|
| -/*
|
| -** Return the offset of the sector boundary at or immediately
|
| -** following the value in pPager->journalOff, assuming a sector
|
| -** size of pPager->sectorSize bytes.
|
| -**
|
| -** i.e for a sector size of 512:
|
| -**
|
| -** Pager.journalOff Return value
|
| -** ---------------------------------------
|
| -** 0 0
|
| -** 512 512
|
| -** 100 512
|
| -** 2000 2048
|
| -**
|
| -*/
|
| -static i64 journalHdrOffset(Pager *pPager){
|
| - i64 offset = 0;
|
| - i64 c = pPager->journalOff;
|
| - if( c ){
|
| - offset = ((c-1)/JOURNAL_HDR_SZ(pPager) + 1) * JOURNAL_HDR_SZ(pPager);
|
| - }
|
| - assert( offset%JOURNAL_HDR_SZ(pPager)==0 );
|
| - assert( offset>=c );
|
| - assert( (offset-c)<JOURNAL_HDR_SZ(pPager) );
|
| - return offset;
|
| -}
|
| -
|
| -/*
|
| -** The journal file must be open when this function is called.
|
| -**
|
| -** This function is a no-op if the journal file has not been written to
|
| -** within the current transaction (i.e. if Pager.journalOff==0).
|
| -**
|
| -** If doTruncate is non-zero or the Pager.journalSizeLimit variable is
|
| -** set to 0, then truncate the journal file to zero bytes in size. Otherwise,
|
| -** zero the 28-byte header at the start of the journal file. In either case,
|
| -** if the pager is not in no-sync mode, sync the journal file immediately
|
| -** after writing or truncating it.
|
| -**
|
| -** If Pager.journalSizeLimit is set to a positive, non-zero value, and
|
| -** following the truncation or zeroing described above the size of the
|
| -** journal file in bytes is larger than this value, then truncate the
|
| -** journal file to Pager.journalSizeLimit bytes. The journal file does
|
| -** not need to be synced following this operation.
|
| -**
|
| -** If an IO error occurs, abandon processing and return the IO error code.
|
| -** Otherwise, return SQLITE_OK.
|
| -*/
|
| -static int zeroJournalHdr(Pager *pPager, int doTruncate){
|
| - int rc = SQLITE_OK; /* Return code */
|
| - assert( isOpen(pPager->jfd) );
|
| - if( pPager->journalOff ){
|
| - const i64 iLimit = pPager->journalSizeLimit; /* Local cache of jsl */
|
| -
|
| - IOTRACE(("JZEROHDR %p\n", pPager))
|
| - if( doTruncate || iLimit==0 ){
|
| - rc = sqlite3OsTruncate(pPager->jfd, 0);
|
| - }else{
|
| - static const char zeroHdr[28] = {0};
|
| - rc = sqlite3OsWrite(pPager->jfd, zeroHdr, sizeof(zeroHdr), 0);
|
| - }
|
| - if( rc==SQLITE_OK && !pPager->noSync ){
|
| - rc = sqlite3OsSync(pPager->jfd, SQLITE_SYNC_DATAONLY|pPager->sync_flags);
|
| - }
|
| -
|
| - /* At this point the transaction is committed but the write lock
|
| - ** is still held on the file. If there is a size limit configured for
|
| - ** the persistent journal and the journal file currently consumes more
|
| - ** space than that limit allows for, truncate it now. There is no need
|
| - ** to sync the file following this operation.
|
| - */
|
| - if( rc==SQLITE_OK && iLimit>0 ){
|
| - i64 sz;
|
| - rc = sqlite3OsFileSize(pPager->jfd, &sz);
|
| - if( rc==SQLITE_OK && sz>iLimit ){
|
| - rc = sqlite3OsTruncate(pPager->jfd, iLimit);
|
| - }
|
| - }
|
| - }
|
| - return rc;
|
| -}
|
| -
|
| -/*
|
| -** The journal file must be open when this routine is called. A journal
|
| -** header (JOURNAL_HDR_SZ bytes) is written into the journal file at the
|
| -** current location.
|
| -**
|
| -** The format for the journal header is as follows:
|
| -** - 8 bytes: Magic identifying journal format.
|
| -** - 4 bytes: Number of records in journal, or -1 no-sync mode is on.
|
| -** - 4 bytes: Random number used for page hash.
|
| -** - 4 bytes: Initial database page count.
|
| -** - 4 bytes: Sector size used by the process that wrote this journal.
|
| -** - 4 bytes: Database page size.
|
| -**
|
| -** Followed by (JOURNAL_HDR_SZ - 28) bytes of unused space.
|
| -*/
|
| -static int writeJournalHdr(Pager *pPager){
|
| - int rc = SQLITE_OK; /* Return code */
|
| - char *zHeader = pPager->pTmpSpace; /* Temporary space used to build header */
|
| - u32 nHeader = pPager->pageSize; /* Size of buffer pointed to by zHeader */
|
| - u32 nWrite; /* Bytes of header sector written */
|
| - int ii; /* Loop counter */
|
| -
|
| - assert( isOpen(pPager->jfd) ); /* Journal file must be open. */
|
| -
|
| - if( nHeader>JOURNAL_HDR_SZ(pPager) ){
|
| - nHeader = JOURNAL_HDR_SZ(pPager);
|
| - }
|
| -
|
| - /* If there are active savepoints and any of them were created
|
| - ** since the most recent journal header was written, update the
|
| - ** PagerSavepoint.iHdrOffset fields now.
|
| - */
|
| - for(ii=0; ii<pPager->nSavepoint; ii++){
|
| - if( pPager->aSavepoint[ii].iHdrOffset==0 ){
|
| - pPager->aSavepoint[ii].iHdrOffset = pPager->journalOff;
|
| - }
|
| - }
|
| -
|
| - pPager->journalHdr = pPager->journalOff = journalHdrOffset(pPager);
|
| -
|
| - /*
|
| - ** Write the nRec Field - the number of page records that follow this
|
| - ** journal header. Normally, zero is written to this value at this time.
|
| - ** After the records are added to the journal (and the journal synced,
|
| - ** if in full-sync mode), the zero is overwritten with the true number
|
| - ** of records (see syncJournal()).
|
| - **
|
| - ** A faster alternative is to write 0xFFFFFFFF to the nRec field. When
|
| - ** reading the journal this value tells SQLite to assume that the
|
| - ** rest of the journal file contains valid page records. This assumption
|
| - ** is dangerous, as if a failure occurred whilst writing to the journal
|
| - ** file it may contain some garbage data. There are two scenarios
|
| - ** where this risk can be ignored:
|
| - **
|
| - ** * When the pager is in no-sync mode. Corruption can follow a
|
| - ** power failure in this case anyway.
|
| - **
|
| - ** * When the SQLITE_IOCAP_SAFE_APPEND flag is set. This guarantees
|
| - ** that garbage data is never appended to the journal file.
|
| - */
|
| - assert( isOpen(pPager->fd) || pPager->noSync );
|
| - if( (pPager->noSync) || (pPager->journalMode==PAGER_JOURNALMODE_MEMORY)
|
| - || (sqlite3OsDeviceCharacteristics(pPager->fd)&SQLITE_IOCAP_SAFE_APPEND)
|
| - ){
|
| - memcpy(zHeader, aJournalMagic, sizeof(aJournalMagic));
|
| - put32bits(&zHeader[sizeof(aJournalMagic)], 0xffffffff);
|
| - }else{
|
| - memset(zHeader, 0, sizeof(aJournalMagic)+4);
|
| - }
|
| -
|
| - /* The random check-hash initialiser */
|
| - sqlite3_randomness(sizeof(pPager->cksumInit), &pPager->cksumInit);
|
| - put32bits(&zHeader[sizeof(aJournalMagic)+4], pPager->cksumInit);
|
| - /* The initial database size */
|
| - put32bits(&zHeader[sizeof(aJournalMagic)+8], pPager->dbOrigSize);
|
| - /* The assumed sector size for this process */
|
| - put32bits(&zHeader[sizeof(aJournalMagic)+12], pPager->sectorSize);
|
| -
|
| - /* The page size */
|
| - put32bits(&zHeader[sizeof(aJournalMagic)+16], pPager->pageSize);
|
| -
|
| - /* Initializing the tail of the buffer is not necessary. Everything
|
| - ** works find if the following memset() is omitted. But initializing
|
| - ** the memory prevents valgrind from complaining, so we are willing to
|
| - ** take the performance hit.
|
| - */
|
| - memset(&zHeader[sizeof(aJournalMagic)+20], 0,
|
| - nHeader-(sizeof(aJournalMagic)+20));
|
| -
|
| - /* In theory, it is only necessary to write the 28 bytes that the
|
| - ** journal header consumes to the journal file here. Then increment the
|
| - ** Pager.journalOff variable by JOURNAL_HDR_SZ so that the next
|
| - ** record is written to the following sector (leaving a gap in the file
|
| - ** that will be implicitly filled in by the OS).
|
| - **
|
| - ** However it has been discovered that on some systems this pattern can
|
| - ** be significantly slower than contiguously writing data to the file,
|
| - ** even if that means explicitly writing data to the block of
|
| - ** (JOURNAL_HDR_SZ - 28) bytes that will not be used. So that is what
|
| - ** is done.
|
| - **
|
| - ** The loop is required here in case the sector-size is larger than the
|
| - ** database page size. Since the zHeader buffer is only Pager.pageSize
|
| - ** bytes in size, more than one call to sqlite3OsWrite() may be required
|
| - ** to populate the entire journal header sector.
|
| - */
|
| - for(nWrite=0; rc==SQLITE_OK&&nWrite<JOURNAL_HDR_SZ(pPager); nWrite+=nHeader){
|
| - IOTRACE(("JHDR %p %lld %d\n", pPager, pPager->journalHdr, nHeader))
|
| - rc = sqlite3OsWrite(pPager->jfd, zHeader, nHeader, pPager->journalOff);
|
| - pPager->journalOff += nHeader;
|
| - }
|
| -
|
| - return rc;
|
| -}
|
| -
|
| -/*
|
| -** The journal file must be open when this is called. A journal header file
|
| -** (JOURNAL_HDR_SZ bytes) is read from the current location in the journal
|
| -** file. The current location in the journal file is given by
|
| -** pPager->journalOff. See comments above function writeJournalHdr() for
|
| -** a description of the journal header format.
|
| -**
|
| -** If the header is read successfully, *pNRec is set to the number of
|
| -** page records following this header and *pDbSize is set to the size of the
|
| -** database before the transaction began, in pages. Also, pPager->cksumInit
|
| -** is set to the value read from the journal header. SQLITE_OK is returned
|
| -** in this case.
|
| -**
|
| -** If the journal header file appears to be corrupted, SQLITE_DONE is
|
| -** returned and *pNRec and *PDbSize are undefined. If JOURNAL_HDR_SZ bytes
|
| -** cannot be read from the journal file an error code is returned.
|
| -*/
|
| -static int readJournalHdr(
|
| - Pager *pPager, /* Pager object */
|
| - int isHot,
|
| - i64 journalSize, /* Size of the open journal file in bytes */
|
| - u32 *pNRec, /* OUT: Value read from the nRec field */
|
| - u32 *pDbSize /* OUT: Value of original database size field */
|
| -){
|
| - int rc; /* Return code */
|
| - unsigned char aMagic[8]; /* A buffer to hold the magic header */
|
| - i64 iHdrOff; /* Offset of journal header being read */
|
| -
|
| - assert( isOpen(pPager->jfd) ); /* Journal file must be open. */
|
| -
|
| - /* Advance Pager.journalOff to the start of the next sector. If the
|
| - ** journal file is too small for there to be a header stored at this
|
| - ** point, return SQLITE_DONE.
|
| - */
|
| - pPager->journalOff = journalHdrOffset(pPager);
|
| - if( pPager->journalOff+JOURNAL_HDR_SZ(pPager) > journalSize ){
|
| - return SQLITE_DONE;
|
| - }
|
| - iHdrOff = pPager->journalOff;
|
| -
|
| - /* Read in the first 8 bytes of the journal header. If they do not match
|
| - ** the magic string found at the start of each journal header, return
|
| - ** SQLITE_DONE. If an IO error occurs, return an error code. Otherwise,
|
| - ** proceed.
|
| - */
|
| - if( isHot || iHdrOff!=pPager->journalHdr ){
|
| - rc = sqlite3OsRead(pPager->jfd, aMagic, sizeof(aMagic), iHdrOff);
|
| - if( rc ){
|
| - return rc;
|
| - }
|
| - if( memcmp(aMagic, aJournalMagic, sizeof(aMagic))!=0 ){
|
| - return SQLITE_DONE;
|
| - }
|
| - }
|
| -
|
| - /* Read the first three 32-bit fields of the journal header: The nRec
|
| - ** field, the checksum-initializer and the database size at the start
|
| - ** of the transaction. Return an error code if anything goes wrong.
|
| - */
|
| - if( SQLITE_OK!=(rc = read32bits(pPager->jfd, iHdrOff+8, pNRec))
|
| - || SQLITE_OK!=(rc = read32bits(pPager->jfd, iHdrOff+12, &pPager->cksumInit))
|
| - || SQLITE_OK!=(rc = read32bits(pPager->jfd, iHdrOff+16, pDbSize))
|
| - ){
|
| - return rc;
|
| - }
|
| -
|
| - if( pPager->journalOff==0 ){
|
| - u32 iPageSize; /* Page-size field of journal header */
|
| - u32 iSectorSize; /* Sector-size field of journal header */
|
| - u16 iPageSize16; /* Copy of iPageSize in 16-bit variable */
|
| -
|
| - /* Read the page-size and sector-size journal header fields. */
|
| - if( SQLITE_OK!=(rc = read32bits(pPager->jfd, iHdrOff+20, &iSectorSize))
|
| - || SQLITE_OK!=(rc = read32bits(pPager->jfd, iHdrOff+24, &iPageSize))
|
| - ){
|
| - return rc;
|
| - }
|
| -
|
| - /* Check that the values read from the page-size and sector-size fields
|
| - ** are within range. To be 'in range', both values need to be a power
|
| - ** of two greater than or equal to 512, and not greater than their
|
| - ** respective compile time maximum limits.
|
| - */
|
| - if( iPageSize<512 || iSectorSize<512
|
| - || iPageSize>SQLITE_MAX_PAGE_SIZE || iSectorSize>MAX_SECTOR_SIZE
|
| - || ((iPageSize-1)&iPageSize)!=0 || ((iSectorSize-1)&iSectorSize)!=0
|
| - ){
|
| - /* If the either the page-size or sector-size in the journal-header is
|
| - ** invalid, then the process that wrote the journal-header must have
|
| - ** crashed before the header was synced. In this case stop reading
|
| - ** the journal file here.
|
| - */
|
| - return SQLITE_DONE;
|
| - }
|
| -
|
| - /* Update the page-size to match the value read from the journal.
|
| - ** Use a testcase() macro to make sure that malloc failure within
|
| - ** PagerSetPagesize() is tested.
|
| - */
|
| - iPageSize16 = (u16)iPageSize;
|
| - rc = sqlite3PagerSetPagesize(pPager, &iPageSize16, -1);
|
| - testcase( rc!=SQLITE_OK );
|
| - assert( rc!=SQLITE_OK || iPageSize16==(u16)iPageSize );
|
| -
|
| - /* Update the assumed sector-size to match the value used by
|
| - ** the process that created this journal. If this journal was
|
| - ** created by a process other than this one, then this routine
|
| - ** is being called from within pager_playback(). The local value
|
| - ** of Pager.sectorSize is restored at the end of that routine.
|
| - */
|
| - pPager->sectorSize = iSectorSize;
|
| - }
|
| -
|
| - pPager->journalOff += JOURNAL_HDR_SZ(pPager);
|
| - return rc;
|
| -}
|
| -
|
| -
|
| -/*
|
| -** Write the supplied master journal name into the journal file for pager
|
| -** pPager at the current location. The master journal name must be the last
|
| -** thing written to a journal file. If the pager is in full-sync mode, the
|
| -** journal file descriptor is advanced to the next sector boundary before
|
| -** anything is written. The format is:
|
| -**
|
| -** + 4 bytes: PAGER_MJ_PGNO.
|
| -** + N bytes: Master journal filename in utf-8.
|
| -** + 4 bytes: N (length of master journal name in bytes, no nul-terminator).
|
| -** + 4 bytes: Master journal name checksum.
|
| -** + 8 bytes: aJournalMagic[].
|
| -**
|
| -** The master journal page checksum is the sum of the bytes in the master
|
| -** journal name, where each byte is interpreted as a signed 8-bit integer.
|
| -**
|
| -** If zMaster is a NULL pointer (occurs for a single database transaction),
|
| -** this call is a no-op.
|
| -*/
|
| -static int writeMasterJournal(Pager *pPager, const char *zMaster){
|
| - int rc; /* Return code */
|
| - int nMaster; /* Length of string zMaster */
|
| - i64 iHdrOff; /* Offset of header in journal file */
|
| - i64 jrnlSize; /* Size of journal file on disk */
|
| - u32 cksum = 0; /* Checksum of string zMaster */
|
| -
|
| - if( !zMaster || pPager->setMaster
|
| - || pPager->journalMode==PAGER_JOURNALMODE_MEMORY
|
| - || pPager->journalMode==PAGER_JOURNALMODE_OFF
|
| - ){
|
| - return SQLITE_OK;
|
| - }
|
| - pPager->setMaster = 1;
|
| - assert( isOpen(pPager->jfd) );
|
| -
|
| - /* Calculate the length in bytes and the checksum of zMaster */
|
| - for(nMaster=0; zMaster[nMaster]; nMaster++){
|
| - cksum += zMaster[nMaster];
|
| - }
|
| -
|
| - /* If in full-sync mode, advance to the next disk sector before writing
|
| - ** the master journal name. This is in case the previous page written to
|
| - ** the journal has already been synced.
|
| - */
|
| - if( pPager->fullSync ){
|
| - pPager->journalOff = journalHdrOffset(pPager);
|
| - }
|
| - iHdrOff = pPager->journalOff;
|
| -
|
| - /* Write the master journal data to the end of the journal file. If
|
| - ** an error occurs, return the error code to the caller.
|
| - */
|
| - if( (0 != (rc = write32bits(pPager->jfd, iHdrOff, PAGER_MJ_PGNO(pPager))))
|
| - || (0 != (rc = sqlite3OsWrite(pPager->jfd, zMaster, nMaster, iHdrOff+4)))
|
| - || (0 != (rc = write32bits(pPager->jfd, iHdrOff+4+nMaster, nMaster)))
|
| - || (0 != (rc = write32bits(pPager->jfd, iHdrOff+4+nMaster+4, cksum)))
|
| - || (0 != (rc = sqlite3OsWrite(pPager->jfd, aJournalMagic, 8, iHdrOff+4+nMaster+8)))
|
| - ){
|
| - return rc;
|
| - }
|
| - pPager->journalOff += (nMaster+20);
|
| - pPager->needSync = !pPager->noSync;
|
| -
|
| - /* If the pager is in peristent-journal mode, then the physical
|
| - ** journal-file may extend past the end of the master-journal name
|
| - ** and 8 bytes of magic data just written to the file. This is
|
| - ** dangerous because the code to rollback a hot-journal file
|
| - ** will not be able to find the master-journal name to determine
|
| - ** whether or not the journal is hot.
|
| - **
|
| - ** Easiest thing to do in this scenario is to truncate the journal
|
| - ** file to the required size.
|
| - */
|
| - if( SQLITE_OK==(rc = sqlite3OsFileSize(pPager->jfd, &jrnlSize))
|
| - && jrnlSize>pPager->journalOff
|
| - ){
|
| - rc = sqlite3OsTruncate(pPager->jfd, pPager->journalOff);
|
| - }
|
| - return rc;
|
| -}
|
| -
|
| -/*
|
| -** Find a page in the hash table given its page number. Return
|
| -** a pointer to the page or NULL if the requested page is not
|
| -** already in memory.
|
| -*/
|
| -static PgHdr *pager_lookup(Pager *pPager, Pgno pgno){
|
| - PgHdr *p; /* Return value */
|
| -
|
| - /* It is not possible for a call to PcacheFetch() with createFlag==0 to
|
| - ** fail, since no attempt to allocate dynamic memory will be made.
|
| - */
|
| - (void)sqlite3PcacheFetch(pPager->pPCache, pgno, 0, &p);
|
| - return p;
|
| -}
|
| -
|
| -/*
|
| -** Unless the pager is in error-state, discard all in-memory pages. If
|
| -** the pager is in error-state, then this call is a no-op.
|
| -**
|
| -** TODO: Why can we not reset the pager while in error state?
|
| -*/
|
| -static void pager_reset(Pager *pPager){
|
| - if( SQLITE_OK==pPager->errCode ){
|
| - sqlite3BackupRestart(pPager->pBackup);
|
| - sqlite3PcacheClear(pPager->pPCache);
|
| - pPager->dbSizeValid = 0;
|
| - }
|
| -}
|
| -
|
| -/*
|
| -** Free all structures in the Pager.aSavepoint[] array and set both
|
| -** Pager.aSavepoint and Pager.nSavepoint to zero. Close the sub-journal
|
| -** if it is open and the pager is not in exclusive mode.
|
| -*/
|
| -static void releaseAllSavepoints(Pager *pPager){
|
| - int ii; /* Iterator for looping through Pager.aSavepoint */
|
| - for(ii=0; ii<pPager->nSavepoint; ii++){
|
| - sqlite3BitvecDestroy(pPager->aSavepoint[ii].pInSavepoint);
|
| - }
|
| - if( !pPager->exclusiveMode || sqlite3IsMemJournal(pPager->sjfd) ){
|
| - sqlite3OsClose(pPager->sjfd);
|
| - }
|
| - sqlite3_free(pPager->aSavepoint);
|
| - pPager->aSavepoint = 0;
|
| - pPager->nSavepoint = 0;
|
| - pPager->nSubRec = 0;
|
| -}
|
| -
|
| -/*
|
| -** Set the bit number pgno in the PagerSavepoint.pInSavepoint
|
| -** bitvecs of all open savepoints. Return SQLITE_OK if successful
|
| -** or SQLITE_NOMEM if a malloc failure occurs.
|
| -*/
|
| -static int addToSavepointBitvecs(Pager *pPager, Pgno pgno){
|
| - int ii; /* Loop counter */
|
| - int rc = SQLITE_OK; /* Result code */
|
| -
|
| - for(ii=0; ii<pPager->nSavepoint; ii++){
|
| - PagerSavepoint *p = &pPager->aSavepoint[ii];
|
| - if( pgno<=p->nOrig ){
|
| - rc |= sqlite3BitvecSet(p->pInSavepoint, pgno);
|
| - testcase( rc==SQLITE_NOMEM );
|
| - assert( rc==SQLITE_OK || rc==SQLITE_NOMEM );
|
| - }
|
| - }
|
| - return rc;
|
| -}
|
| -
|
| -/*
|
| -** Unlock the database file. This function is a no-op if the pager
|
| -** is in exclusive mode.
|
| -**
|
| -** If the pager is currently in error state, discard the contents of
|
| -** the cache and reset the Pager structure internal state. If there is
|
| -** an open journal-file, then the next time a shared-lock is obtained
|
| -** on the pager file (by this or any other process), it will be
|
| -** treated as a hot-journal and rolled back.
|
| -*/
|
| -static void pager_unlock(Pager *pPager){
|
| - if( !pPager->exclusiveMode ){
|
| - int rc; /* Return code */
|
| -
|
| - /* Always close the journal file when dropping the database lock.
|
| - ** Otherwise, another connection with journal_mode=delete might
|
| - ** delete the file out from under us.
|
| - */
|
| - sqlite3OsClose(pPager->jfd);
|
| - sqlite3BitvecDestroy(pPager->pInJournal);
|
| - pPager->pInJournal = 0;
|
| - releaseAllSavepoints(pPager);
|
| -
|
| - /* If the file is unlocked, somebody else might change it. The
|
| - ** values stored in Pager.dbSize etc. might become invalid if
|
| - ** this happens. TODO: Really, this doesn't need to be cleared
|
| - ** until the change-counter check fails in PagerSharedLock().
|
| - */
|
| - pPager->dbSizeValid = 0;
|
| -
|
| - rc = osUnlock(pPager->fd, NO_LOCK);
|
| - if( rc ){
|
| - pPager->errCode = rc;
|
| - }
|
| - IOTRACE(("UNLOCK %p\n", pPager))
|
| -
|
| - /* If Pager.errCode is set, the contents of the pager cache cannot be
|
| - ** trusted. Now that the pager file is unlocked, the contents of the
|
| - ** cache can be discarded and the error code safely cleared.
|
| - */
|
| - if( pPager->errCode ){
|
| - if( rc==SQLITE_OK ){
|
| - pPager->errCode = SQLITE_OK;
|
| - }
|
| - pager_reset(pPager);
|
| - }
|
| -
|
| - pPager->changeCountDone = 0;
|
| - pPager->state = PAGER_UNLOCK;
|
| - }
|
| -}
|
| -
|
| -/*
|
| -** This function should be called when an IOERR, CORRUPT or FULL error
|
| -** may have occurred. The first argument is a pointer to the pager
|
| -** structure, the second the error-code about to be returned by a pager
|
| -** API function. The value returned is a copy of the second argument
|
| -** to this function.
|
| -**
|
| -** If the second argument is SQLITE_IOERR, SQLITE_CORRUPT, or SQLITE_FULL
|
| -** the error becomes persistent. Until the persisten error is cleared,
|
| -** subsequent API calls on this Pager will immediately return the same
|
| -** error code.
|
| -**
|
| -** A persistent error indicates that the contents of the pager-cache
|
| -** cannot be trusted. This state can be cleared by completely discarding
|
| -** the contents of the pager-cache. If a transaction was active when
|
| -** the persistent error occurred, then the rollback journal may need
|
| -** to be replayed to restore the contents of the database file (as if
|
| -** it were a hot-journal).
|
| -*/
|
| -static int pager_error(Pager *pPager, int rc){
|
| - int rc2 = rc & 0xff;
|
| - assert( rc==SQLITE_OK || !MEMDB );
|
| - assert(
|
| - pPager->errCode==SQLITE_FULL ||
|
| - pPager->errCode==SQLITE_OK ||
|
| - (pPager->errCode & 0xff)==SQLITE_IOERR
|
| - );
|
| - if( rc2==SQLITE_FULL || rc2==SQLITE_IOERR ){
|
| - pPager->errCode = rc;
|
| - }
|
| - return rc;
|
| -}
|
| -
|
| -/*
|
| -** Execute a rollback if a transaction is active and unlock the
|
| -** database file.
|
| -**
|
| -** If the pager has already entered the error state, do not attempt
|
| -** the rollback at this time. Instead, pager_unlock() is called. The
|
| -** call to pager_unlock() will discard all in-memory pages, unlock
|
| -** the database file and clear the error state. If this means that
|
| -** there is a hot-journal left in the file-system, the next connection
|
| -** to obtain a shared lock on the pager (which may be this one) will
|
| -** roll it back.
|
| -**
|
| -** If the pager has not already entered the error state, but an IO or
|
| -** malloc error occurs during a rollback, then this will itself cause
|
| -** the pager to enter the error state. Which will be cleared by the
|
| -** call to pager_unlock(), as described above.
|
| -*/
|
| -static void pagerUnlockAndRollback(Pager *pPager){
|
| - if( pPager->errCode==SQLITE_OK && pPager->state>=PAGER_RESERVED ){
|
| - sqlite3BeginBenignMalloc();
|
| - sqlite3PagerRollback(pPager);
|
| - sqlite3EndBenignMalloc();
|
| - }
|
| - pager_unlock(pPager);
|
| -}
|
| -
|
| -/*
|
| -** This routine ends a transaction. A transaction is usually ended by
|
| -** either a COMMIT or a ROLLBACK operation. This routine may be called
|
| -** after rollback of a hot-journal, or if an error occurs while opening
|
| -** the journal file or writing the very first journal-header of a
|
| -** database transaction.
|
| -**
|
| -** If the pager is in PAGER_SHARED or PAGER_UNLOCK state when this
|
| -** routine is called, it is a no-op (returns SQLITE_OK).
|
| -**
|
| -** Otherwise, any active savepoints are released.
|
| -**
|
| -** If the journal file is open, then it is "finalized". Once a journal
|
| -** file has been finalized it is not possible to use it to roll back a
|
| -** transaction. Nor will it be considered to be a hot-journal by this
|
| -** or any other database connection. Exactly how a journal is finalized
|
| -** depends on whether or not the pager is running in exclusive mode and
|
| -** the current journal-mode (Pager.journalMode value), as follows:
|
| -**
|
| -** journalMode==MEMORY
|
| -** Journal file descriptor is simply closed. This destroys an
|
| -** in-memory journal.
|
| -**
|
| -** journalMode==TRUNCATE
|
| -** Journal file is truncated to zero bytes in size.
|
| -**
|
| -** journalMode==PERSIST
|
| -** The first 28 bytes of the journal file are zeroed. This invalidates
|
| -** the first journal header in the file, and hence the entire journal
|
| -** file. An invalid journal file cannot be rolled back.
|
| -**
|
| -** journalMode==DELETE
|
| -** The journal file is closed and deleted using sqlite3OsDelete().
|
| -**
|
| -** If the pager is running in exclusive mode, this method of finalizing
|
| -** the journal file is never used. Instead, if the journalMode is
|
| -** DELETE and the pager is in exclusive mode, the method described under
|
| -** journalMode==PERSIST is used instead.
|
| -**
|
| -** After the journal is finalized, if running in non-exclusive mode, the
|
| -** pager moves to PAGER_SHARED state (and downgrades the lock on the
|
| -** database file accordingly).
|
| -**
|
| -** If the pager is running in exclusive mode and is in PAGER_SYNCED state,
|
| -** it moves to PAGER_EXCLUSIVE. No locks are downgraded when running in
|
| -** exclusive mode.
|
| -**
|
| -** SQLITE_OK is returned if no error occurs. If an error occurs during
|
| -** any of the IO operations to finalize the journal file or unlock the
|
| -** database then the IO error code is returned to the user. If the
|
| -** operation to finalize the journal file fails, then the code still
|
| -** tries to unlock the database file if not in exclusive mode. If the
|
| -** unlock operation fails as well, then the first error code related
|
| -** to the first error encountered (the journal finalization one) is
|
| -** returned.
|
| -*/
|
| -static int pager_end_transaction(Pager *pPager, int hasMaster){
|
| - int rc = SQLITE_OK; /* Error code from journal finalization operation */
|
| - int rc2 = SQLITE_OK; /* Error code from db file unlock operation */
|
| -
|
| - if( pPager->state<PAGER_RESERVED ){
|
| - return SQLITE_OK;
|
| - }
|
| - releaseAllSavepoints(pPager);
|
| -
|
| - assert( isOpen(pPager->jfd) || pPager->pInJournal==0 );
|
| - if( isOpen(pPager->jfd) ){
|
| -
|
| - /* Finalize the journal file. */
|
| - if( sqlite3IsMemJournal(pPager->jfd) ){
|
| - assert( pPager->journalMode==PAGER_JOURNALMODE_MEMORY );
|
| - sqlite3OsClose(pPager->jfd);
|
| - }else if( pPager->journalMode==PAGER_JOURNALMODE_TRUNCATE ){
|
| - if( pPager->journalOff==0 ){
|
| - rc = SQLITE_OK;
|
| - }else{
|
| - rc = sqlite3OsTruncate(pPager->jfd, 0);
|
| - }
|
| - pPager->journalOff = 0;
|
| - pPager->journalStarted = 0;
|
| - }else if( pPager->exclusiveMode
|
| - || pPager->journalMode==PAGER_JOURNALMODE_PERSIST
|
| - ){
|
| - rc = zeroJournalHdr(pPager, hasMaster);
|
| - pager_error(pPager, rc);
|
| - pPager->journalOff = 0;
|
| - pPager->journalStarted = 0;
|
| - }else{
|
| - /* This branch may be executed with Pager.journalMode==MEMORY if
|
| - ** a hot-journal was just rolled back. In this case the journal
|
| - ** file should be closed and deleted. If this connection writes to
|
| - ** the database file, it will do so using an in-memory journal. */
|
| - assert( pPager->journalMode==PAGER_JOURNALMODE_DELETE
|
| - || pPager->journalMode==PAGER_JOURNALMODE_MEMORY
|
| - );
|
| - sqlite3OsClose(pPager->jfd);
|
| - if( !pPager->tempFile ){
|
| - rc = sqlite3OsDelete(pPager->pVfs, pPager->zJournal, 0);
|
| - }
|
| - }
|
| -
|
| -#ifdef SQLITE_CHECK_PAGES
|
| - sqlite3PcacheIterateDirty(pPager->pPCache, pager_set_pagehash);
|
| -#endif
|
| -
|
| - sqlite3PcacheCleanAll(pPager->pPCache);
|
| - sqlite3BitvecDestroy(pPager->pInJournal);
|
| - pPager->pInJournal = 0;
|
| - pPager->nRec = 0;
|
| - }
|
| -
|
| - if( !pPager->exclusiveMode ){
|
| - rc2 = osUnlock(pPager->fd, SHARED_LOCK);
|
| - pPager->state = PAGER_SHARED;
|
| - pPager->changeCountDone = 0;
|
| - }else if( pPager->state==PAGER_SYNCED ){
|
| - pPager->state = PAGER_EXCLUSIVE;
|
| - }
|
| - pPager->setMaster = 0;
|
| - pPager->needSync = 0;
|
| - pPager->dbModified = 0;
|
| -
|
| - /* TODO: Is this optimal? Why is the db size invalidated here
|
| - ** when the database file is not unlocked? */
|
| - pPager->dbOrigSize = 0;
|
| - sqlite3PcacheTruncate(pPager->pPCache, pPager->dbSize);
|
| - if( !MEMDB ){
|
| - pPager->dbSizeValid = 0;
|
| - }
|
| -
|
| - return (rc==SQLITE_OK?rc2:rc);
|
| -}
|
| -
|
| -/*
|
| -** Parameter aData must point to a buffer of pPager->pageSize bytes
|
| -** of data. Compute and return a checksum based ont the contents of the
|
| -** page of data and the current value of pPager->cksumInit.
|
| -**
|
| -** This is not a real checksum. It is really just the sum of the
|
| -** random initial value (pPager->cksumInit) and every 200th byte
|
| -** of the page data, starting with byte offset (pPager->pageSize%200).
|
| -** Each byte is interpreted as an 8-bit unsigned integer.
|
| -**
|
| -** Changing the formula used to compute this checksum results in an
|
| -** incompatible journal file format.
|
| -**
|
| -** If journal corruption occurs due to a power failure, the most likely
|
| -** scenario is that one end or the other of the record will be changed.
|
| -** It is much less likely that the two ends of the journal record will be
|
| -** correct and the middle be corrupt. Thus, this "checksum" scheme,
|
| -** though fast and simple, catches the mostly likely kind of corruption.
|
| -*/
|
| -static u32 pager_cksum(Pager *pPager, const u8 *aData){
|
| - u32 cksum = pPager->cksumInit; /* Checksum value to return */
|
| - int i = pPager->pageSize-200; /* Loop counter */
|
| - while( i>0 ){
|
| - cksum += aData[i];
|
| - i -= 200;
|
| - }
|
| - return cksum;
|
| -}
|
| -
|
| -/*
|
| -** Read a single page from either the journal file (if isMainJrnl==1) or
|
| -** from the sub-journal (if isMainJrnl==0) and playback that page.
|
| -** The page begins at offset *pOffset into the file. The *pOffset
|
| -** value is increased to the start of the next page in the journal.
|
| -**
|
| -** The isMainJrnl flag is true if this is the main rollback journal and
|
| -** false for the statement journal. The main rollback journal uses
|
| -** checksums - the statement journal does not.
|
| -**
|
| -** If the page number of the page record read from the (sub-)journal file
|
| -** is greater than the current value of Pager.dbSize, then playback is
|
| -** skipped and SQLITE_OK is returned.
|
| -**
|
| -** If pDone is not NULL, then it is a record of pages that have already
|
| -** been played back. If the page at *pOffset has already been played back
|
| -** (if the corresponding pDone bit is set) then skip the playback.
|
| -** Make sure the pDone bit corresponding to the *pOffset page is set
|
| -** prior to returning.
|
| -**
|
| -** If the page record is successfully read from the (sub-)journal file
|
| -** and played back, then SQLITE_OK is returned. If an IO error occurs
|
| -** while reading the record from the (sub-)journal file or while writing
|
| -** to the database file, then the IO error code is returned. If data
|
| -** is successfully read from the (sub-)journal file but appears to be
|
| -** corrupted, SQLITE_DONE is returned. Data is considered corrupted in
|
| -** two circumstances:
|
| -**
|
| -** * If the record page-number is illegal (0 or PAGER_MJ_PGNO), or
|
| -** * If the record is being rolled back from the main journal file
|
| -** and the checksum field does not match the record content.
|
| -**
|
| -** Neither of these two scenarios are possible during a savepoint rollback.
|
| -**
|
| -** If this is a savepoint rollback, then memory may have to be dynamically
|
| -** allocated by this function. If this is the case and an allocation fails,
|
| -** SQLITE_NOMEM is returned.
|
| -*/
|
| -static int pager_playback_one_page(
|
| - Pager *pPager, /* The pager being played back */
|
| - int isMainJrnl, /* 1 -> main journal. 0 -> sub-journal. */
|
| - int isUnsync, /* True if reading from unsynced main journal */
|
| - i64 *pOffset, /* Offset of record to playback */
|
| - int isSavepnt, /* True for a savepoint rollback */
|
| - Bitvec *pDone /* Bitvec of pages already played back */
|
| -){
|
| - int rc;
|
| - PgHdr *pPg; /* An existing page in the cache */
|
| - Pgno pgno; /* The page number of a page in journal */
|
| - u32 cksum; /* Checksum used for sanity checking */
|
| - u8 *aData; /* Temporary storage for the page */
|
| - sqlite3_file *jfd; /* The file descriptor for the journal file */
|
| -
|
| - assert( (isMainJrnl&~1)==0 ); /* isMainJrnl is 0 or 1 */
|
| - assert( (isSavepnt&~1)==0 ); /* isSavepnt is 0 or 1 */
|
| - assert( isMainJrnl || pDone ); /* pDone always used on sub-journals */
|
| - assert( isSavepnt || pDone==0 ); /* pDone never used on non-savepoint */
|
| -
|
| - aData = (u8*)pPager->pTmpSpace;
|
| - assert( aData ); /* Temp storage must have already been allocated */
|
| -
|
| - /* Read the page number and page data from the journal or sub-journal
|
| - ** file. Return an error code to the caller if an IO error occurs.
|
| - */
|
| - jfd = isMainJrnl ? pPager->jfd : pPager->sjfd;
|
| - rc = read32bits(jfd, *pOffset, &pgno);
|
| - if( rc!=SQLITE_OK ) return rc;
|
| - rc = sqlite3OsRead(jfd, aData, pPager->pageSize, (*pOffset)+4);
|
| - if( rc!=SQLITE_OK ) return rc;
|
| - *pOffset += pPager->pageSize + 4 + isMainJrnl*4;
|
| -
|
| - /* Sanity checking on the page. This is more important that I originally
|
| - ** thought. If a power failure occurs while the journal is being written,
|
| - ** it could cause invalid data to be written into the journal. We need to
|
| - ** detect this invalid data (with high probability) and ignore it.
|
| - */
|
| - if( pgno==0 || pgno==PAGER_MJ_PGNO(pPager) ){
|
| - assert( !isSavepnt );
|
| - return SQLITE_DONE;
|
| - }
|
| - if( pgno>(Pgno)pPager->dbSize || sqlite3BitvecTest(pDone, pgno) ){
|
| - return SQLITE_OK;
|
| - }
|
| - if( isMainJrnl ){
|
| - rc = read32bits(jfd, (*pOffset)-4, &cksum);
|
| - if( rc ) return rc;
|
| - if( !isSavepnt && pager_cksum(pPager, aData)!=cksum ){
|
| - return SQLITE_DONE;
|
| - }
|
| - }
|
| -
|
| - if( pDone && (rc = sqlite3BitvecSet(pDone, pgno))!=SQLITE_OK ){
|
| - return rc;
|
| - }
|
| -
|
| - assert( pPager->state==PAGER_RESERVED || pPager->state>=PAGER_EXCLUSIVE );
|
| -
|
| - /* If the pager is in RESERVED state, then there must be a copy of this
|
| - ** page in the pager cache. In this case just update the pager cache,
|
| - ** not the database file. The page is left marked dirty in this case.
|
| - **
|
| - ** An exception to the above rule: If the database is in no-sync mode
|
| - ** and a page is moved during an incremental vacuum then the page may
|
| - ** not be in the pager cache. Later: if a malloc() or IO error occurs
|
| - ** during a Movepage() call, then the page may not be in the cache
|
| - ** either. So the condition described in the above paragraph is not
|
| - ** assert()able.
|
| - **
|
| - ** If in EXCLUSIVE state, then we update the pager cache if it exists
|
| - ** and the main file. The page is then marked not dirty.
|
| - **
|
| - ** Ticket #1171: The statement journal might contain page content that is
|
| - ** different from the page content at the start of the transaction.
|
| - ** This occurs when a page is changed prior to the start of a statement
|
| - ** then changed again within the statement. When rolling back such a
|
| - ** statement we must not write to the original database unless we know
|
| - ** for certain that original page contents are synced into the main rollback
|
| - ** journal. Otherwise, a power loss might leave modified data in the
|
| - ** database file without an entry in the rollback journal that can
|
| - ** restore the database to its original form. Two conditions must be
|
| - ** met before writing to the database files. (1) the database must be
|
| - ** locked. (2) we know that the original page content is fully synced
|
| - ** in the main journal either because the page is not in cache or else
|
| - ** the page is marked as needSync==0.
|
| - **
|
| - ** 2008-04-14: When attempting to vacuum a corrupt database file, it
|
| - ** is possible to fail a statement on a database that does not yet exist.
|
| - ** Do not attempt to write if database file has never been opened.
|
| - */
|
| - pPg = pager_lookup(pPager, pgno);
|
| - assert( pPg || !MEMDB );
|
| - PAGERTRACE(("PLAYBACK %d page %d hash(%08x) %s\n",
|
| - PAGERID(pPager), pgno, pager_datahash(pPager->pageSize, aData),
|
| - (isMainJrnl?"main-journal":"sub-journal")
|
| - ));
|
| - if( (pPager->state>=PAGER_EXCLUSIVE)
|
| - && (pPg==0 || 0==(pPg->flags&PGHDR_NEED_SYNC))
|
| - && isOpen(pPager->fd)
|
| - && !isUnsync
|
| - ){
|
| - i64 ofst = (pgno-1)*(i64)pPager->pageSize;
|
| - rc = sqlite3OsWrite(pPager->fd, aData, pPager->pageSize, ofst);
|
| - if( pgno>pPager->dbFileSize ){
|
| - pPager->dbFileSize = pgno;
|
| - }
|
| - if( pPager->pBackup ){
|
| - CODEC1(pPager, aData, pgno, 3, rc=SQLITE_NOMEM);
|
| - sqlite3BackupUpdate(pPager->pBackup, pgno, aData);
|
| - CODEC1(pPager, aData, pgno, 0, rc=SQLITE_NOMEM);
|
| - }
|
| - }else if( !isMainJrnl && pPg==0 ){
|
| - /* If this is a rollback of a savepoint and data was not written to
|
| - ** the database and the page is not in-memory, there is a potential
|
| - ** problem. When the page is next fetched by the b-tree layer, it
|
| - ** will be read from the database file, which may or may not be
|
| - ** current.
|
| - **
|
| - ** There are a couple of different ways this can happen. All are quite
|
| - ** obscure. When running in synchronous mode, this can only happen
|
| - ** if the page is on the free-list at the start of the transaction, then
|
| - ** populated, then moved using sqlite3PagerMovepage().
|
| - **
|
| - ** The solution is to add an in-memory page to the cache containing
|
| - ** the data just read from the sub-journal. Mark the page as dirty
|
| - ** and if the pager requires a journal-sync, then mark the page as
|
| - ** requiring a journal-sync before it is written.
|
| - */
|
| - assert( isSavepnt );
|
| - if( (rc = sqlite3PagerAcquire(pPager, pgno, &pPg, 1))!=SQLITE_OK ){
|
| - return rc;
|
| - }
|
| - pPg->flags &= ~PGHDR_NEED_READ;
|
| - sqlite3PcacheMakeDirty(pPg);
|
| - }
|
| - if( pPg ){
|
| - /* No page should ever be explicitly rolled back that is in use, except
|
| - ** for page 1 which is held in use in order to keep the lock on the
|
| - ** database active. However such a page may be rolled back as a result
|
| - ** of an internal error resulting in an automatic call to
|
| - ** sqlite3PagerRollback().
|
| - */
|
| - void *pData;
|
| - pData = pPg->pData;
|
| - memcpy(pData, aData, pPager->pageSize);
|
| - pPager->xReiniter(pPg);
|
| - if( isMainJrnl && (!isSavepnt || *pOffset<=pPager->journalHdr) ){
|
| - /* If the contents of this page were just restored from the main
|
| - ** journal file, then its content must be as they were when the
|
| - ** transaction was first opened. In this case we can mark the page
|
| - ** as clean, since there will be no need to write it out to the.
|
| - **
|
| - ** There is one exception to this rule. If the page is being rolled
|
| - ** back as part of a savepoint (or statement) rollback from an
|
| - ** unsynced portion of the main journal file, then it is not safe
|
| - ** to mark the page as clean. This is because marking the page as
|
| - ** clean will clear the PGHDR_NEED_SYNC flag. Since the page is
|
| - ** already in the journal file (recorded in Pager.pInJournal) and
|
| - ** the PGHDR_NEED_SYNC flag is cleared, if the page is written to
|
| - ** again within this transaction, it will be marked as dirty but
|
| - ** the PGHDR_NEED_SYNC flag will not be set. It could then potentially
|
| - ** be written out into the database file before its journal file
|
| - ** segment is synced. If a crash occurs during or following this,
|
| - ** database corruption may ensue.
|
| - */
|
| - sqlite3PcacheMakeClean(pPg);
|
| - }
|
| -#ifdef SQLITE_CHECK_PAGES
|
| - pPg->pageHash = pager_pagehash(pPg);
|
| -#endif
|
| - /* If this was page 1, then restore the value of Pager.dbFileVers.
|
| - ** Do this before any decoding. */
|
| - if( pgno==1 ){
|
| - memcpy(&pPager->dbFileVers, &((u8*)pData)[24],sizeof(pPager->dbFileVers));
|
| - }
|
| -
|
| - /* Decode the page just read from disk */
|
| - CODEC1(pPager, pData, pPg->pgno, 3, rc=SQLITE_NOMEM);
|
| - sqlite3PcacheRelease(pPg);
|
| - }
|
| - return rc;
|
| -}
|
| -
|
| -/*
|
| -** Parameter zMaster is the name of a master journal file. A single journal
|
| -** file that referred to the master journal file has just been rolled back.
|
| -** This routine checks if it is possible to delete the master journal file,
|
| -** and does so if it is.
|
| -**
|
| -** Argument zMaster may point to Pager.pTmpSpace. So that buffer is not
|
| -** available for use within this function.
|
| -**
|
| -** When a master journal file is created, it is populated with the names
|
| -** of all of its child journals, one after another, formatted as utf-8
|
| -** encoded text. The end of each child journal file is marked with a
|
| -** nul-terminator byte (0x00). i.e. the entire contents of a master journal
|
| -** file for a transaction involving two databases might be:
|
| -**
|
| -** "/home/bill/a.db-journal\x00/home/bill/b.db-journal\x00"
|
| -**
|
| -** A master journal file may only be deleted once all of its child
|
| -** journals have been rolled back.
|
| -**
|
| -** This function reads the contents of the master-journal file into
|
| -** memory and loops through each of the child journal names. For
|
| -** each child journal, it checks if:
|
| -**
|
| -** * if the child journal exists, and if so
|
| -** * if the child journal contains a reference to master journal
|
| -** file zMaster
|
| -**
|
| -** If a child journal can be found that matches both of the criteria
|
| -** above, this function returns without doing anything. Otherwise, if
|
| -** no such child journal can be found, file zMaster is deleted from
|
| -** the file-system using sqlite3OsDelete().
|
| -**
|
| -** If an IO error within this function, an error code is returned. This
|
| -** function allocates memory by calling sqlite3Malloc(). If an allocation
|
| -** fails, SQLITE_NOMEM is returned. Otherwise, if no IO or malloc errors
|
| -** occur, SQLITE_OK is returned.
|
| -**
|
| -** TODO: This function allocates a single block of memory to load
|
| -** the entire contents of the master journal file. This could be
|
| -** a couple of kilobytes or so - potentially larger than the page
|
| -** size.
|
| -*/
|
| -static int pager_delmaster(Pager *pPager, const char *zMaster){
|
| - sqlite3_vfs *pVfs = pPager->pVfs;
|
| - int rc; /* Return code */
|
| - sqlite3_file *pMaster; /* Malloc'd master-journal file descriptor */
|
| - sqlite3_file *pJournal; /* Malloc'd child-journal file descriptor */
|
| - char *zMasterJournal = 0; /* Contents of master journal file */
|
| - i64 nMasterJournal; /* Size of master journal file */
|
| -
|
| - /* Allocate space for both the pJournal and pMaster file descriptors.
|
| - ** If successful, open the master journal file for reading.
|
| - */
|
| - pMaster = (sqlite3_file *)sqlite3MallocZero(pVfs->szOsFile * 2);
|
| - pJournal = (sqlite3_file *)(((u8 *)pMaster) + pVfs->szOsFile);
|
| - if( !pMaster ){
|
| - rc = SQLITE_NOMEM;
|
| - }else{
|
| - const int flags = (SQLITE_OPEN_READONLY|SQLITE_OPEN_MASTER_JOURNAL);
|
| - rc = sqlite3OsOpen(pVfs, zMaster, pMaster, flags, 0);
|
| - }
|
| - if( rc!=SQLITE_OK ) goto delmaster_out;
|
| -
|
| - rc = sqlite3OsFileSize(pMaster, &nMasterJournal);
|
| - if( rc!=SQLITE_OK ) goto delmaster_out;
|
| -
|
| - if( nMasterJournal>0 ){
|
| - char *zJournal;
|
| - char *zMasterPtr = 0;
|
| - int nMasterPtr = pVfs->mxPathname+1;
|
| -
|
| - /* Load the entire master journal file into space obtained from
|
| - ** sqlite3_malloc() and pointed to by zMasterJournal.
|
| - */
|
| - zMasterJournal = sqlite3Malloc((int)nMasterJournal + nMasterPtr + 1);
|
| - if( !zMasterJournal ){
|
| - rc = SQLITE_NOMEM;
|
| - goto delmaster_out;
|
| - }
|
| - zMasterPtr = &zMasterJournal[nMasterJournal+1];
|
| - rc = sqlite3OsRead(pMaster, zMasterJournal, (int)nMasterJournal, 0);
|
| - if( rc!=SQLITE_OK ) goto delmaster_out;
|
| - zMasterJournal[nMasterJournal] = 0;
|
| -
|
| - zJournal = zMasterJournal;
|
| - while( (zJournal-zMasterJournal)<nMasterJournal ){
|
| - int exists;
|
| - rc = sqlite3OsAccess(pVfs, zJournal, SQLITE_ACCESS_EXISTS, &exists);
|
| - if( rc!=SQLITE_OK ){
|
| - goto delmaster_out;
|
| - }
|
| - if( exists ){
|
| - /* One of the journals pointed to by the master journal exists.
|
| - ** Open it and check if it points at the master journal. If
|
| - ** so, return without deleting the master journal file.
|
| - */
|
| - int c;
|
| - int flags = (SQLITE_OPEN_READONLY|SQLITE_OPEN_MAIN_JOURNAL);
|
| - rc = sqlite3OsOpen(pVfs, zJournal, pJournal, flags, 0);
|
| - if( rc!=SQLITE_OK ){
|
| - goto delmaster_out;
|
| - }
|
| -
|
| - rc = readMasterJournal(pJournal, zMasterPtr, nMasterPtr);
|
| - sqlite3OsClose(pJournal);
|
| - if( rc!=SQLITE_OK ){
|
| - goto delmaster_out;
|
| - }
|
| -
|
| - c = zMasterPtr[0]!=0 && strcmp(zMasterPtr, zMaster)==0;
|
| - if( c ){
|
| - /* We have a match. Do not delete the master journal file. */
|
| - goto delmaster_out;
|
| - }
|
| - }
|
| - zJournal += (sqlite3Strlen30(zJournal)+1);
|
| - }
|
| - }
|
| -
|
| - rc = sqlite3OsDelete(pVfs, zMaster, 0);
|
| -
|
| -delmaster_out:
|
| - if( zMasterJournal ){
|
| - sqlite3_free(zMasterJournal);
|
| - }
|
| - if( pMaster ){
|
| - sqlite3OsClose(pMaster);
|
| - assert( !isOpen(pJournal) );
|
| - }
|
| - sqlite3_free(pMaster);
|
| - return rc;
|
| -}
|
| -
|
| -
|
| -/*
|
| -** This function is used to change the actual size of the database
|
| -** file in the file-system. This only happens when committing a transaction,
|
| -** or rolling back a transaction (including rolling back a hot-journal).
|
| -**
|
| -** If the main database file is not open, or an exclusive lock is not
|
| -** held, this function is a no-op. Otherwise, the size of the file is
|
| -** changed to nPage pages (nPage*pPager->pageSize bytes). If the file
|
| -** on disk is currently larger than nPage pages, then use the VFS
|
| -** xTruncate() method to truncate it.
|
| -**
|
| -** Or, it might might be the case that the file on disk is smaller than
|
| -** nPage pages. Some operating system implementations can get confused if
|
| -** you try to truncate a file to some size that is larger than it
|
| -** currently is, so detect this case and write a single zero byte to
|
| -** the end of the new file instead.
|
| -**
|
| -** If successful, return SQLITE_OK. If an IO error occurs while modifying
|
| -** the database file, return the error code to the caller.
|
| -*/
|
| -static int pager_truncate(Pager *pPager, Pgno nPage){
|
| - int rc = SQLITE_OK;
|
| - if( pPager->state>=PAGER_EXCLUSIVE && isOpen(pPager->fd) ){
|
| - i64 currentSize, newSize;
|
| - /* TODO: Is it safe to use Pager.dbFileSize here? */
|
| - rc = sqlite3OsFileSize(pPager->fd, ¤tSize);
|
| - newSize = pPager->pageSize*(i64)nPage;
|
| - if( rc==SQLITE_OK && currentSize!=newSize ){
|
| - if( currentSize>newSize ){
|
| - rc = sqlite3OsTruncate(pPager->fd, newSize);
|
| - }else{
|
| - rc = sqlite3OsWrite(pPager->fd, "", 1, newSize-1);
|
| - }
|
| - if( rc==SQLITE_OK ){
|
| - pPager->dbFileSize = nPage;
|
| - }
|
| - }
|
| - }
|
| - return rc;
|
| -}
|
| -
|
| -/*
|
| -** Set the value of the Pager.sectorSize variable for the given
|
| -** pager based on the value returned by the xSectorSize method
|
| -** of the open database file. The sector size will be used used
|
| -** to determine the size and alignment of journal header and
|
| -** master journal pointers within created journal files.
|
| -**
|
| -** For temporary files the effective sector size is always 512 bytes.
|
| -**
|
| -** Otherwise, for non-temporary files, the effective sector size is
|
| -** the value returned by the xSectorSize() method rounded up to 512 if
|
| -** it is less than 512, or rounded down to MAX_SECTOR_SIZE if it
|
| -** is greater than MAX_SECTOR_SIZE.
|
| -*/
|
| -static void setSectorSize(Pager *pPager){
|
| - assert( isOpen(pPager->fd) || pPager->tempFile );
|
| -
|
| - if( !pPager->tempFile ){
|
| - /* Sector size doesn't matter for temporary files. Also, the file
|
| - ** may not have been opened yet, in which case the OsSectorSize()
|
| - ** call will segfault.
|
| - */
|
| - pPager->sectorSize = sqlite3OsSectorSize(pPager->fd);
|
| - }
|
| - if( pPager->sectorSize<512 ){
|
| - pPager->sectorSize = 512;
|
| - }
|
| - if( pPager->sectorSize>MAX_SECTOR_SIZE ){
|
| - assert( MAX_SECTOR_SIZE>=512 );
|
| - pPager->sectorSize = MAX_SECTOR_SIZE;
|
| - }
|
| -}
|
| -
|
| -/*
|
| -** Playback the journal and thus restore the database file to
|
| -** the state it was in before we started making changes.
|
| -**
|
| -** The journal file format is as follows:
|
| -**
|
| -** (1) 8 byte prefix. A copy of aJournalMagic[].
|
| -** (2) 4 byte big-endian integer which is the number of valid page records
|
| -** in the journal. If this value is 0xffffffff, then compute the
|
| -** number of page records from the journal size.
|
| -** (3) 4 byte big-endian integer which is the initial value for the
|
| -** sanity checksum.
|
| -** (4) 4 byte integer which is the number of pages to truncate the
|
| -** database to during a rollback.
|
| -** (5) 4 byte big-endian integer which is the sector size. The header
|
| -** is this many bytes in size.
|
| -** (6) 4 byte big-endian integer which is the page case.
|
| -** (7) 4 byte integer which is the number of bytes in the master journal
|
| -** name. The value may be zero (indicate that there is no master
|
| -** journal.)
|
| -** (8) N bytes of the master journal name. The name will be nul-terminated
|
| -** and might be shorter than the value read from (5). If the first byte
|
| -** of the name is \000 then there is no master journal. The master
|
| -** journal name is stored in UTF-8.
|
| -** (9) Zero or more pages instances, each as follows:
|
| -** + 4 byte page number.
|
| -** + pPager->pageSize bytes of data.
|
| -** + 4 byte checksum
|
| -**
|
| -** When we speak of the journal header, we mean the first 8 items above.
|
| -** Each entry in the journal is an instance of the 9th item.
|
| -**
|
| -** Call the value from the second bullet "nRec". nRec is the number of
|
| -** valid page entries in the journal. In most cases, you can compute the
|
| -** value of nRec from the size of the journal file. But if a power
|
| -** failure occurred while the journal was being written, it could be the
|
| -** case that the size of the journal file had already been increased but
|
| -** the extra entries had not yet made it safely to disk. In such a case,
|
| -** the value of nRec computed from the file size would be too large. For
|
| -** that reason, we always use the nRec value in the header.
|
| -**
|
| -** If the nRec value is 0xffffffff it means that nRec should be computed
|
| -** from the file size. This value is used when the user selects the
|
| -** no-sync option for the journal. A power failure could lead to corruption
|
| -** in this case. But for things like temporary table (which will be
|
| -** deleted when the power is restored) we don't care.
|
| -**
|
| -** If the file opened as the journal file is not a well-formed
|
| -** journal file then all pages up to the first corrupted page are rolled
|
| -** back (or no pages if the journal header is corrupted). The journal file
|
| -** is then deleted and SQLITE_OK returned, just as if no corruption had
|
| -** been encountered.
|
| -**
|
| -** If an I/O or malloc() error occurs, the journal-file is not deleted
|
| -** and an error code is returned.
|
| -**
|
| -** The isHot parameter indicates that we are trying to rollback a journal
|
| -** that might be a hot journal. Or, it could be that the journal is
|
| -** preserved because of JOURNALMODE_PERSIST or JOURNALMODE_TRUNCATE.
|
| -** If the journal really is hot, reset the pager cache prior rolling
|
| -** back any content. If the journal is merely persistent, no reset is
|
| -** needed.
|
| -*/
|
| -static int pager_playback(Pager *pPager, int isHot){
|
| - sqlite3_vfs *pVfs = pPager->pVfs;
|
| - i64 szJ; /* Size of the journal file in bytes */
|
| - u32 nRec; /* Number of Records in the journal */
|
| - u32 u; /* Unsigned loop counter */
|
| - Pgno mxPg = 0; /* Size of the original file in pages */
|
| - int rc; /* Result code of a subroutine */
|
| - int res = 1; /* Value returned by sqlite3OsAccess() */
|
| - char *zMaster = 0; /* Name of master journal file if any */
|
| - int needPagerReset; /* True to reset page prior to first page rollback */
|
| -
|
| - /* Figure out how many records are in the journal. Abort early if
|
| - ** the journal is empty.
|
| - */
|
| - assert( isOpen(pPager->jfd) );
|
| - rc = sqlite3OsFileSize(pPager->jfd, &szJ);
|
| - if( rc!=SQLITE_OK || szJ==0 ){
|
| - goto end_playback;
|
| - }
|
| -
|
| - /* Read the master journal name from the journal, if it is present.
|
| - ** If a master journal file name is specified, but the file is not
|
| - ** present on disk, then the journal is not hot and does not need to be
|
| - ** played back.
|
| - **
|
| - ** TODO: Technically the following is an error because it assumes that
|
| - ** buffer Pager.pTmpSpace is (mxPathname+1) bytes or larger. i.e. that
|
| - ** (pPager->pageSize >= pPager->pVfs->mxPathname+1). Using os_unix.c,
|
| - ** mxPathname is 512, which is the same as the minimum allowable value
|
| - ** for pageSize.
|
| - */
|
| - zMaster = pPager->pTmpSpace;
|
| - rc = readMasterJournal(pPager->jfd, zMaster, pPager->pVfs->mxPathname+1);
|
| - if( rc==SQLITE_OK && zMaster[0] ){
|
| - rc = sqlite3OsAccess(pVfs, zMaster, SQLITE_ACCESS_EXISTS, &res);
|
| - }
|
| - zMaster = 0;
|
| - if( rc!=SQLITE_OK || !res ){
|
| - goto end_playback;
|
| - }
|
| - pPager->journalOff = 0;
|
| - needPagerReset = isHot;
|
| -
|
| - /* This loop terminates either when a readJournalHdr() or
|
| - ** pager_playback_one_page() call returns SQLITE_DONE or an IO error
|
| - ** occurs.
|
| - */
|
| - while( 1 ){
|
| - int isUnsync = 0;
|
| -
|
| - /* Read the next journal header from the journal file. If there are
|
| - ** not enough bytes left in the journal file for a complete header, or
|
| - ** it is corrupted, then a process must of failed while writing it.
|
| - ** This indicates nothing more needs to be rolled back.
|
| - */
|
| - rc = readJournalHdr(pPager, isHot, szJ, &nRec, &mxPg);
|
| - if( rc!=SQLITE_OK ){
|
| - if( rc==SQLITE_DONE ){
|
| - rc = SQLITE_OK;
|
| - }
|
| - goto end_playback;
|
| - }
|
| -
|
| - /* If nRec is 0xffffffff, then this journal was created by a process
|
| - ** working in no-sync mode. This means that the rest of the journal
|
| - ** file consists of pages, there are no more journal headers. Compute
|
| - ** the value of nRec based on this assumption.
|
| - */
|
| - if( nRec==0xffffffff ){
|
| - assert( pPager->journalOff==JOURNAL_HDR_SZ(pPager) );
|
| - nRec = (int)((szJ - JOURNAL_HDR_SZ(pPager))/JOURNAL_PG_SZ(pPager));
|
| - }
|
| -
|
| - /* If nRec is 0 and this rollback is of a transaction created by this
|
| - ** process and if this is the final header in the journal, then it means
|
| - ** that this part of the journal was being filled but has not yet been
|
| - ** synced to disk. Compute the number of pages based on the remaining
|
| - ** size of the file.
|
| - **
|
| - ** The third term of the test was added to fix ticket #2565.
|
| - ** When rolling back a hot journal, nRec==0 always means that the next
|
| - ** chunk of the journal contains zero pages to be rolled back. But
|
| - ** when doing a ROLLBACK and the nRec==0 chunk is the last chunk in
|
| - ** the journal, it means that the journal might contain additional
|
| - ** pages that need to be rolled back and that the number of pages
|
| - ** should be computed based on the journal file size.
|
| - */
|
| - if( nRec==0 && !isHot &&
|
| - pPager->journalHdr+JOURNAL_HDR_SZ(pPager)==pPager->journalOff ){
|
| - nRec = (int)((szJ - pPager->journalOff) / JOURNAL_PG_SZ(pPager));
|
| - isUnsync = 1;
|
| - }
|
| -
|
| - /* If this is the first header read from the journal, truncate the
|
| - ** database file back to its original size.
|
| - */
|
| - if( pPager->journalOff==JOURNAL_HDR_SZ(pPager) ){
|
| - rc = pager_truncate(pPager, mxPg);
|
| - if( rc!=SQLITE_OK ){
|
| - goto end_playback;
|
| - }
|
| - pPager->dbSize = mxPg;
|
| - }
|
| -
|
| - /* Copy original pages out of the journal and back into the
|
| - ** database file and/or page cache.
|
| - */
|
| - for(u=0; u<nRec; u++){
|
| - if( needPagerReset ){
|
| - pager_reset(pPager);
|
| - needPagerReset = 0;
|
| - }
|
| - rc = pager_playback_one_page(pPager,1,isUnsync,&pPager->journalOff,0,0);
|
| - if( rc!=SQLITE_OK ){
|
| - if( rc==SQLITE_DONE ){
|
| - rc = SQLITE_OK;
|
| - pPager->journalOff = szJ;
|
| - break;
|
| - }else{
|
| - /* If we are unable to rollback, quit and return the error
|
| - ** code. This will cause the pager to enter the error state
|
| - ** so that no further harm will be done. Perhaps the next
|
| - ** process to come along will be able to rollback the database.
|
| - */
|
| - goto end_playback;
|
| - }
|
| - }
|
| - }
|
| - }
|
| - /*NOTREACHED*/
|
| - assert( 0 );
|
| -
|
| -end_playback:
|
| - /* Following a rollback, the database file should be back in its original
|
| - ** state prior to the start of the transaction, so invoke the
|
| - ** SQLITE_FCNTL_DB_UNCHANGED file-control method to disable the
|
| - ** assertion that the transaction counter was modified.
|
| - */
|
| - assert(
|
| - pPager->fd->pMethods==0 ||
|
| - sqlite3OsFileControl(pPager->fd,SQLITE_FCNTL_DB_UNCHANGED,0)>=SQLITE_OK
|
| - );
|
| -
|
| - /* If this playback is happening automatically as a result of an IO or
|
| - ** malloc error that occurred after the change-counter was updated but
|
| - ** before the transaction was committed, then the change-counter
|
| - ** modification may just have been reverted. If this happens in exclusive
|
| - ** mode, then subsequent transactions performed by the connection will not
|
| - ** update the change-counter at all. This may lead to cache inconsistency
|
| - ** problems for other processes at some point in the future. So, just
|
| - ** in case this has happened, clear the changeCountDone flag now.
|
| - */
|
| - pPager->changeCountDone = pPager->tempFile;
|
| -
|
| - if( rc==SQLITE_OK ){
|
| - zMaster = pPager->pTmpSpace;
|
| - rc = readMasterJournal(pPager->jfd, zMaster, pPager->pVfs->mxPathname+1);
|
| - testcase( rc!=SQLITE_OK );
|
| - }
|
| - if( rc==SQLITE_OK ){
|
| - rc = pager_end_transaction(pPager, zMaster[0]!='\0');
|
| - testcase( rc!=SQLITE_OK );
|
| - }
|
| - if( rc==SQLITE_OK && zMaster[0] && res ){
|
| - /* If there was a master journal and this routine will return success,
|
| - ** see if it is possible to delete the master journal.
|
| - */
|
| - rc = pager_delmaster(pPager, zMaster);
|
| - testcase( rc!=SQLITE_OK );
|
| - }
|
| -
|
| - /* The Pager.sectorSize variable may have been updated while rolling
|
| - ** back a journal created by a process with a different sector size
|
| - ** value. Reset it to the correct value for this process.
|
| - */
|
| - setSectorSize(pPager);
|
| - return rc;
|
| -}
|
| -
|
| -/*
|
| -** Playback savepoint pSavepoint. Or, if pSavepoint==NULL, then playback
|
| -** the entire master journal file. The case pSavepoint==NULL occurs when
|
| -** a ROLLBACK TO command is invoked on a SAVEPOINT that is a transaction
|
| -** savepoint.
|
| -**
|
| -** When pSavepoint is not NULL (meaning a non-transaction savepoint is
|
| -** being rolled back), then the rollback consists of up to three stages,
|
| -** performed in the order specified:
|
| -**
|
| -** * Pages are played back from the main journal starting at byte
|
| -** offset PagerSavepoint.iOffset and continuing to
|
| -** PagerSavepoint.iHdrOffset, or to the end of the main journal
|
| -** file if PagerSavepoint.iHdrOffset is zero.
|
| -**
|
| -** * If PagerSavepoint.iHdrOffset is not zero, then pages are played
|
| -** back starting from the journal header immediately following
|
| -** PagerSavepoint.iHdrOffset to the end of the main journal file.
|
| -**
|
| -** * Pages are then played back from the sub-journal file, starting
|
| -** with the PagerSavepoint.iSubRec and continuing to the end of
|
| -** the journal file.
|
| -**
|
| -** Throughout the rollback process, each time a page is rolled back, the
|
| -** corresponding bit is set in a bitvec structure (variable pDone in the
|
| -** implementation below). This is used to ensure that a page is only
|
| -** rolled back the first time it is encountered in either journal.
|
| -**
|
| -** If pSavepoint is NULL, then pages are only played back from the main
|
| -** journal file. There is no need for a bitvec in this case.
|
| -**
|
| -** In either case, before playback commences the Pager.dbSize variable
|
| -** is reset to the value that it held at the start of the savepoint
|
| -** (or transaction). No page with a page-number greater than this value
|
| -** is played back. If one is encountered it is simply skipped.
|
| -*/
|
| -static int pagerPlaybackSavepoint(Pager *pPager, PagerSavepoint *pSavepoint){
|
| - i64 szJ; /* Effective size of the main journal */
|
| - i64 iHdrOff; /* End of first segment of main-journal records */
|
| - int rc = SQLITE_OK; /* Return code */
|
| - Bitvec *pDone = 0; /* Bitvec to ensure pages played back only once */
|
| -
|
| - assert( pPager->state>=PAGER_SHARED );
|
| -
|
| - /* Allocate a bitvec to use to store the set of pages rolled back */
|
| - if( pSavepoint ){
|
| - pDone = sqlite3BitvecCreate(pSavepoint->nOrig);
|
| - if( !pDone ){
|
| - return SQLITE_NOMEM;
|
| - }
|
| - }
|
| -
|
| - /* Set the database size back to the value it was before the savepoint
|
| - ** being reverted was opened.
|
| - */
|
| - pPager->dbSize = pSavepoint ? pSavepoint->nOrig : pPager->dbOrigSize;
|
| -
|
| - /* Use pPager->journalOff as the effective size of the main rollback
|
| - ** journal. The actual file might be larger than this in
|
| - ** PAGER_JOURNALMODE_TRUNCATE or PAGER_JOURNALMODE_PERSIST. But anything
|
| - ** past pPager->journalOff is off-limits to us.
|
| - */
|
| - szJ = pPager->journalOff;
|
| -
|
| - /* Begin by rolling back records from the main journal starting at
|
| - ** PagerSavepoint.iOffset and continuing to the next journal header.
|
| - ** There might be records in the main journal that have a page number
|
| - ** greater than the current database size (pPager->dbSize) but those
|
| - ** will be skipped automatically. Pages are added to pDone as they
|
| - ** are played back.
|
| - */
|
| - if( pSavepoint ){
|
| - iHdrOff = pSavepoint->iHdrOffset ? pSavepoint->iHdrOffset : szJ;
|
| - pPager->journalOff = pSavepoint->iOffset;
|
| - while( rc==SQLITE_OK && pPager->journalOff<iHdrOff ){
|
| - rc = pager_playback_one_page(pPager, 1, 0, &pPager->journalOff, 1, pDone);
|
| - }
|
| - assert( rc!=SQLITE_DONE );
|
| - }else{
|
| - pPager->journalOff = 0;
|
| - }
|
| -
|
| - /* Continue rolling back records out of the main journal starting at
|
| - ** the first journal header seen and continuing until the effective end
|
| - ** of the main journal file. Continue to skip out-of-range pages and
|
| - ** continue adding pages rolled back to pDone.
|
| - */
|
| - while( rc==SQLITE_OK && pPager->journalOff<szJ ){
|
| - u32 ii; /* Loop counter */
|
| - u32 nJRec = 0; /* Number of Journal Records */
|
| - u32 dummy;
|
| - rc = readJournalHdr(pPager, 0, szJ, &nJRec, &dummy);
|
| - assert( rc!=SQLITE_DONE );
|
| -
|
| - /*
|
| - ** The "pPager->journalHdr+JOURNAL_HDR_SZ(pPager)==pPager->journalOff"
|
| - ** test is related to ticket #2565. See the discussion in the
|
| - ** pager_playback() function for additional information.
|
| - */
|
| - if( nJRec==0
|
| - && pPager->journalHdr+JOURNAL_HDR_SZ(pPager)==pPager->journalOff
|
| - ){
|
| - nJRec = (u32)((szJ - pPager->journalOff)/JOURNAL_PG_SZ(pPager));
|
| - }
|
| - for(ii=0; rc==SQLITE_OK && ii<nJRec && pPager->journalOff<szJ; ii++){
|
| - rc = pager_playback_one_page(pPager, 1, 0, &pPager->journalOff, 1, pDone);
|
| - }
|
| - assert( rc!=SQLITE_DONE );
|
| - }
|
| - assert( rc!=SQLITE_OK || pPager->journalOff==szJ );
|
| -
|
| - /* Finally, rollback pages from the sub-journal. Page that were
|
| - ** previously rolled back out of the main journal (and are hence in pDone)
|
| - ** will be skipped. Out-of-range pages are also skipped.
|
| - */
|
| - if( pSavepoint ){
|
| - u32 ii; /* Loop counter */
|
| - i64 offset = pSavepoint->iSubRec*(4+pPager->pageSize);
|
| - for(ii=pSavepoint->iSubRec; rc==SQLITE_OK && ii<pPager->nSubRec; ii++){
|
| - assert( offset==ii*(4+pPager->pageSize) );
|
| - rc = pager_playback_one_page(pPager, 0, 0, &offset, 1, pDone);
|
| - }
|
| - assert( rc!=SQLITE_DONE );
|
| - }
|
| -
|
| - sqlite3BitvecDestroy(pDone);
|
| - if( rc==SQLITE_OK ){
|
| - pPager->journalOff = szJ;
|
| - }
|
| - return rc;
|
| -}
|
| -
|
| -/*
|
| -** Change the maximum number of in-memory pages that are allowed.
|
| -*/
|
| -void sqlite3PagerSetCachesize(Pager *pPager, int mxPage){
|
| - sqlite3PcacheSetCachesize(pPager->pPCache, mxPage);
|
| -}
|
| -
|
| -/*
|
| -** Adjust the robustness of the database to damage due to OS crashes
|
| -** or power failures by changing the number of syncs()s when writing
|
| -** the rollback journal. There are three levels:
|
| -**
|
| -** OFF sqlite3OsSync() is never called. This is the default
|
| -** for temporary and transient files.
|
| -**
|
| -** NORMAL The journal is synced once before writes begin on the
|
| -** database. This is normally adequate protection, but
|
| -** it is theoretically possible, though very unlikely,
|
| -** that an inopertune power failure could leave the journal
|
| -** in a state which would cause damage to the database
|
| -** when it is rolled back.
|
| -**
|
| -** FULL The journal is synced twice before writes begin on the
|
| -** database (with some additional information - the nRec field
|
| -** of the journal header - being written in between the two
|
| -** syncs). If we assume that writing a
|
| -** single disk sector is atomic, then this mode provides
|
| -** assurance that the journal will not be corrupted to the
|
| -** point of causing damage to the database during rollback.
|
| -**
|
| -** Numeric values associated with these states are OFF==1, NORMAL=2,
|
| -** and FULL=3.
|
| -*/
|
| -#ifndef SQLITE_OMIT_PAGER_PRAGMAS
|
| -void sqlite3PagerSetSafetyLevel(Pager *pPager, int level, int bFullFsync){
|
| - pPager->noSync = (level==1 || pPager->tempFile) ?1:0;
|
| - pPager->fullSync = (level==3 && !pPager->tempFile) ?1:0;
|
| - pPager->sync_flags = (bFullFsync?SQLITE_SYNC_FULL:SQLITE_SYNC_NORMAL);
|
| - if( pPager->noSync ) pPager->needSync = 0;
|
| -}
|
| -#endif
|
| -
|
| -/*
|
| -** The following global variable is incremented whenever the library
|
| -** attempts to open a temporary file. This information is used for
|
| -** testing and analysis only.
|
| -*/
|
| -#ifdef SQLITE_TEST
|
| -int sqlite3_opentemp_count = 0;
|
| -#endif
|
| -
|
| -/*
|
| -** Open a temporary file.
|
| -**
|
| -** Write the file descriptor into *pFile. Return SQLITE_OK on success
|
| -** or some other error code if we fail. The OS will automatically
|
| -** delete the temporary file when it is closed.
|
| -**
|
| -** The flags passed to the VFS layer xOpen() call are those specified
|
| -** by parameter vfsFlags ORed with the following:
|
| -**
|
| -** SQLITE_OPEN_READWRITE
|
| -** SQLITE_OPEN_CREATE
|
| -** SQLITE_OPEN_EXCLUSIVE
|
| -** SQLITE_OPEN_DELETEONCLOSE
|
| -*/
|
| -static int pagerOpentemp(
|
| - Pager *pPager, /* The pager object */
|
| - sqlite3_file *pFile, /* Write the file descriptor here */
|
| - int vfsFlags /* Flags passed through to the VFS */
|
| -){
|
| - int rc; /* Return code */
|
| -
|
| -#ifdef SQLITE_TEST
|
| - sqlite3_opentemp_count++; /* Used for testing and analysis only */
|
| -#endif
|
| -
|
| - vfsFlags |= SQLITE_OPEN_READWRITE | SQLITE_OPEN_CREATE |
|
| - SQLITE_OPEN_EXCLUSIVE | SQLITE_OPEN_DELETEONCLOSE;
|
| - rc = sqlite3OsOpen(pPager->pVfs, 0, pFile, vfsFlags, 0);
|
| - assert( rc!=SQLITE_OK || isOpen(pFile) );
|
| - return rc;
|
| -}
|
| -
|
| -/*
|
| -** Set the busy handler function.
|
| -**
|
| -** The pager invokes the busy-handler if sqlite3OsLock() returns
|
| -** SQLITE_BUSY when trying to upgrade from no-lock to a SHARED lock,
|
| -** or when trying to upgrade from a RESERVED lock to an EXCLUSIVE
|
| -** lock. It does *not* invoke the busy handler when upgrading from
|
| -** SHARED to RESERVED, or when upgrading from SHARED to EXCLUSIVE
|
| -** (which occurs during hot-journal rollback). Summary:
|
| -**
|
| -** Transition | Invokes xBusyHandler
|
| -** --------------------------------------------------------
|
| -** NO_LOCK -> SHARED_LOCK | Yes
|
| -** SHARED_LOCK -> RESERVED_LOCK | No
|
| -** SHARED_LOCK -> EXCLUSIVE_LOCK | No
|
| -** RESERVED_LOCK -> EXCLUSIVE_LOCK | Yes
|
| -**
|
| -** If the busy-handler callback returns non-zero, the lock is
|
| -** retried. If it returns zero, then the SQLITE_BUSY error is
|
| -** returned to the caller of the pager API function.
|
| -*/
|
| -void sqlite3PagerSetBusyhandler(
|
| - Pager *pPager, /* Pager object */
|
| - int (*xBusyHandler)(void *), /* Pointer to busy-handler function */
|
| - void *pBusyHandlerArg /* Argument to pass to xBusyHandler */
|
| -){
|
| - pPager->xBusyHandler = xBusyHandler;
|
| - pPager->pBusyHandlerArg = pBusyHandlerArg;
|
| -}
|
| -
|
| -/*
|
| -** Report the current page size and number of reserved bytes back
|
| -** to the codec.
|
| -*/
|
| -#ifdef SQLITE_HAS_CODEC
|
| -static void pagerReportSize(Pager *pPager){
|
| - if( pPager->xCodecSizeChng ){
|
| - pPager->xCodecSizeChng(pPager->pCodec, pPager->pageSize,
|
| - (int)pPager->nReserve);
|
| - }
|
| -}
|
| -#else
|
| -# define pagerReportSize(X) /* No-op if we do not support a codec */
|
| -#endif
|
| -
|
| -/*
|
| -** Change the page size used by the Pager object. The new page size
|
| -** is passed in *pPageSize.
|
| -**
|
| -** If the pager is in the error state when this function is called, it
|
| -** is a no-op. The value returned is the error state error code (i.e.
|
| -** one of SQLITE_IOERR, SQLITE_CORRUPT or SQLITE_FULL).
|
| -**
|
| -** Otherwise, if all of the following are true:
|
| -**
|
| -** * the new page size (value of *pPageSize) is valid (a power
|
| -** of two between 512 and SQLITE_MAX_PAGE_SIZE, inclusive), and
|
| -**
|
| -** * there are no outstanding page references, and
|
| -**
|
| -** * the database is either not an in-memory database or it is
|
| -** an in-memory database that currently consists of zero pages.
|
| -**
|
| -** then the pager object page size is set to *pPageSize.
|
| -**
|
| -** If the page size is changed, then this function uses sqlite3PagerMalloc()
|
| -** to obtain a new Pager.pTmpSpace buffer. If this allocation attempt
|
| -** fails, SQLITE_NOMEM is returned and the page size remains unchanged.
|
| -** In all other cases, SQLITE_OK is returned.
|
| -**
|
| -** If the page size is not changed, either because one of the enumerated
|
| -** conditions above is not true, the pager was in error state when this
|
| -** function was called, or because the memory allocation attempt failed,
|
| -** then *pPageSize is set to the old, retained page size before returning.
|
| -*/
|
| -int sqlite3PagerSetPagesize(Pager *pPager, u16 *pPageSize, int nReserve){
|
| - int rc = pPager->errCode;
|
| -
|
| - if( rc==SQLITE_OK ){
|
| - u16 pageSize = *pPageSize;
|
| - assert( pageSize==0 || (pageSize>=512 && pageSize<=SQLITE_MAX_PAGE_SIZE) );
|
| - if( (pPager->memDb==0 || pPager->dbSize==0)
|
| - && sqlite3PcacheRefCount(pPager->pPCache)==0
|
| - && pageSize && pageSize!=pPager->pageSize
|
| - ){
|
| - char *pNew = (char *)sqlite3PageMalloc(pageSize);
|
| - if( !pNew ){
|
| - rc = SQLITE_NOMEM;
|
| - }else{
|
| - pager_reset(pPager);
|
| - pPager->pageSize = pageSize;
|
| - sqlite3PageFree(pPager->pTmpSpace);
|
| - pPager->pTmpSpace = pNew;
|
| - sqlite3PcacheSetPageSize(pPager->pPCache, pageSize);
|
| - }
|
| - }
|
| - *pPageSize = (u16)pPager->pageSize;
|
| - if( nReserve<0 ) nReserve = pPager->nReserve;
|
| - assert( nReserve>=0 && nReserve<1000 );
|
| - pPager->nReserve = (i16)nReserve;
|
| - pagerReportSize(pPager);
|
| - }
|
| - return rc;
|
| -}
|
| -
|
| -/*
|
| -** Return a pointer to the "temporary page" buffer held internally
|
| -** by the pager. This is a buffer that is big enough to hold the
|
| -** entire content of a database page. This buffer is used internally
|
| -** during rollback and will be overwritten whenever a rollback
|
| -** occurs. But other modules are free to use it too, as long as
|
| -** no rollbacks are happening.
|
| -*/
|
| -void *sqlite3PagerTempSpace(Pager *pPager){
|
| - return pPager->pTmpSpace;
|
| -}
|
| -
|
| -/*
|
| -** Attempt to set the maximum database page count if mxPage is positive.
|
| -** Make no changes if mxPage is zero or negative. And never reduce the
|
| -** maximum page count below the current size of the database.
|
| -**
|
| -** Regardless of mxPage, return the current maximum page count.
|
| -*/
|
| -int sqlite3PagerMaxPageCount(Pager *pPager, int mxPage){
|
| - if( mxPage>0 ){
|
| - pPager->mxPgno = mxPage;
|
| - }
|
| - sqlite3PagerPagecount(pPager, 0);
|
| - return pPager->mxPgno;
|
| -}
|
| -
|
| -/*
|
| -** The following set of routines are used to disable the simulated
|
| -** I/O error mechanism. These routines are used to avoid simulated
|
| -** errors in places where we do not care about errors.
|
| -**
|
| -** Unless -DSQLITE_TEST=1 is used, these routines are all no-ops
|
| -** and generate no code.
|
| -*/
|
| -#ifdef SQLITE_TEST
|
| -extern int sqlite3_io_error_pending;
|
| -extern int sqlite3_io_error_hit;
|
| -static int saved_cnt;
|
| -void disable_simulated_io_errors(void){
|
| - saved_cnt = sqlite3_io_error_pending;
|
| - sqlite3_io_error_pending = -1;
|
| -}
|
| -void enable_simulated_io_errors(void){
|
| - sqlite3_io_error_pending = saved_cnt;
|
| -}
|
| -#else
|
| -# define disable_simulated_io_errors()
|
| -# define enable_simulated_io_errors()
|
| -#endif
|
| -
|
| -/*
|
| -** Read the first N bytes from the beginning of the file into memory
|
| -** that pDest points to.
|
| -**
|
| -** If the pager was opened on a transient file (zFilename==""), or
|
| -** opened on a file less than N bytes in size, the output buffer is
|
| -** zeroed and SQLITE_OK returned. The rationale for this is that this
|
| -** function is used to read database headers, and a new transient or
|
| -** zero sized database has a header than consists entirely of zeroes.
|
| -**
|
| -** If any IO error apart from SQLITE_IOERR_SHORT_READ is encountered,
|
| -** the error code is returned to the caller and the contents of the
|
| -** output buffer undefined.
|
| -*/
|
| -int sqlite3PagerReadFileheader(Pager *pPager, int N, unsigned char *pDest){
|
| - int rc = SQLITE_OK;
|
| - memset(pDest, 0, N);
|
| - assert( isOpen(pPager->fd) || pPager->tempFile );
|
| - if( isOpen(pPager->fd) ){
|
| - IOTRACE(("DBHDR %p 0 %d\n", pPager, N))
|
| - rc = sqlite3OsRead(pPager->fd, pDest, N, 0);
|
| - if( rc==SQLITE_IOERR_SHORT_READ ){
|
| - rc = SQLITE_OK;
|
| - }
|
| - }
|
| - return rc;
|
| -}
|
| -
|
| -/*
|
| -** Return the total number of pages in the database file associated
|
| -** with pPager. Normally, this is calculated as (<db file size>/<page-size>).
|
| -** However, if the file is between 1 and <page-size> bytes in size, then
|
| -** this is considered a 1 page file.
|
| -**
|
| -** If the pager is in error state when this function is called, then the
|
| -** error state error code is returned and *pnPage left unchanged. Or,
|
| -** if the file system has to be queried for the size of the file and
|
| -** the query attempt returns an IO error, the IO error code is returned
|
| -** and *pnPage is left unchanged.
|
| -**
|
| -** Otherwise, if everything is successful, then SQLITE_OK is returned
|
| -** and *pnPage is set to the number of pages in the database.
|
| -*/
|
| -int sqlite3PagerPagecount(Pager *pPager, int *pnPage){
|
| - Pgno nPage; /* Value to return via *pnPage */
|
| -
|
| - /* If the pager is already in the error state, return the error code. */
|
| - if( pPager->errCode ){
|
| - return pPager->errCode;
|
| - }
|
| -
|
| - /* Determine the number of pages in the file. Store this in nPage. */
|
| - if( pPager->dbSizeValid ){
|
| - nPage = pPager->dbSize;
|
| - }else{
|
| - int rc; /* Error returned by OsFileSize() */
|
| - i64 n = 0; /* File size in bytes returned by OsFileSize() */
|
| -
|
| - assert( isOpen(pPager->fd) || pPager->tempFile );
|
| - if( isOpen(pPager->fd) && (0 != (rc = sqlite3OsFileSize(pPager->fd, &n))) ){
|
| - pager_error(pPager, rc);
|
| - return rc;
|
| - }
|
| - if( n>0 && n<pPager->pageSize ){
|
| - nPage = 1;
|
| - }else{
|
| - nPage = (Pgno)(n / pPager->pageSize);
|
| - }
|
| - if( pPager->state!=PAGER_UNLOCK ){
|
| - pPager->dbSize = nPage;
|
| - pPager->dbFileSize = nPage;
|
| - pPager->dbSizeValid = 1;
|
| - }
|
| - }
|
| -
|
| - /* If the current number of pages in the file is greater than the
|
| - ** configured maximum pager number, increase the allowed limit so
|
| - ** that the file can be read.
|
| - */
|
| - if( nPage>pPager->mxPgno ){
|
| - pPager->mxPgno = (Pgno)nPage;
|
| - }
|
| -
|
| - /* Set the output variable and return SQLITE_OK */
|
| - if( pnPage ){
|
| - *pnPage = nPage;
|
| - }
|
| - return SQLITE_OK;
|
| -}
|
| -
|
| -
|
| -/*
|
| -** Try to obtain a lock of type locktype on the database file. If
|
| -** a similar or greater lock is already held, this function is a no-op
|
| -** (returning SQLITE_OK immediately).
|
| -**
|
| -** Otherwise, attempt to obtain the lock using sqlite3OsLock(). Invoke
|
| -** the busy callback if the lock is currently not available. Repeat
|
| -** until the busy callback returns false or until the attempt to
|
| -** obtain the lock succeeds.
|
| -**
|
| -** Return SQLITE_OK on success and an error code if we cannot obtain
|
| -** the lock. If the lock is obtained successfully, set the Pager.state
|
| -** variable to locktype before returning.
|
| -*/
|
| -static int pager_wait_on_lock(Pager *pPager, int locktype){
|
| - int rc; /* Return code */
|
| -
|
| - /* The OS lock values must be the same as the Pager lock values */
|
| - assert( PAGER_SHARED==SHARED_LOCK );
|
| - assert( PAGER_RESERVED==RESERVED_LOCK );
|
| - assert( PAGER_EXCLUSIVE==EXCLUSIVE_LOCK );
|
| -
|
| - /* If the file is currently unlocked then the size must be unknown */
|
| - assert( pPager->state>=PAGER_SHARED || pPager->dbSizeValid==0 );
|
| -
|
| - /* Check that this is either a no-op (because the requested lock is
|
| - ** already held, or one of the transistions that the busy-handler
|
| - ** may be invoked during, according to the comment above
|
| - ** sqlite3PagerSetBusyhandler().
|
| - */
|
| - assert( (pPager->state>=locktype)
|
| - || (pPager->state==PAGER_UNLOCK && locktype==PAGER_SHARED)
|
| - || (pPager->state==PAGER_RESERVED && locktype==PAGER_EXCLUSIVE)
|
| - );
|
| -
|
| - if( pPager->state>=locktype ){
|
| - rc = SQLITE_OK;
|
| - }else{
|
| - do {
|
| - rc = sqlite3OsLock(pPager->fd, locktype);
|
| - }while( rc==SQLITE_BUSY && pPager->xBusyHandler(pPager->pBusyHandlerArg) );
|
| - if( rc==SQLITE_OK ){
|
| - pPager->state = (u8)locktype;
|
| - IOTRACE(("LOCK %p %d\n", pPager, locktype))
|
| - }
|
| - }
|
| - return rc;
|
| -}
|
| -
|
| -/*
|
| -** Function assertTruncateConstraint(pPager) checks that one of the
|
| -** following is true for all dirty pages currently in the page-cache:
|
| -**
|
| -** a) The page number is less than or equal to the size of the
|
| -** current database image, in pages, OR
|
| -**
|
| -** b) if the page content were written at this time, it would not
|
| -** be necessary to write the current content out to the sub-journal
|
| -** (as determined by function subjRequiresPage()).
|
| -**
|
| -** If the condition asserted by this function were not true, and the
|
| -** dirty page were to be discarded from the cache via the pagerStress()
|
| -** routine, pagerStress() would not write the current page content to
|
| -** the database file. If a savepoint transaction were rolled back after
|
| -** this happened, the correct behaviour would be to restore the current
|
| -** content of the page. However, since this content is not present in either
|
| -** the database file or the portion of the rollback journal and
|
| -** sub-journal rolled back the content could not be restored and the
|
| -** database image would become corrupt. It is therefore fortunate that
|
| -** this circumstance cannot arise.
|
| -*/
|
| -#if defined(SQLITE_DEBUG)
|
| -static void assertTruncateConstraintCb(PgHdr *pPg){
|
| - assert( pPg->flags&PGHDR_DIRTY );
|
| - assert( !subjRequiresPage(pPg) || pPg->pgno<=pPg->pPager->dbSize );
|
| -}
|
| -static void assertTruncateConstraint(Pager *pPager){
|
| - sqlite3PcacheIterateDirty(pPager->pPCache, assertTruncateConstraintCb);
|
| -}
|
| -#else
|
| -# define assertTruncateConstraint(pPager)
|
| -#endif
|
| -
|
| -/*
|
| -** Truncate the in-memory database file image to nPage pages. This
|
| -** function does not actually modify the database file on disk. It
|
| -** just sets the internal state of the pager object so that the
|
| -** truncation will be done when the current transaction is committed.
|
| -*/
|
| -void sqlite3PagerTruncateImage(Pager *pPager, Pgno nPage){
|
| - assert( pPager->dbSizeValid );
|
| - assert( pPager->dbSize>=nPage );
|
| - assert( pPager->state>=PAGER_RESERVED );
|
| - pPager->dbSize = nPage;
|
| - assertTruncateConstraint(pPager);
|
| -}
|
| -
|
| -/*
|
| -** Shutdown the page cache. Free all memory and close all files.
|
| -**
|
| -** If a transaction was in progress when this routine is called, that
|
| -** transaction is rolled back. All outstanding pages are invalidated
|
| -** and their memory is freed. Any attempt to use a page associated
|
| -** with this page cache after this function returns will likely
|
| -** result in a coredump.
|
| -**
|
| -** This function always succeeds. If a transaction is active an attempt
|
| -** is made to roll it back. If an error occurs during the rollback
|
| -** a hot journal may be left in the filesystem but no error is returned
|
| -** to the caller.
|
| -*/
|
| -int sqlite3PagerClose(Pager *pPager){
|
| - disable_simulated_io_errors();
|
| - sqlite3BeginBenignMalloc();
|
| - pPager->errCode = 0;
|
| - pPager->exclusiveMode = 0;
|
| - pager_reset(pPager);
|
| - if( MEMDB ){
|
| - pager_unlock(pPager);
|
| - }else{
|
| - /* Set Pager.journalHdr to -1 for the benefit of the pager_playback()
|
| - ** call which may be made from within pagerUnlockAndRollback(). If it
|
| - ** is not -1, then the unsynced portion of an open journal file may
|
| - ** be played back into the database. If a power failure occurs while
|
| - ** this is happening, the database may become corrupt.
|
| - */
|
| - pPager->journalHdr = -1;
|
| - pagerUnlockAndRollback(pPager);
|
| - }
|
| - sqlite3EndBenignMalloc();
|
| - enable_simulated_io_errors();
|
| - PAGERTRACE(("CLOSE %d\n", PAGERID(pPager)));
|
| - IOTRACE(("CLOSE %p\n", pPager))
|
| - sqlite3OsClose(pPager->fd);
|
| - sqlite3PageFree(pPager->pTmpSpace);
|
| - sqlite3PcacheClose(pPager->pPCache);
|
| -
|
| -#ifdef SQLITE_HAS_CODEC
|
| - if( pPager->xCodecFree ) pPager->xCodecFree(pPager->pCodec);
|
| -#endif
|
| -
|
| - assert( !pPager->aSavepoint && !pPager->pInJournal );
|
| - assert( !isOpen(pPager->jfd) && !isOpen(pPager->sjfd) );
|
| -
|
| - sqlite3_free(pPager);
|
| - return SQLITE_OK;
|
| -}
|
| -
|
| -#if !defined(NDEBUG) || defined(SQLITE_TEST)
|
| -/*
|
| -** Return the page number for page pPg.
|
| -*/
|
| -Pgno sqlite3PagerPagenumber(DbPage *pPg){
|
| - return pPg->pgno;
|
| -}
|
| -#endif
|
| -
|
| -/*
|
| -** Increment the reference count for page pPg.
|
| -*/
|
| -void sqlite3PagerRef(DbPage *pPg){
|
| - sqlite3PcacheRef(pPg);
|
| -}
|
| -
|
| -/*
|
| -** Sync the journal. In other words, make sure all the pages that have
|
| -** been written to the journal have actually reached the surface of the
|
| -** disk and can be restored in the event of a hot-journal rollback.
|
| -**
|
| -** If the Pager.needSync flag is not set, then this function is a
|
| -** no-op. Otherwise, the actions required depend on the journal-mode
|
| -** and the device characteristics of the the file-system, as follows:
|
| -**
|
| -** * If the journal file is an in-memory journal file, no action need
|
| -** be taken.
|
| -**
|
| -** * Otherwise, if the device does not support the SAFE_APPEND property,
|
| -** then the nRec field of the most recently written journal header
|
| -** is updated to contain the number of journal records that have
|
| -** been written following it. If the pager is operating in full-sync
|
| -** mode, then the journal file is synced before this field is updated.
|
| -**
|
| -** * If the device does not support the SEQUENTIAL property, then
|
| -** journal file is synced.
|
| -**
|
| -** Or, in pseudo-code:
|
| -**
|
| -** if( NOT <in-memory journal> ){
|
| -** if( NOT SAFE_APPEND ){
|
| -** if( <full-sync mode> ) xSync(<journal file>);
|
| -** <update nRec field>
|
| -** }
|
| -** if( NOT SEQUENTIAL ) xSync(<journal file>);
|
| -** }
|
| -**
|
| -** The Pager.needSync flag is never be set for temporary files, or any
|
| -** file operating in no-sync mode (Pager.noSync set to non-zero).
|
| -**
|
| -** If successful, this routine clears the PGHDR_NEED_SYNC flag of every
|
| -** page currently held in memory before returning SQLITE_OK. If an IO
|
| -** error is encountered, then the IO error code is returned to the caller.
|
| -*/
|
| -static int syncJournal(Pager *pPager){
|
| - if( pPager->needSync ){
|
| - assert( !pPager->tempFile );
|
| - if( pPager->journalMode!=PAGER_JOURNALMODE_MEMORY ){
|
| - int rc; /* Return code */
|
| - const int iDc = sqlite3OsDeviceCharacteristics(pPager->fd);
|
| - assert( isOpen(pPager->jfd) );
|
| -
|
| - if( 0==(iDc&SQLITE_IOCAP_SAFE_APPEND) ){
|
| - /* This block deals with an obscure problem. If the last connection
|
| - ** that wrote to this database was operating in persistent-journal
|
| - ** mode, then the journal file may at this point actually be larger
|
| - ** than Pager.journalOff bytes. If the next thing in the journal
|
| - ** file happens to be a journal-header (written as part of the
|
| - ** previous connections transaction), and a crash or power-failure
|
| - ** occurs after nRec is updated but before this connection writes
|
| - ** anything else to the journal file (or commits/rolls back its
|
| - ** transaction), then SQLite may become confused when doing the
|
| - ** hot-journal rollback following recovery. It may roll back all
|
| - ** of this connections data, then proceed to rolling back the old,
|
| - ** out-of-date data that follows it. Database corruption.
|
| - **
|
| - ** To work around this, if the journal file does appear to contain
|
| - ** a valid header following Pager.journalOff, then write a 0x00
|
| - ** byte to the start of it to prevent it from being recognized.
|
| - **
|
| - ** Variable iNextHdrOffset is set to the offset at which this
|
| - ** problematic header will occur, if it exists. aMagic is used
|
| - ** as a temporary buffer to inspect the first couple of bytes of
|
| - ** the potential journal header.
|
| - */
|
| - i64 iNextHdrOffset;
|
| - u8 aMagic[8];
|
| - u8 zHeader[sizeof(aJournalMagic)+4];
|
| -
|
| - memcpy(zHeader, aJournalMagic, sizeof(aJournalMagic));
|
| - put32bits(&zHeader[sizeof(aJournalMagic)], pPager->nRec);
|
| -
|
| - iNextHdrOffset = journalHdrOffset(pPager);
|
| - rc = sqlite3OsRead(pPager->jfd, aMagic, 8, iNextHdrOffset);
|
| - if( rc==SQLITE_OK && 0==memcmp(aMagic, aJournalMagic, 8) ){
|
| - static const u8 zerobyte = 0;
|
| - rc = sqlite3OsWrite(pPager->jfd, &zerobyte, 1, iNextHdrOffset);
|
| - }
|
| - if( rc!=SQLITE_OK && rc!=SQLITE_IOERR_SHORT_READ ){
|
| - return rc;
|
| - }
|
| -
|
| - /* Write the nRec value into the journal file header. If in
|
| - ** full-synchronous mode, sync the journal first. This ensures that
|
| - ** all data has really hit the disk before nRec is updated to mark
|
| - ** it as a candidate for rollback.
|
| - **
|
| - ** This is not required if the persistent media supports the
|
| - ** SAFE_APPEND property. Because in this case it is not possible
|
| - ** for garbage data to be appended to the file, the nRec field
|
| - ** is populated with 0xFFFFFFFF when the journal header is written
|
| - ** and never needs to be updated.
|
| - */
|
| - if( pPager->fullSync && 0==(iDc&SQLITE_IOCAP_SEQUENTIAL) ){
|
| - PAGERTRACE(("SYNC journal of %d\n", PAGERID(pPager)));
|
| - IOTRACE(("JSYNC %p\n", pPager))
|
| - rc = sqlite3OsSync(pPager->jfd, pPager->sync_flags);
|
| - if( rc!=SQLITE_OK ) return rc;
|
| - }
|
| - IOTRACE(("JHDR %p %lld\n", pPager, pPager->journalHdr));
|
| - rc = sqlite3OsWrite(
|
| - pPager->jfd, zHeader, sizeof(zHeader), pPager->journalHdr
|
| - );
|
| - if( rc!=SQLITE_OK ) return rc;
|
| - }
|
| - if( 0==(iDc&SQLITE_IOCAP_SEQUENTIAL) ){
|
| - PAGERTRACE(("SYNC journal of %d\n", PAGERID(pPager)));
|
| - IOTRACE(("JSYNC %p\n", pPager))
|
| - rc = sqlite3OsSync(pPager->jfd, pPager->sync_flags|
|
| - (pPager->sync_flags==SQLITE_SYNC_FULL?SQLITE_SYNC_DATAONLY:0)
|
| - );
|
| - if( rc!=SQLITE_OK ) return rc;
|
| - }
|
| - }
|
| -
|
| - /* The journal file was just successfully synced. Set Pager.needSync
|
| - ** to zero and clear the PGHDR_NEED_SYNC flag on all pagess.
|
| - */
|
| - pPager->needSync = 0;
|
| - pPager->journalStarted = 1;
|
| - sqlite3PcacheClearSyncFlags(pPager->pPCache);
|
| - }
|
| -
|
| - return SQLITE_OK;
|
| -}
|
| -
|
| -/*
|
| -** The argument is the first in a linked list of dirty pages connected
|
| -** by the PgHdr.pDirty pointer. This function writes each one of the
|
| -** in-memory pages in the list to the database file. The argument may
|
| -** be NULL, representing an empty list. In this case this function is
|
| -** a no-op.
|
| -**
|
| -** The pager must hold at least a RESERVED lock when this function
|
| -** is called. Before writing anything to the database file, this lock
|
| -** is upgraded to an EXCLUSIVE lock. If the lock cannot be obtained,
|
| -** SQLITE_BUSY is returned and no data is written to the database file.
|
| -**
|
| -** If the pager is a temp-file pager and the actual file-system file
|
| -** is not yet open, it is created and opened before any data is
|
| -** written out.
|
| -**
|
| -** Once the lock has been upgraded and, if necessary, the file opened,
|
| -** the pages are written out to the database file in list order. Writing
|
| -** a page is skipped if it meets either of the following criteria:
|
| -**
|
| -** * The page number is greater than Pager.dbSize, or
|
| -** * The PGHDR_DONT_WRITE flag is set on the page.
|
| -**
|
| -** If writing out a page causes the database file to grow, Pager.dbFileSize
|
| -** is updated accordingly. If page 1 is written out, then the value cached
|
| -** in Pager.dbFileVers[] is updated to match the new value stored in
|
| -** the database file.
|
| -**
|
| -** If everything is successful, SQLITE_OK is returned. If an IO error
|
| -** occurs, an IO error code is returned. Or, if the EXCLUSIVE lock cannot
|
| -** be obtained, SQLITE_BUSY is returned.
|
| -*/
|
| -static int pager_write_pagelist(PgHdr *pList){
|
| - Pager *pPager; /* Pager object */
|
| - int rc; /* Return code */
|
| -
|
| - if( NEVER(pList==0) ) return SQLITE_OK;
|
| - pPager = pList->pPager;
|
| -
|
| - /* At this point there may be either a RESERVED or EXCLUSIVE lock on the
|
| - ** database file. If there is already an EXCLUSIVE lock, the following
|
| - ** call is a no-op.
|
| - **
|
| - ** Moving the lock from RESERVED to EXCLUSIVE actually involves going
|
| - ** through an intermediate state PENDING. A PENDING lock prevents new
|
| - ** readers from attaching to the database but is unsufficient for us to
|
| - ** write. The idea of a PENDING lock is to prevent new readers from
|
| - ** coming in while we wait for existing readers to clear.
|
| - **
|
| - ** While the pager is in the RESERVED state, the original database file
|
| - ** is unchanged and we can rollback without having to playback the
|
| - ** journal into the original database file. Once we transition to
|
| - ** EXCLUSIVE, it means the database file has been changed and any rollback
|
| - ** will require a journal playback.
|
| - */
|
| - assert( pPager->state>=PAGER_RESERVED );
|
| - rc = pager_wait_on_lock(pPager, EXCLUSIVE_LOCK);
|
| -
|
| - /* If the file is a temp-file has not yet been opened, open it now. It
|
| - ** is not possible for rc to be other than SQLITE_OK if this branch
|
| - ** is taken, as pager_wait_on_lock() is a no-op for temp-files.
|
| - */
|
| - if( !isOpen(pPager->fd) ){
|
| - assert( pPager->tempFile && rc==SQLITE_OK );
|
| - rc = pagerOpentemp(pPager, pPager->fd, pPager->vfsFlags);
|
| - }
|
| -
|
| - while( rc==SQLITE_OK && pList ){
|
| - Pgno pgno = pList->pgno;
|
| -
|
| - /* If there are dirty pages in the page cache with page numbers greater
|
| - ** than Pager.dbSize, this means sqlite3PagerTruncateImage() was called to
|
| - ** make the file smaller (presumably by auto-vacuum code). Do not write
|
| - ** any such pages to the file.
|
| - **
|
| - ** Also, do not write out any page that has the PGHDR_DONT_WRITE flag
|
| - ** set (set by sqlite3PagerDontWrite()).
|
| - */
|
| - if( pgno<=pPager->dbSize && 0==(pList->flags&PGHDR_DONT_WRITE) ){
|
| - i64 offset = (pgno-1)*(i64)pPager->pageSize; /* Offset to write */
|
| - char *pData; /* Data to write */
|
| -
|
| - /* Encode the database */
|
| - CODEC2(pPager, pList->pData, pgno, 6, return SQLITE_NOMEM, pData);
|
| -
|
| - /* Write out the page data. */
|
| - rc = sqlite3OsWrite(pPager->fd, pData, pPager->pageSize, offset);
|
| -
|
| - /* If page 1 was just written, update Pager.dbFileVers to match
|
| - ** the value now stored in the database file. If writing this
|
| - ** page caused the database file to grow, update dbFileSize.
|
| - */
|
| - if( pgno==1 ){
|
| - memcpy(&pPager->dbFileVers, &pData[24], sizeof(pPager->dbFileVers));
|
| - }
|
| - if( pgno>pPager->dbFileSize ){
|
| - pPager->dbFileSize = pgno;
|
| - }
|
| -
|
| - /* Update any backup objects copying the contents of this pager. */
|
| - sqlite3BackupUpdate(pPager->pBackup, pgno, (u8*)pList->pData);
|
| -
|
| - PAGERTRACE(("STORE %d page %d hash(%08x)\n",
|
| - PAGERID(pPager), pgno, pager_pagehash(pList)));
|
| - IOTRACE(("PGOUT %p %d\n", pPager, pgno));
|
| - PAGER_INCR(sqlite3_pager_writedb_count);
|
| - PAGER_INCR(pPager->nWrite);
|
| - }else{
|
| - PAGERTRACE(("NOSTORE %d page %d\n", PAGERID(pPager), pgno));
|
| - }
|
| -#ifdef SQLITE_CHECK_PAGES
|
| - pList->pageHash = pager_pagehash(pList);
|
| -#endif
|
| - pList = pList->pDirty;
|
| - }
|
| -
|
| - return rc;
|
| -}
|
| -
|
| -/*
|
| -** Append a record of the current state of page pPg to the sub-journal.
|
| -** It is the callers responsibility to use subjRequiresPage() to check
|
| -** that it is really required before calling this function.
|
| -**
|
| -** If successful, set the bit corresponding to pPg->pgno in the bitvecs
|
| -** for all open savepoints before returning.
|
| -**
|
| -** This function returns SQLITE_OK if everything is successful, an IO
|
| -** error code if the attempt to write to the sub-journal fails, or
|
| -** SQLITE_NOMEM if a malloc fails while setting a bit in a savepoint
|
| -** bitvec.
|
| -*/
|
| -static int subjournalPage(PgHdr *pPg){
|
| - int rc = SQLITE_OK;
|
| - Pager *pPager = pPg->pPager;
|
| - if( isOpen(pPager->sjfd) ){
|
| - void *pData = pPg->pData;
|
| - i64 offset = pPager->nSubRec*(4+pPager->pageSize);
|
| - char *pData2;
|
| -
|
| - CODEC2(pPager, pData, pPg->pgno, 7, return SQLITE_NOMEM, pData2);
|
| - PAGERTRACE(("STMT-JOURNAL %d page %d\n", PAGERID(pPager), pPg->pgno));
|
| -
|
| - assert( pageInJournal(pPg) || pPg->pgno>pPager->dbOrigSize );
|
| - rc = write32bits(pPager->sjfd, offset, pPg->pgno);
|
| - if( rc==SQLITE_OK ){
|
| - rc = sqlite3OsWrite(pPager->sjfd, pData2, pPager->pageSize, offset+4);
|
| - }
|
| - }
|
| - if( rc==SQLITE_OK ){
|
| - pPager->nSubRec++;
|
| - assert( pPager->nSavepoint>0 );
|
| - rc = addToSavepointBitvecs(pPager, pPg->pgno);
|
| - }
|
| - return rc;
|
| -}
|
| -
|
| -
|
| -/*
|
| -** This function is called by the pcache layer when it has reached some
|
| -** soft memory limit. The first argument is a pointer to a Pager object
|
| -** (cast as a void*). The pager is always 'purgeable' (not an in-memory
|
| -** database). The second argument is a reference to a page that is
|
| -** currently dirty but has no outstanding references. The page
|
| -** is always associated with the Pager object passed as the first
|
| -** argument.
|
| -**
|
| -** The job of this function is to make pPg clean by writing its contents
|
| -** out to the database file, if possible. This may involve syncing the
|
| -** journal file.
|
| -**
|
| -** If successful, sqlite3PcacheMakeClean() is called on the page and
|
| -** SQLITE_OK returned. If an IO error occurs while trying to make the
|
| -** page clean, the IO error code is returned. If the page cannot be
|
| -** made clean for some other reason, but no error occurs, then SQLITE_OK
|
| -** is returned by sqlite3PcacheMakeClean() is not called.
|
| -*/
|
| -static int pagerStress(void *p, PgHdr *pPg){
|
| - Pager *pPager = (Pager *)p;
|
| - int rc = SQLITE_OK;
|
| -
|
| - assert( pPg->pPager==pPager );
|
| - assert( pPg->flags&PGHDR_DIRTY );
|
| -
|
| - /* The doNotSync flag is set by the sqlite3PagerWrite() function while it
|
| - ** is journalling a set of two or more database pages that are stored
|
| - ** on the same disk sector. Syncing the journal is not allowed while
|
| - ** this is happening as it is important that all members of such a
|
| - ** set of pages are synced to disk together. So, if the page this function
|
| - ** is trying to make clean will require a journal sync and the doNotSync
|
| - ** flag is set, return without doing anything. The pcache layer will
|
| - ** just have to go ahead and allocate a new page buffer instead of
|
| - ** reusing pPg.
|
| - **
|
| - ** Similarly, if the pager has already entered the error state, do not
|
| - ** try to write the contents of pPg to disk.
|
| - */
|
| - if( NEVER(pPager->errCode)
|
| - || (pPager->doNotSync && pPg->flags&PGHDR_NEED_SYNC)
|
| - ){
|
| - return SQLITE_OK;
|
| - }
|
| -
|
| - /* Sync the journal file if required. */
|
| - if( pPg->flags&PGHDR_NEED_SYNC ){
|
| - rc = syncJournal(pPager);
|
| - if( rc==SQLITE_OK && pPager->fullSync &&
|
| - !(pPager->journalMode==PAGER_JOURNALMODE_MEMORY) &&
|
| - !(sqlite3OsDeviceCharacteristics(pPager->fd)&SQLITE_IOCAP_SAFE_APPEND)
|
| - ){
|
| - pPager->nRec = 0;
|
| - rc = writeJournalHdr(pPager);
|
| - }
|
| - }
|
| -
|
| - /* If the page number of this page is larger than the current size of
|
| - ** the database image, it may need to be written to the sub-journal.
|
| - ** This is because the call to pager_write_pagelist() below will not
|
| - ** actually write data to the file in this case.
|
| - **
|
| - ** Consider the following sequence of events:
|
| - **
|
| - ** BEGIN;
|
| - ** <journal page X>
|
| - ** <modify page X>
|
| - ** SAVEPOINT sp;
|
| - ** <shrink database file to Y pages>
|
| - ** pagerStress(page X)
|
| - ** ROLLBACK TO sp;
|
| - **
|
| - ** If (X>Y), then when pagerStress is called page X will not be written
|
| - ** out to the database file, but will be dropped from the cache. Then,
|
| - ** following the "ROLLBACK TO sp" statement, reading page X will read
|
| - ** data from the database file. This will be the copy of page X as it
|
| - ** was when the transaction started, not as it was when "SAVEPOINT sp"
|
| - ** was executed.
|
| - **
|
| - ** The solution is to write the current data for page X into the
|
| - ** sub-journal file now (if it is not already there), so that it will
|
| - ** be restored to its current value when the "ROLLBACK TO sp" is
|
| - ** executed.
|
| - */
|
| - if( NEVER(
|
| - rc==SQLITE_OK && pPg->pgno>pPager->dbSize && subjRequiresPage(pPg)
|
| - ) ){
|
| - rc = subjournalPage(pPg);
|
| - }
|
| -
|
| - /* Write the contents of the page out to the database file. */
|
| - if( rc==SQLITE_OK ){
|
| - pPg->pDirty = 0;
|
| - rc = pager_write_pagelist(pPg);
|
| - }
|
| -
|
| - /* Mark the page as clean. */
|
| - if( rc==SQLITE_OK ){
|
| - PAGERTRACE(("STRESS %d page %d\n", PAGERID(pPager), pPg->pgno));
|
| - sqlite3PcacheMakeClean(pPg);
|
| - }
|
| -
|
| - return pager_error(pPager, rc);
|
| -}
|
| -
|
| -
|
| -/*
|
| -** Allocate and initialize a new Pager object and put a pointer to it
|
| -** in *ppPager. The pager should eventually be freed by passing it
|
| -** to sqlite3PagerClose().
|
| -**
|
| -** The zFilename argument is the path to the database file to open.
|
| -** If zFilename is NULL then a randomly-named temporary file is created
|
| -** and used as the file to be cached. Temporary files are be deleted
|
| -** automatically when they are closed. If zFilename is ":memory:" then
|
| -** all information is held in cache. It is never written to disk.
|
| -** This can be used to implement an in-memory database.
|
| -**
|
| -** The nExtra parameter specifies the number of bytes of space allocated
|
| -** along with each page reference. This space is available to the user
|
| -** via the sqlite3PagerGetExtra() API.
|
| -**
|
| -** The flags argument is used to specify properties that affect the
|
| -** operation of the pager. It should be passed some bitwise combination
|
| -** of the PAGER_OMIT_JOURNAL and PAGER_NO_READLOCK flags.
|
| -**
|
| -** The vfsFlags parameter is a bitmask to pass to the flags parameter
|
| -** of the xOpen() method of the supplied VFS when opening files.
|
| -**
|
| -** If the pager object is allocated and the specified file opened
|
| -** successfully, SQLITE_OK is returned and *ppPager set to point to
|
| -** the new pager object. If an error occurs, *ppPager is set to NULL
|
| -** and error code returned. This function may return SQLITE_NOMEM
|
| -** (sqlite3Malloc() is used to allocate memory), SQLITE_CANTOPEN or
|
| -** various SQLITE_IO_XXX errors.
|
| -*/
|
| -int sqlite3PagerOpen(
|
| - sqlite3_vfs *pVfs, /* The virtual file system to use */
|
| - Pager **ppPager, /* OUT: Return the Pager structure here */
|
| - const char *zFilename, /* Name of the database file to open */
|
| - int nExtra, /* Extra bytes append to each in-memory page */
|
| - int flags, /* flags controlling this file */
|
| - int vfsFlags, /* flags passed through to sqlite3_vfs.xOpen() */
|
| - void (*xReinit)(DbPage*) /* Function to reinitialize pages */
|
| -){
|
| - u8 *pPtr;
|
| - Pager *pPager = 0; /* Pager object to allocate and return */
|
| - int rc = SQLITE_OK; /* Return code */
|
| - int tempFile = 0; /* True for temp files (incl. in-memory files) */
|
| - int memDb = 0; /* True if this is an in-memory file */
|
| - int readOnly = 0; /* True if this is a read-only file */
|
| - int journalFileSize; /* Bytes to allocate for each journal fd */
|
| - char *zPathname = 0; /* Full path to database file */
|
| - int nPathname = 0; /* Number of bytes in zPathname */
|
| - int useJournal = (flags & PAGER_OMIT_JOURNAL)==0; /* False to omit journal */
|
| - int noReadlock = (flags & PAGER_NO_READLOCK)!=0; /* True to omit read-lock */
|
| - int pcacheSize = sqlite3PcacheSize(); /* Bytes to allocate for PCache */
|
| - u16 szPageDflt = SQLITE_DEFAULT_PAGE_SIZE; /* Default page size */
|
| -
|
| - /* Figure out how much space is required for each journal file-handle
|
| - ** (there are two of them, the main journal and the sub-journal). This
|
| - ** is the maximum space required for an in-memory journal file handle
|
| - ** and a regular journal file-handle. Note that a "regular journal-handle"
|
| - ** may be a wrapper capable of caching the first portion of the journal
|
| - ** file in memory to implement the atomic-write optimization (see
|
| - ** source file journal.c).
|
| - */
|
| - if( sqlite3JournalSize(pVfs)>sqlite3MemJournalSize() ){
|
| - journalFileSize = ROUND8(sqlite3JournalSize(pVfs));
|
| - }else{
|
| - journalFileSize = ROUND8(sqlite3MemJournalSize());
|
| - }
|
| -
|
| - /* Set the output variable to NULL in case an error occurs. */
|
| - *ppPager = 0;
|
| -
|
| - /* Compute and store the full pathname in an allocated buffer pointed
|
| - ** to by zPathname, length nPathname. Or, if this is a temporary file,
|
| - ** leave both nPathname and zPathname set to 0.
|
| - */
|
| - if( zFilename && zFilename[0] ){
|
| - nPathname = pVfs->mxPathname+1;
|
| - zPathname = sqlite3Malloc(nPathname*2);
|
| - if( zPathname==0 ){
|
| - return SQLITE_NOMEM;
|
| - }
|
| -#ifndef SQLITE_OMIT_MEMORYDB
|
| - if( strcmp(zFilename,":memory:")==0 ){
|
| - memDb = 1;
|
| - zPathname[0] = 0;
|
| - }else
|
| -#endif
|
| - {
|
| - zPathname[0] = 0; /* Make sure initialized even if FullPathname() fails */
|
| - rc = sqlite3OsFullPathname(pVfs, zFilename, nPathname, zPathname);
|
| - }
|
| -
|
| - nPathname = sqlite3Strlen30(zPathname);
|
| - if( rc==SQLITE_OK && nPathname+8>pVfs->mxPathname ){
|
| - /* This branch is taken when the journal path required by
|
| - ** the database being opened will be more than pVfs->mxPathname
|
| - ** bytes in length. This means the database cannot be opened,
|
| - ** as it will not be possible to open the journal file or even
|
| - ** check for a hot-journal before reading.
|
| - */
|
| - rc = SQLITE_CANTOPEN;
|
| - }
|
| - if( rc!=SQLITE_OK ){
|
| - sqlite3_free(zPathname);
|
| - return rc;
|
| - }
|
| - }
|
| -
|
| - /* Allocate memory for the Pager structure, PCache object, the
|
| - ** three file descriptors, the database file name and the journal
|
| - ** file name. The layout in memory is as follows:
|
| - **
|
| - ** Pager object (sizeof(Pager) bytes)
|
| - ** PCache object (sqlite3PcacheSize() bytes)
|
| - ** Database file handle (pVfs->szOsFile bytes)
|
| - ** Sub-journal file handle (journalFileSize bytes)
|
| - ** Main journal file handle (journalFileSize bytes)
|
| - ** Database file name (nPathname+1 bytes)
|
| - ** Journal file name (nPathname+8+1 bytes)
|
| - */
|
| - pPtr = (u8 *)sqlite3MallocZero(
|
| - ROUND8(sizeof(*pPager)) + /* Pager structure */
|
| - ROUND8(pcacheSize) + /* PCache object */
|
| - ROUND8(pVfs->szOsFile) + /* The main db file */
|
| - journalFileSize * 2 + /* The two journal files */
|
| - nPathname + 1 + /* zFilename */
|
| - nPathname + 8 + 1 /* zJournal */
|
| - );
|
| - assert( EIGHT_BYTE_ALIGNMENT(SQLITE_INT_TO_PTR(journalFileSize)) );
|
| - if( !pPtr ){
|
| - sqlite3_free(zPathname);
|
| - return SQLITE_NOMEM;
|
| - }
|
| - pPager = (Pager*)(pPtr);
|
| - pPager->pPCache = (PCache*)(pPtr += ROUND8(sizeof(*pPager)));
|
| - pPager->fd = (sqlite3_file*)(pPtr += ROUND8(pcacheSize));
|
| - pPager->sjfd = (sqlite3_file*)(pPtr += ROUND8(pVfs->szOsFile));
|
| - pPager->jfd = (sqlite3_file*)(pPtr += journalFileSize);
|
| - pPager->zFilename = (char*)(pPtr += journalFileSize);
|
| - assert( EIGHT_BYTE_ALIGNMENT(pPager->jfd) );
|
| -
|
| - /* Fill in the Pager.zFilename and Pager.zJournal buffers, if required. */
|
| - if( zPathname ){
|
| - pPager->zJournal = (char*)(pPtr += nPathname + 1);
|
| - memcpy(pPager->zFilename, zPathname, nPathname);
|
| - memcpy(pPager->zJournal, zPathname, nPathname);
|
| - memcpy(&pPager->zJournal[nPathname], "-journal", 8);
|
| - if( pPager->zFilename[0]==0 ) pPager->zJournal[0] = 0;
|
| - sqlite3_free(zPathname);
|
| - }
|
| - pPager->pVfs = pVfs;
|
| - pPager->vfsFlags = vfsFlags;
|
| -
|
| - /* Open the pager file.
|
| - */
|
| - if( zFilename && zFilename[0] && !memDb ){
|
| - int fout = 0; /* VFS flags returned by xOpen() */
|
| - rc = sqlite3OsOpen(pVfs, pPager->zFilename, pPager->fd, vfsFlags, &fout);
|
| - readOnly = (fout&SQLITE_OPEN_READONLY);
|
| -
|
| - /* If the file was successfully opened for read/write access,
|
| - ** choose a default page size in case we have to create the
|
| - ** database file. The default page size is the maximum of:
|
| - **
|
| - ** + SQLITE_DEFAULT_PAGE_SIZE,
|
| - ** + The value returned by sqlite3OsSectorSize()
|
| - ** + The largest page size that can be written atomically.
|
| - */
|
| - if( rc==SQLITE_OK && !readOnly ){
|
| - setSectorSize(pPager);
|
| - assert(SQLITE_DEFAULT_PAGE_SIZE<=SQLITE_MAX_DEFAULT_PAGE_SIZE);
|
| - if( szPageDflt<pPager->sectorSize ){
|
| - if( pPager->sectorSize>SQLITE_MAX_DEFAULT_PAGE_SIZE ){
|
| - szPageDflt = SQLITE_MAX_DEFAULT_PAGE_SIZE;
|
| - }else{
|
| - szPageDflt = (u16)pPager->sectorSize;
|
| - }
|
| - }
|
| -#ifdef SQLITE_ENABLE_ATOMIC_WRITE
|
| - {
|
| - int iDc = sqlite3OsDeviceCharacteristics(pPager->fd);
|
| - int ii;
|
| - assert(SQLITE_IOCAP_ATOMIC512==(512>>8));
|
| - assert(SQLITE_IOCAP_ATOMIC64K==(65536>>8));
|
| - assert(SQLITE_MAX_DEFAULT_PAGE_SIZE<=65536);
|
| - for(ii=szPageDflt; ii<=SQLITE_MAX_DEFAULT_PAGE_SIZE; ii=ii*2){
|
| - if( iDc&(SQLITE_IOCAP_ATOMIC|(ii>>8)) ){
|
| - szPageDflt = ii;
|
| - }
|
| - }
|
| - }
|
| -#endif
|
| - }
|
| - }else{
|
| - /* If a temporary file is requested, it is not opened immediately.
|
| - ** In this case we accept the default page size and delay actually
|
| - ** opening the file until the first call to OsWrite().
|
| - **
|
| - ** This branch is also run for an in-memory database. An in-memory
|
| - ** database is the same as a temp-file that is never written out to
|
| - ** disk and uses an in-memory rollback journal.
|
| - */
|
| - tempFile = 1;
|
| - pPager->state = PAGER_EXCLUSIVE;
|
| - readOnly = (vfsFlags&SQLITE_OPEN_READONLY);
|
| - }
|
| -
|
| - /* The following call to PagerSetPagesize() serves to set the value of
|
| - ** Pager.pageSize and to allocate the Pager.pTmpSpace buffer.
|
| - */
|
| - if( rc==SQLITE_OK ){
|
| - assert( pPager->memDb==0 );
|
| - rc = sqlite3PagerSetPagesize(pPager, &szPageDflt, -1);
|
| - testcase( rc!=SQLITE_OK );
|
| - }
|
| -
|
| - /* If an error occurred in either of the blocks above, free the
|
| - ** Pager structure and close the file.
|
| - */
|
| - if( rc!=SQLITE_OK ){
|
| - assert( !pPager->pTmpSpace );
|
| - sqlite3OsClose(pPager->fd);
|
| - sqlite3_free(pPager);
|
| - return rc;
|
| - }
|
| -
|
| - /* Initialize the PCache object. */
|
| - assert( nExtra<1000 );
|
| - nExtra = ROUND8(nExtra);
|
| - sqlite3PcacheOpen(szPageDflt, nExtra, !memDb,
|
| - !memDb?pagerStress:0, (void *)pPager, pPager->pPCache);
|
| -
|
| - PAGERTRACE(("OPEN %d %s\n", FILEHANDLEID(pPager->fd), pPager->zFilename));
|
| - IOTRACE(("OPEN %p %s\n", pPager, pPager->zFilename))
|
| -
|
| - pPager->useJournal = (u8)useJournal;
|
| - pPager->noReadlock = (noReadlock && readOnly) ?1:0;
|
| - /* pPager->stmtOpen = 0; */
|
| - /* pPager->stmtInUse = 0; */
|
| - /* pPager->nRef = 0; */
|
| - pPager->dbSizeValid = (u8)memDb;
|
| - /* pPager->stmtSize = 0; */
|
| - /* pPager->stmtJSize = 0; */
|
| - /* pPager->nPage = 0; */
|
| - pPager->mxPgno = SQLITE_MAX_PAGE_COUNT;
|
| - /* pPager->state = PAGER_UNLOCK; */
|
| - assert( pPager->state == (tempFile ? PAGER_EXCLUSIVE : PAGER_UNLOCK) );
|
| - /* pPager->errMask = 0; */
|
| - pPager->tempFile = (u8)tempFile;
|
| - assert( tempFile==PAGER_LOCKINGMODE_NORMAL
|
| - || tempFile==PAGER_LOCKINGMODE_EXCLUSIVE );
|
| - assert( PAGER_LOCKINGMODE_EXCLUSIVE==1 );
|
| - pPager->exclusiveMode = (u8)tempFile;
|
| - pPager->changeCountDone = pPager->tempFile;
|
| - pPager->memDb = (u8)memDb;
|
| - pPager->readOnly = (u8)readOnly;
|
| - /* pPager->needSync = 0; */
|
| - assert( useJournal || pPager->tempFile );
|
| - pPager->noSync = pPager->tempFile;
|
| - pPager->fullSync = pPager->noSync ?0:1;
|
| - pPager->sync_flags = SQLITE_SYNC_NORMAL;
|
| - /* pPager->pFirst = 0; */
|
| - /* pPager->pFirstSynced = 0; */
|
| - /* pPager->pLast = 0; */
|
| - pPager->nExtra = (u16)nExtra;
|
| - pPager->journalSizeLimit = SQLITE_DEFAULT_JOURNAL_SIZE_LIMIT;
|
| - assert( isOpen(pPager->fd) || tempFile );
|
| - setSectorSize(pPager);
|
| - if( !useJournal ){
|
| - pPager->journalMode = PAGER_JOURNALMODE_OFF;
|
| - }else if( memDb ){
|
| - pPager->journalMode = PAGER_JOURNALMODE_MEMORY;
|
| - }
|
| - /* pPager->xBusyHandler = 0; */
|
| - /* pPager->pBusyHandlerArg = 0; */
|
| - pPager->xReiniter = xReinit;
|
| - /* memset(pPager->aHash, 0, sizeof(pPager->aHash)); */
|
| - *ppPager = pPager;
|
| - return SQLITE_OK;
|
| -}
|
| -
|
| -
|
| -
|
| -/*
|
| -** This function is called after transitioning from PAGER_UNLOCK to
|
| -** PAGER_SHARED state. It tests if there is a hot journal present in
|
| -** the file-system for the given pager. A hot journal is one that
|
| -** needs to be played back. According to this function, a hot-journal
|
| -** file exists if the following criteria are met:
|
| -**
|
| -** * The journal file exists in the file system, and
|
| -** * No process holds a RESERVED or greater lock on the database file, and
|
| -** * The database file itself is greater than 0 bytes in size, and
|
| -** * The first byte of the journal file exists and is not 0x00.
|
| -**
|
| -** If the current size of the database file is 0 but a journal file
|
| -** exists, that is probably an old journal left over from a prior
|
| -** database with the same name. In this case the journal file is
|
| -** just deleted using OsDelete, *pExists is set to 0 and SQLITE_OK
|
| -** is returned.
|
| -**
|
| -** This routine does not check if there is a master journal filename
|
| -** at the end of the file. If there is, and that master journal file
|
| -** does not exist, then the journal file is not really hot. In this
|
| -** case this routine will return a false-positive. The pager_playback()
|
| -** routine will discover that the journal file is not really hot and
|
| -** will not roll it back.
|
| -**
|
| -** If a hot-journal file is found to exist, *pExists is set to 1 and
|
| -** SQLITE_OK returned. If no hot-journal file is present, *pExists is
|
| -** set to 0 and SQLITE_OK returned. If an IO error occurs while trying
|
| -** to determine whether or not a hot-journal file exists, the IO error
|
| -** code is returned and the value of *pExists is undefined.
|
| -*/
|
| -static int hasHotJournal(Pager *pPager, int *pExists){
|
| - sqlite3_vfs * const pVfs = pPager->pVfs;
|
| - int rc; /* Return code */
|
| - int exists; /* True if a journal file is present */
|
| -
|
| - assert( pPager!=0 );
|
| - assert( pPager->useJournal );
|
| - assert( isOpen(pPager->fd) );
|
| - assert( !isOpen(pPager->jfd) );
|
| - assert( pPager->state <= PAGER_SHARED );
|
| -
|
| - *pExists = 0;
|
| - rc = sqlite3OsAccess(pVfs, pPager->zJournal, SQLITE_ACCESS_EXISTS, &exists);
|
| - if( rc==SQLITE_OK && exists ){
|
| - int locked; /* True if some process holds a RESERVED lock */
|
| -
|
| - /* Race condition here: Another process might have been holding the
|
| - ** the RESERVED lock and have a journal open at the sqlite3OsAccess()
|
| - ** call above, but then delete the journal and drop the lock before
|
| - ** we get to the following sqlite3OsCheckReservedLock() call. If that
|
| - ** is the case, this routine might think there is a hot journal when
|
| - ** in fact there is none. This results in a false-positive which will
|
| - ** be dealt with by the playback routine. Ticket #3883.
|
| - */
|
| - rc = sqlite3OsCheckReservedLock(pPager->fd, &locked);
|
| - if( rc==SQLITE_OK && !locked ){
|
| - int nPage;
|
| -
|
| - /* Check the size of the database file. If it consists of 0 pages,
|
| - ** then delete the journal file. See the header comment above for
|
| - ** the reasoning here. Delete the obsolete journal file under
|
| - ** a RESERVED lock to avoid race conditions and to avoid violating
|
| - ** [H33020].
|
| - */
|
| - rc = sqlite3PagerPagecount(pPager, &nPage);
|
| - if( rc==SQLITE_OK ){
|
| - if( nPage==0 ){
|
| - sqlite3BeginBenignMalloc();
|
| - if( sqlite3OsLock(pPager->fd, RESERVED_LOCK)==SQLITE_OK ){
|
| - sqlite3OsDelete(pVfs, pPager->zJournal, 0);
|
| - sqlite3OsUnlock(pPager->fd, SHARED_LOCK);
|
| - }
|
| - sqlite3EndBenignMalloc();
|
| - }else{
|
| - /* The journal file exists and no other connection has a reserved
|
| - ** or greater lock on the database file. Now check that there is
|
| - ** at least one non-zero bytes at the start of the journal file.
|
| - ** If there is, then we consider this journal to be hot. If not,
|
| - ** it can be ignored.
|
| - */
|
| - int f = SQLITE_OPEN_READONLY|SQLITE_OPEN_MAIN_JOURNAL;
|
| - rc = sqlite3OsOpen(pVfs, pPager->zJournal, pPager->jfd, f, &f);
|
| - if( rc==SQLITE_OK ){
|
| - u8 first = 0;
|
| - rc = sqlite3OsRead(pPager->jfd, (void *)&first, 1, 0);
|
| - if( rc==SQLITE_IOERR_SHORT_READ ){
|
| - rc = SQLITE_OK;
|
| - }
|
| - sqlite3OsClose(pPager->jfd);
|
| - *pExists = (first!=0);
|
| - }else if( rc==SQLITE_CANTOPEN ){
|
| - /* If we cannot open the rollback journal file in order to see if
|
| - ** its has a zero header, that might be due to an I/O error, or
|
| - ** it might be due to the race condition described above and in
|
| - ** ticket #3883. Either way, assume that the journal is hot.
|
| - ** This might be a false positive. But if it is, then the
|
| - ** automatic journal playback and recovery mechanism will deal
|
| - ** with it under an EXCLUSIVE lock where we do not need to
|
| - ** worry so much with race conditions.
|
| - */
|
| - *pExists = 1;
|
| - rc = SQLITE_OK;
|
| - }
|
| - }
|
| - }
|
| - }
|
| - }
|
| -
|
| - return rc;
|
| -}
|
| -
|
| -/*
|
| -** Read the content for page pPg out of the database file and into
|
| -** pPg->pData. A shared lock or greater must be held on the database
|
| -** file before this function is called.
|
| -**
|
| -** If page 1 is read, then the value of Pager.dbFileVers[] is set to
|
| -** the value read from the database file.
|
| -**
|
| -** If an IO error occurs, then the IO error is returned to the caller.
|
| -** Otherwise, SQLITE_OK is returned.
|
| -*/
|
| -static int readDbPage(PgHdr *pPg){
|
| - Pager *pPager = pPg->pPager; /* Pager object associated with page pPg */
|
| - Pgno pgno = pPg->pgno; /* Page number to read */
|
| - int rc; /* Return code */
|
| - i64 iOffset; /* Byte offset of file to read from */
|
| -
|
| - assert( pPager->state>=PAGER_SHARED && !MEMDB );
|
| - assert( isOpen(pPager->fd) );
|
| -
|
| - if( NEVER(!isOpen(pPager->fd)) ){
|
| - assert( pPager->tempFile );
|
| - memset(pPg->pData, 0, pPager->pageSize);
|
| - return SQLITE_OK;
|
| - }
|
| - iOffset = (pgno-1)*(i64)pPager->pageSize;
|
| - rc = sqlite3OsRead(pPager->fd, pPg->pData, pPager->pageSize, iOffset);
|
| - if( rc==SQLITE_IOERR_SHORT_READ ){
|
| - rc = SQLITE_OK;
|
| - }
|
| - if( pgno==1 ){
|
| - u8 *dbFileVers = &((u8*)pPg->pData)[24];
|
| - memcpy(&pPager->dbFileVers, dbFileVers, sizeof(pPager->dbFileVers));
|
| - }
|
| - CODEC1(pPager, pPg->pData, pgno, 3, rc = SQLITE_NOMEM);
|
| -
|
| - PAGER_INCR(sqlite3_pager_readdb_count);
|
| - PAGER_INCR(pPager->nRead);
|
| - IOTRACE(("PGIN %p %d\n", pPager, pgno));
|
| - PAGERTRACE(("FETCH %d page %d hash(%08x)\n",
|
| - PAGERID(pPager), pgno, pager_pagehash(pPg)));
|
| -
|
| - return rc;
|
| -}
|
| -
|
| -/*
|
| -** This function is called to obtain a shared lock on the database file.
|
| -** It is illegal to call sqlite3PagerAcquire() until after this function
|
| -** has been successfully called. If a shared-lock is already held when
|
| -** this function is called, it is a no-op.
|
| -**
|
| -** The following operations are also performed by this function.
|
| -**
|
| -** 1) If the pager is currently in PAGER_UNLOCK state (no lock held
|
| -** on the database file), then an attempt is made to obtain a
|
| -** SHARED lock on the database file. Immediately after obtaining
|
| -** the SHARED lock, the file-system is checked for a hot-journal,
|
| -** which is played back if present. Following any hot-journal
|
| -** rollback, the contents of the cache are validated by checking
|
| -** the 'change-counter' field of the database file header and
|
| -** discarded if they are found to be invalid.
|
| -**
|
| -** 2) If the pager is running in exclusive-mode, and there are currently
|
| -** no outstanding references to any pages, and is in the error state,
|
| -** then an attempt is made to clear the error state by discarding
|
| -** the contents of the page cache and rolling back any open journal
|
| -** file.
|
| -**
|
| -** If the operation described by (2) above is not attempted, and if the
|
| -** pager is in an error state other than SQLITE_FULL when this is called,
|
| -** the error state error code is returned. It is permitted to read the
|
| -** database when in SQLITE_FULL error state.
|
| -**
|
| -** Otherwise, if everything is successful, SQLITE_OK is returned. If an
|
| -** IO error occurs while locking the database, checking for a hot-journal
|
| -** file or rolling back a journal file, the IO error code is returned.
|
| -*/
|
| -int sqlite3PagerSharedLock(Pager *pPager){
|
| - int rc = SQLITE_OK; /* Return code */
|
| - int isErrorReset = 0; /* True if recovering from error state */
|
| -
|
| - /* This routine is only called from b-tree and only when there are no
|
| - ** outstanding pages */
|
| - assert( sqlite3PcacheRefCount(pPager->pPCache)==0 );
|
| - if( NEVER(MEMDB && pPager->errCode) ){ return pPager->errCode; }
|
| -
|
| - /* If this database is in an error-state, now is a chance to clear
|
| - ** the error. Discard the contents of the pager-cache and rollback
|
| - ** any hot journal in the file-system.
|
| - */
|
| - if( pPager->errCode ){
|
| - if( isOpen(pPager->jfd) || pPager->zJournal ){
|
| - isErrorReset = 1;
|
| - }
|
| - pPager->errCode = SQLITE_OK;
|
| - pager_reset(pPager);
|
| - }
|
| -
|
| - if( pPager->state==PAGER_UNLOCK || isErrorReset ){
|
| - sqlite3_vfs * const pVfs = pPager->pVfs;
|
| - int isHotJournal = 0;
|
| - assert( !MEMDB );
|
| - assert( sqlite3PcacheRefCount(pPager->pPCache)==0 );
|
| - if( pPager->noReadlock ){
|
| - assert( pPager->readOnly );
|
| - pPager->state = PAGER_SHARED;
|
| - }else{
|
| - rc = pager_wait_on_lock(pPager, SHARED_LOCK);
|
| - if( rc!=SQLITE_OK ){
|
| - assert( pPager->state==PAGER_UNLOCK );
|
| - return pager_error(pPager, rc);
|
| - }
|
| - }
|
| - assert( pPager->state>=SHARED_LOCK );
|
| -
|
| - /* If a journal file exists, and there is no RESERVED lock on the
|
| - ** database file, then it either needs to be played back or deleted.
|
| - */
|
| - if( !isErrorReset ){
|
| - assert( pPager->state <= PAGER_SHARED );
|
| - rc = hasHotJournal(pPager, &isHotJournal);
|
| - if( rc!=SQLITE_OK ){
|
| - goto failed;
|
| - }
|
| - }
|
| - if( isErrorReset || isHotJournal ){
|
| - /* Get an EXCLUSIVE lock on the database file. At this point it is
|
| - ** important that a RESERVED lock is not obtained on the way to the
|
| - ** EXCLUSIVE lock. If it were, another process might open the
|
| - ** database file, detect the RESERVED lock, and conclude that the
|
| - ** database is safe to read while this process is still rolling the
|
| - ** hot-journal back.
|
| - **
|
| - ** Because the intermediate RESERVED lock is not requested, any
|
| - ** other process attempting to access the database file will get to
|
| - ** this point in the code and fail to obtain its own EXCLUSIVE lock
|
| - ** on the database file.
|
| - */
|
| - if( pPager->state<EXCLUSIVE_LOCK ){
|
| - rc = sqlite3OsLock(pPager->fd, EXCLUSIVE_LOCK);
|
| - if( rc!=SQLITE_OK ){
|
| - rc = pager_error(pPager, rc);
|
| - goto failed;
|
| - }
|
| - pPager->state = PAGER_EXCLUSIVE;
|
| - }
|
| -
|
| - /* Open the journal for read/write access. This is because in
|
| - ** exclusive-access mode the file descriptor will be kept open and
|
| - ** possibly used for a transaction later on. On some systems, the
|
| - ** OsTruncate() call used in exclusive-access mode also requires
|
| - ** a read/write file handle.
|
| - */
|
| - if( !isOpen(pPager->jfd) ){
|
| - int res;
|
| - rc = sqlite3OsAccess(pVfs,pPager->zJournal,SQLITE_ACCESS_EXISTS,&res);
|
| - if( rc==SQLITE_OK ){
|
| - if( res ){
|
| - int fout = 0;
|
| - int f = SQLITE_OPEN_READWRITE|SQLITE_OPEN_MAIN_JOURNAL;
|
| - assert( !pPager->tempFile );
|
| - rc = sqlite3OsOpen(pVfs, pPager->zJournal, pPager->jfd, f, &fout);
|
| - assert( rc!=SQLITE_OK || isOpen(pPager->jfd) );
|
| - if( rc==SQLITE_OK && fout&SQLITE_OPEN_READONLY ){
|
| - rc = SQLITE_CANTOPEN;
|
| - sqlite3OsClose(pPager->jfd);
|
| - }
|
| - }else{
|
| - /* If the journal does not exist, it usually means that some
|
| - ** other connection managed to get in and roll it back before
|
| - ** this connection obtained the exclusive lock above. Or, it
|
| - ** may mean that the pager was in the error-state when this
|
| - ** function was called and the journal file does not exist. */
|
| - rc = pager_end_transaction(pPager, 0);
|
| - }
|
| - }
|
| - }
|
| - if( rc!=SQLITE_OK ){
|
| - goto failed;
|
| - }
|
| -
|
| - /* TODO: Why are these cleared here? Is it necessary? */
|
| - pPager->journalStarted = 0;
|
| - pPager->journalOff = 0;
|
| - pPager->setMaster = 0;
|
| - pPager->journalHdr = 0;
|
| -
|
| - /* Playback and delete the journal. Drop the database write
|
| - ** lock and reacquire the read lock. Purge the cache before
|
| - ** playing back the hot-journal so that we don't end up with
|
| - ** an inconsistent cache.
|
| - */
|
| - if( isOpen(pPager->jfd) ){
|
| - rc = pager_playback(pPager, 1);
|
| - if( rc!=SQLITE_OK ){
|
| - rc = pager_error(pPager, rc);
|
| - goto failed;
|
| - }
|
| - }
|
| - assert( (pPager->state==PAGER_SHARED)
|
| - || (pPager->exclusiveMode && pPager->state>PAGER_SHARED)
|
| - );
|
| - }
|
| -
|
| - if( pPager->pBackup || sqlite3PcachePagecount(pPager->pPCache)>0 ){
|
| - /* The shared-lock has just been acquired on the database file
|
| - ** and there are already pages in the cache (from a previous
|
| - ** read or write transaction). Check to see if the database
|
| - ** has been modified. If the database has changed, flush the
|
| - ** cache.
|
| - **
|
| - ** Database changes is detected by looking at 15 bytes beginning
|
| - ** at offset 24 into the file. The first 4 of these 16 bytes are
|
| - ** a 32-bit counter that is incremented with each change. The
|
| - ** other bytes change randomly with each file change when
|
| - ** a codec is in use.
|
| - **
|
| - ** There is a vanishingly small chance that a change will not be
|
| - ** detected. The chance of an undetected change is so small that
|
| - ** it can be neglected.
|
| - */
|
| - char dbFileVers[sizeof(pPager->dbFileVers)];
|
| - sqlite3PagerPagecount(pPager, 0);
|
| -
|
| - if( pPager->errCode ){
|
| - rc = pPager->errCode;
|
| - goto failed;
|
| - }
|
| -
|
| - assert( pPager->dbSizeValid );
|
| - if( pPager->dbSize>0 ){
|
| - IOTRACE(("CKVERS %p %d\n", pPager, sizeof(dbFileVers)));
|
| - rc = sqlite3OsRead(pPager->fd, &dbFileVers, sizeof(dbFileVers), 24);
|
| - if( rc!=SQLITE_OK ){
|
| - goto failed;
|
| - }
|
| - }else{
|
| - memset(dbFileVers, 0, sizeof(dbFileVers));
|
| - }
|
| -
|
| - if( memcmp(pPager->dbFileVers, dbFileVers, sizeof(dbFileVers))!=0 ){
|
| - pager_reset(pPager);
|
| - }
|
| - }
|
| - assert( pPager->exclusiveMode || pPager->state==PAGER_SHARED );
|
| - }
|
| -
|
| - failed:
|
| - if( rc!=SQLITE_OK ){
|
| - /* pager_unlock() is a no-op for exclusive mode and in-memory databases. */
|
| - pager_unlock(pPager);
|
| - }
|
| - return rc;
|
| -}
|
| -
|
| -/*
|
| -** If the reference count has reached zero, rollback any active
|
| -** transaction and unlock the pager.
|
| -**
|
| -** Except, in locking_mode=EXCLUSIVE when there is nothing to in
|
| -** the rollback journal, the unlock is not performed and there is
|
| -** nothing to rollback, so this routine is a no-op.
|
| -*/
|
| -static void pagerUnlockIfUnused(Pager *pPager){
|
| - if( (sqlite3PcacheRefCount(pPager->pPCache)==0)
|
| - && (!pPager->exclusiveMode || pPager->journalOff>0)
|
| - ){
|
| - pagerUnlockAndRollback(pPager);
|
| - }
|
| -}
|
| -
|
| -/*
|
| -** Acquire a reference to page number pgno in pager pPager (a page
|
| -** reference has type DbPage*). If the requested reference is
|
| -** successfully obtained, it is copied to *ppPage and SQLITE_OK returned.
|
| -**
|
| -** If the requested page is already in the cache, it is returned.
|
| -** Otherwise, a new page object is allocated and populated with data
|
| -** read from the database file. In some cases, the pcache module may
|
| -** choose not to allocate a new page object and may reuse an existing
|
| -** object with no outstanding references.
|
| -**
|
| -** The extra data appended to a page is always initialized to zeros the
|
| -** first time a page is loaded into memory. If the page requested is
|
| -** already in the cache when this function is called, then the extra
|
| -** data is left as it was when the page object was last used.
|
| -**
|
| -** If the database image is smaller than the requested page or if a
|
| -** non-zero value is passed as the noContent parameter and the
|
| -** requested page is not already stored in the cache, then no
|
| -** actual disk read occurs. In this case the memory image of the
|
| -** page is initialized to all zeros.
|
| -**
|
| -** If noContent is true, it means that we do not care about the contents
|
| -** of the page. This occurs in two seperate scenarios:
|
| -**
|
| -** a) When reading a free-list leaf page from the database, and
|
| -**
|
| -** b) When a savepoint is being rolled back and we need to load
|
| -** a new page into the cache to populate with the data read
|
| -** from the savepoint journal.
|
| -**
|
| -** If noContent is true, then the data returned is zeroed instead of
|
| -** being read from the database. Additionally, the bits corresponding
|
| -** to pgno in Pager.pInJournal (bitvec of pages already written to the
|
| -** journal file) and the PagerSavepoint.pInSavepoint bitvecs of any open
|
| -** savepoints are set. This means if the page is made writable at any
|
| -** point in the future, using a call to sqlite3PagerWrite(), its contents
|
| -** will not be journaled. This saves IO.
|
| -**
|
| -** The acquisition might fail for several reasons. In all cases,
|
| -** an appropriate error code is returned and *ppPage is set to NULL.
|
| -**
|
| -** See also sqlite3PagerLookup(). Both this routine and Lookup() attempt
|
| -** to find a page in the in-memory cache first. If the page is not already
|
| -** in memory, this routine goes to disk to read it in whereas Lookup()
|
| -** just returns 0. This routine acquires a read-lock the first time it
|
| -** has to go to disk, and could also playback an old journal if necessary.
|
| -** Since Lookup() never goes to disk, it never has to deal with locks
|
| -** or journal files.
|
| -*/
|
| -int sqlite3PagerAcquire(
|
| - Pager *pPager, /* The pager open on the database file */
|
| - Pgno pgno, /* Page number to fetch */
|
| - DbPage **ppPage, /* Write a pointer to the page here */
|
| - int noContent /* Do not bother reading content from disk if true */
|
| -){
|
| - /* This just passes through to our modified version with NULL data. */
|
| - return sqlite3PagerAcquire2(pPager, pgno, ppPage, noContent, 0);
|
| -}
|
| -
|
| -/*
|
| -** This is an internal version of sqlite3PagerAcquire that takes an extra
|
| -** parameter of data to use to fill the page with. This allows more efficient
|
| -** filling for preloaded data. If this extra parameter is NULL, we'll go to
|
| -** the file.
|
| -**
|
| -** See sqlite3PagerLoadall which uses this function.
|
| -*/
|
| -int sqlite3PagerAcquire2(
|
| - Pager *pPager, /* The pager open on the database file */
|
| - Pgno pgno, /* Page number to fetch */
|
| - DbPage **ppPage, /* Write a pointer to the page here */
|
| - int noContent, /* Do not bother reading content from disk if true */
|
| - unsigned char* pDataToFill
|
| -){
|
| - int rc;
|
| - PgHdr *pPg;
|
| -
|
| - assert( assert_pager_state(pPager) );
|
| - assert( pPager->state>PAGER_UNLOCK );
|
| -
|
| - if( pgno==0 ){
|
| - return SQLITE_CORRUPT_BKPT;
|
| - }
|
| -
|
| - /* If the pager is in the error state, return an error immediately.
|
| - ** Otherwise, request the page from the PCache layer. */
|
| - if( pPager->errCode!=SQLITE_OK && pPager->errCode!=SQLITE_FULL ){
|
| - rc = pPager->errCode;
|
| - }else{
|
| - rc = sqlite3PcacheFetch(pPager->pPCache, pgno, 1, ppPage);
|
| - }
|
| -
|
| - if( rc!=SQLITE_OK ){
|
| - /* Either the call to sqlite3PcacheFetch() returned an error or the
|
| - ** pager was already in the error-state when this function was called.
|
| - ** Set pPg to 0 and jump to the exception handler. */
|
| - pPg = 0;
|
| - goto pager_acquire_err;
|
| - }
|
| - assert( (*ppPage)->pgno==pgno );
|
| - assert( (*ppPage)->pPager==pPager || (*ppPage)->pPager==0 );
|
| -
|
| - if( (*ppPage)->pPager ){
|
| - /* In this case the pcache already contains an initialized copy of
|
| - ** the page. Return without further ado. */
|
| - assert( pgno<=PAGER_MAX_PGNO && pgno!=PAGER_MJ_PGNO(pPager) );
|
| - PAGER_INCR(pPager->nHit);
|
| - return SQLITE_OK;
|
| -
|
| - }else{
|
| - /* The pager cache has created a new page. Its content needs to
|
| - ** be initialized. */
|
| - int nMax;
|
| -
|
| - PAGER_INCR(pPager->nMiss);
|
| - pPg = *ppPage;
|
| - pPg->pPager = pPager;
|
| -
|
| - /* The maximum page number is 2^31. Return SQLITE_CORRUPT if a page
|
| - ** number greater than this, or the unused locking-page, is requested. */
|
| - if( pgno>PAGER_MAX_PGNO || pgno==PAGER_MJ_PGNO(pPager) ){
|
| - rc = SQLITE_CORRUPT_BKPT;
|
| - goto pager_acquire_err;
|
| - }
|
| -
|
| - rc = sqlite3PagerPagecount(pPager, &nMax);
|
| - if( rc!=SQLITE_OK ){
|
| - goto pager_acquire_err;
|
| - }
|
| -
|
| - if( nMax<(int)pgno || MEMDB || noContent ){
|
| - if( pgno>pPager->mxPgno ){
|
| - rc = SQLITE_FULL;
|
| - goto pager_acquire_err;
|
| - }
|
| - if( noContent ){
|
| - /* Failure to set the bits in the InJournal bit-vectors is benign.
|
| - ** It merely means that we might do some extra work to journal a
|
| - ** page that does not need to be journaled. Nevertheless, be sure
|
| - ** to test the case where a malloc error occurs while trying to set
|
| - ** a bit in a bit vector.
|
| - */
|
| - sqlite3BeginBenignMalloc();
|
| - if( pgno<=pPager->dbOrigSize ){
|
| - TESTONLY( rc = ) sqlite3BitvecSet(pPager->pInJournal, pgno);
|
| - testcase( rc==SQLITE_NOMEM );
|
| - }
|
| - TESTONLY( rc = ) addToSavepointBitvecs(pPager, pgno);
|
| - testcase( rc==SQLITE_NOMEM );
|
| - sqlite3EndBenignMalloc();
|
| - }else{
|
| - memset(pPg->pData, 0, pPager->pageSize);
|
| - }
|
| - IOTRACE(("ZERO %p %d\n", pPager, pgno));
|
| - }else{
|
| - assert( pPg->pPager==pPager );
|
| - if( pDataToFill ){
|
| - /* Just copy from the given memory */
|
| - memcpy(pPg->pData, pDataToFill, pPager->pageSize);
|
| - CODEC1(pPager, pPg->pData, pPg->pgno, 3, rc = SQLITE_NOMEM;
|
| - goto pager_acquire_err);
|
| - }else{
|
| - /* Load from disk (old regular sqlite code path) */
|
| - rc = readDbPage(pPg);
|
| - if( rc!=SQLITE_OK ){
|
| - goto pager_acquire_err;
|
| - }
|
| - }
|
| - }
|
| -#ifdef SQLITE_CHECK_PAGES
|
| - pPg->pageHash = pager_pagehash(pPg);
|
| -#endif
|
| - }
|
| -
|
| - return SQLITE_OK;
|
| -
|
| -pager_acquire_err:
|
| - assert( rc!=SQLITE_OK );
|
| - if( pPg ){
|
| - sqlite3PcacheDrop(pPg);
|
| - }
|
| - pagerUnlockIfUnused(pPager);
|
| -
|
| - *ppPage = 0;
|
| - return rc;
|
| -}
|
| -
|
| -/*
|
| -** Acquire a page if it is already in the in-memory cache. Do
|
| -** not read the page from disk. Return a pointer to the page,
|
| -** or 0 if the page is not in cache. Also, return 0 if the
|
| -** pager is in PAGER_UNLOCK state when this function is called,
|
| -** or if the pager is in an error state other than SQLITE_FULL.
|
| -**
|
| -** See also sqlite3PagerGet(). The difference between this routine
|
| -** and sqlite3PagerGet() is that _get() will go to the disk and read
|
| -** in the page if the page is not already in cache. This routine
|
| -** returns NULL if the page is not in cache or if a disk I/O error
|
| -** has ever happened.
|
| -*/
|
| -DbPage *sqlite3PagerLookup(Pager *pPager, Pgno pgno){
|
| - PgHdr *pPg = 0;
|
| - assert( pPager!=0 );
|
| - assert( pgno!=0 );
|
| - assert( pPager->pPCache!=0 );
|
| - assert( pPager->state > PAGER_UNLOCK );
|
| - sqlite3PcacheFetch(pPager->pPCache, pgno, 0, &pPg);
|
| - return pPg;
|
| -}
|
| -
|
| -/*
|
| -** Release a page reference.
|
| -**
|
| -** If the number of references to the page drop to zero, then the
|
| -** page is added to the LRU list. When all references to all pages
|
| -** are released, a rollback occurs and the lock on the database is
|
| -** removed.
|
| -*/
|
| -void sqlite3PagerUnref(DbPage *pPg){
|
| - if( pPg ){
|
| - Pager *pPager = pPg->pPager;
|
| - sqlite3PcacheRelease(pPg);
|
| - pagerUnlockIfUnused(pPager);
|
| - }
|
| -}
|
| -
|
| -/*
|
| -** If the main journal file has already been opened, ensure that the
|
| -** sub-journal file is open too. If the main journal is not open,
|
| -** this function is a no-op.
|
| -**
|
| -** SQLITE_OK is returned if everything goes according to plan.
|
| -** An SQLITE_IOERR_XXX error code is returned if a call to
|
| -** sqlite3OsOpen() fails.
|
| -*/
|
| -static int openSubJournal(Pager *pPager){
|
| - int rc = SQLITE_OK;
|
| - if( isOpen(pPager->jfd) && !isOpen(pPager->sjfd) ){
|
| - if( pPager->journalMode==PAGER_JOURNALMODE_MEMORY || pPager->subjInMemory ){
|
| - sqlite3MemJournalOpen(pPager->sjfd);
|
| - }else{
|
| - rc = pagerOpentemp(pPager, pPager->sjfd, SQLITE_OPEN_SUBJOURNAL);
|
| - }
|
| - }
|
| - return rc;
|
| -}
|
| -
|
| -/*
|
| -** This function is called at the start of every write transaction.
|
| -** There must already be a RESERVED or EXCLUSIVE lock on the database
|
| -** file when this routine is called.
|
| -**
|
| -** Open the journal file for pager pPager and write a journal header
|
| -** to the start of it. If there are active savepoints, open the sub-journal
|
| -** as well. This function is only used when the journal file is being
|
| -** opened to write a rollback log for a transaction. It is not used
|
| -** when opening a hot journal file to roll it back.
|
| -**
|
| -** If the journal file is already open (as it may be in exclusive mode),
|
| -** then this function just writes a journal header to the start of the
|
| -** already open file.
|
| -**
|
| -** Whether or not the journal file is opened by this function, the
|
| -** Pager.pInJournal bitvec structure is allocated.
|
| -**
|
| -** Return SQLITE_OK if everything is successful. Otherwise, return
|
| -** SQLITE_NOMEM if the attempt to allocate Pager.pInJournal fails, or
|
| -** an IO error code if opening or writing the journal file fails.
|
| -*/
|
| -static int pager_open_journal(Pager *pPager){
|
| - int rc = SQLITE_OK; /* Return code */
|
| - sqlite3_vfs * const pVfs = pPager->pVfs; /* Local cache of vfs pointer */
|
| -
|
| - assert( pPager->state>=PAGER_RESERVED );
|
| - assert( pPager->useJournal );
|
| - assert( pPager->journalMode!=PAGER_JOURNALMODE_OFF );
|
| - assert( pPager->pInJournal==0 );
|
| -
|
| - /* If already in the error state, this function is a no-op. But on
|
| - ** the other hand, this routine is never called if we are already in
|
| - ** an error state. */
|
| - if( NEVER(pPager->errCode) ) return pPager->errCode;
|
| -
|
| - /* TODO: Is it really possible to get here with dbSizeValid==0? If not,
|
| - ** the call to PagerPagecount() can be removed.
|
| - */
|
| - testcase( pPager->dbSizeValid==0 );
|
| - sqlite3PagerPagecount(pPager, 0);
|
| -
|
| - pPager->pInJournal = sqlite3BitvecCreate(pPager->dbSize);
|
| - if( pPager->pInJournal==0 ){
|
| - return SQLITE_NOMEM;
|
| - }
|
| -
|
| - /* Open the journal file if it is not already open. */
|
| - if( !isOpen(pPager->jfd) ){
|
| - if( pPager->journalMode==PAGER_JOURNALMODE_MEMORY ){
|
| - sqlite3MemJournalOpen(pPager->jfd);
|
| - }else{
|
| - const int flags = /* VFS flags to open journal file */
|
| - SQLITE_OPEN_READWRITE|SQLITE_OPEN_CREATE|
|
| - (pPager->tempFile ?
|
| - (SQLITE_OPEN_DELETEONCLOSE|SQLITE_OPEN_TEMP_JOURNAL):
|
| - (SQLITE_OPEN_MAIN_JOURNAL)
|
| - );
|
| -#ifdef SQLITE_ENABLE_ATOMIC_WRITE
|
| - rc = sqlite3JournalOpen(
|
| - pVfs, pPager->zJournal, pPager->jfd, flags, jrnlBufferSize(pPager)
|
| - );
|
| -#else
|
| - rc = sqlite3OsOpen(pVfs, pPager->zJournal, pPager->jfd, flags, 0);
|
| -#endif
|
| - }
|
| - assert( rc!=SQLITE_OK || isOpen(pPager->jfd) );
|
| - }
|
| -
|
| -
|
| - /* Write the first journal header to the journal file and open
|
| - ** the sub-journal if necessary.
|
| - */
|
| - if( rc==SQLITE_OK ){
|
| - /* TODO: Check if all of these are really required. */
|
| - pPager->dbOrigSize = pPager->dbSize;
|
| - pPager->journalStarted = 0;
|
| - pPager->needSync = 0;
|
| - pPager->nRec = 0;
|
| - pPager->journalOff = 0;
|
| - pPager->setMaster = 0;
|
| - pPager->journalHdr = 0;
|
| - rc = writeJournalHdr(pPager);
|
| - }
|
| - if( rc==SQLITE_OK && pPager->nSavepoint ){
|
| - rc = openSubJournal(pPager);
|
| - }
|
| -
|
| - if( rc!=SQLITE_OK ){
|
| - sqlite3BitvecDestroy(pPager->pInJournal);
|
| - pPager->pInJournal = 0;
|
| - }
|
| - return rc;
|
| -}
|
| -
|
| -/*
|
| -** Begin a write-transaction on the specified pager object. If a
|
| -** write-transaction has already been opened, this function is a no-op.
|
| -**
|
| -** If the exFlag argument is false, then acquire at least a RESERVED
|
| -** lock on the database file. If exFlag is true, then acquire at least
|
| -** an EXCLUSIVE lock. If such a lock is already held, no locking
|
| -** functions need be called.
|
| -**
|
| -** If this is not a temporary or in-memory file and, the journal file is
|
| -** opened if it has not been already. For a temporary file, the opening
|
| -** of the journal file is deferred until there is an actual need to
|
| -** write to the journal. TODO: Why handle temporary files differently?
|
| -**
|
| -** If the journal file is opened (or if it is already open), then a
|
| -** journal-header is written to the start of it.
|
| -**
|
| -** If the subjInMemory argument is non-zero, then any sub-journal opened
|
| -** within this transaction will be opened as an in-memory file. This
|
| -** has no effect if the sub-journal is already opened (as it may be when
|
| -** running in exclusive mode) or if the transaction does not require a
|
| -** sub-journal. If the subjInMemory argument is zero, then any required
|
| -** sub-journal is implemented in-memory if pPager is an in-memory database,
|
| -** or using a temporary file otherwise.
|
| -*/
|
| -int sqlite3PagerBegin(Pager *pPager, int exFlag, int subjInMemory){
|
| - int rc = SQLITE_OK;
|
| - assert( pPager->state!=PAGER_UNLOCK );
|
| - pPager->subjInMemory = (u8)subjInMemory;
|
| - if( pPager->state==PAGER_SHARED ){
|
| - assert( pPager->pInJournal==0 );
|
| - assert( !MEMDB && !pPager->tempFile );
|
| -
|
| - /* Obtain a RESERVED lock on the database file. If the exFlag parameter
|
| - ** is true, then immediately upgrade this to an EXCLUSIVE lock. The
|
| - ** busy-handler callback can be used when upgrading to the EXCLUSIVE
|
| - ** lock, but not when obtaining the RESERVED lock.
|
| - */
|
| - rc = sqlite3OsLock(pPager->fd, RESERVED_LOCK);
|
| - if( rc==SQLITE_OK ){
|
| - pPager->state = PAGER_RESERVED;
|
| - if( exFlag ){
|
| - rc = pager_wait_on_lock(pPager, EXCLUSIVE_LOCK);
|
| - }
|
| - }
|
| -
|
| - /* If the required locks were successfully obtained, open the journal
|
| - ** file and write the first journal-header to it.
|
| - */
|
| - if( rc==SQLITE_OK && pPager->journalMode!=PAGER_JOURNALMODE_OFF ){
|
| - rc = pager_open_journal(pPager);
|
| - }
|
| - }else if( isOpen(pPager->jfd) && pPager->journalOff==0 ){
|
| - /* This happens when the pager was in exclusive-access mode the last
|
| - ** time a (read or write) transaction was successfully concluded
|
| - ** by this connection. Instead of deleting the journal file it was
|
| - ** kept open and either was truncated to 0 bytes or its header was
|
| - ** overwritten with zeros.
|
| - */
|
| - assert( pPager->nRec==0 );
|
| - assert( pPager->dbOrigSize==0 );
|
| - assert( pPager->pInJournal==0 );
|
| - rc = pager_open_journal(pPager);
|
| - }
|
| -
|
| - PAGERTRACE(("TRANSACTION %d\n", PAGERID(pPager)));
|
| - assert( !isOpen(pPager->jfd) || pPager->journalOff>0 || rc!=SQLITE_OK );
|
| - if( rc!=SQLITE_OK ){
|
| - assert( !pPager->dbModified );
|
| - /* Ignore any IO error that occurs within pager_end_transaction(). The
|
| - ** purpose of this call is to reset the internal state of the pager
|
| - ** sub-system. It doesn't matter if the journal-file is not properly
|
| - ** finalized at this point (since it is not a valid journal file anyway).
|
| - */
|
| - pager_end_transaction(pPager, 0);
|
| - }
|
| - return rc;
|
| -}
|
| -
|
| -/*
|
| -** Mark a single data page as writeable. The page is written into the
|
| -** main journal or sub-journal as required. If the page is written into
|
| -** one of the journals, the corresponding bit is set in the
|
| -** Pager.pInJournal bitvec and the PagerSavepoint.pInSavepoint bitvecs
|
| -** of any open savepoints as appropriate.
|
| -*/
|
| -static int pager_write(PgHdr *pPg){
|
| - void *pData = pPg->pData;
|
| - Pager *pPager = pPg->pPager;
|
| - int rc = SQLITE_OK;
|
| -
|
| - /* This routine is not called unless a transaction has already been
|
| - ** started.
|
| - */
|
| - assert( pPager->state>=PAGER_RESERVED );
|
| -
|
| - /* If an error has been previously detected, we should not be
|
| - ** calling this routine. Repeat the error for robustness.
|
| - */
|
| - if( NEVER(pPager->errCode) ) return pPager->errCode;
|
| -
|
| - /* Higher-level routines never call this function if database is not
|
| - ** writable. But check anyway, just for robustness. */
|
| - if( NEVER(pPager->readOnly) ) return SQLITE_PERM;
|
| -
|
| - assert( !pPager->setMaster );
|
| -
|
| - CHECK_PAGE(pPg);
|
| -
|
| - /* Mark the page as dirty. If the page has already been written
|
| - ** to the journal then we can return right away.
|
| - */
|
| - sqlite3PcacheMakeDirty(pPg);
|
| - if( pageInJournal(pPg) && !subjRequiresPage(pPg) ){
|
| - pPager->dbModified = 1;
|
| - }else{
|
| -
|
| - /* If we get this far, it means that the page needs to be
|
| - ** written to the transaction journal or the ckeckpoint journal
|
| - ** or both.
|
| - **
|
| - ** Higher level routines should have already started a transaction,
|
| - ** which means they have acquired the necessary locks and opened
|
| - ** a rollback journal. Double-check to makes sure this is the case.
|
| - */
|
| - rc = sqlite3PagerBegin(pPager, 0, pPager->subjInMemory);
|
| - if( NEVER(rc!=SQLITE_OK) ){
|
| - return rc;
|
| - }
|
| - if( !isOpen(pPager->jfd) && pPager->journalMode!=PAGER_JOURNALMODE_OFF ){
|
| - assert( pPager->useJournal );
|
| - rc = pager_open_journal(pPager);
|
| - if( rc!=SQLITE_OK ) return rc;
|
| - }
|
| - pPager->dbModified = 1;
|
| -
|
| - /* The transaction journal now exists and we have a RESERVED or an
|
| - ** EXCLUSIVE lock on the main database file. Write the current page to
|
| - ** the transaction journal if it is not there already.
|
| - */
|
| - if( !pageInJournal(pPg) && isOpen(pPager->jfd) ){
|
| - if( pPg->pgno<=pPager->dbOrigSize ){
|
| - u32 cksum;
|
| - char *pData2;
|
| -
|
| - /* We should never write to the journal file the page that
|
| - ** contains the database locks. The following assert verifies
|
| - ** that we do not. */
|
| - assert( pPg->pgno!=PAGER_MJ_PGNO(pPager) );
|
| - CODEC2(pPager, pData, pPg->pgno, 7, return SQLITE_NOMEM, pData2);
|
| - cksum = pager_cksum(pPager, (u8*)pData2);
|
| - rc = write32bits(pPager->jfd, pPager->journalOff, pPg->pgno);
|
| - if( rc==SQLITE_OK ){
|
| - rc = sqlite3OsWrite(pPager->jfd, pData2, pPager->pageSize,
|
| - pPager->journalOff + 4);
|
| - pPager->journalOff += pPager->pageSize+4;
|
| - }
|
| - if( rc==SQLITE_OK ){
|
| - rc = write32bits(pPager->jfd, pPager->journalOff, cksum);
|
| - pPager->journalOff += 4;
|
| - }
|
| - IOTRACE(("JOUT %p %d %lld %d\n", pPager, pPg->pgno,
|
| - pPager->journalOff, pPager->pageSize));
|
| - PAGER_INCR(sqlite3_pager_writej_count);
|
| - PAGERTRACE(("JOURNAL %d page %d needSync=%d hash(%08x)\n",
|
| - PAGERID(pPager), pPg->pgno,
|
| - ((pPg->flags&PGHDR_NEED_SYNC)?1:0), pager_pagehash(pPg)));
|
| -
|
| - /* Even if an IO or diskfull error occurred while journalling the
|
| - ** page in the block above, set the need-sync flag for the page.
|
| - ** Otherwise, when the transaction is rolled back, the logic in
|
| - ** playback_one_page() will think that the page needs to be restored
|
| - ** in the database file. And if an IO error occurs while doing so,
|
| - ** then corruption may follow.
|
| - */
|
| - if( !pPager->noSync ){
|
| - pPg->flags |= PGHDR_NEED_SYNC;
|
| - pPager->needSync = 1;
|
| - }
|
| -
|
| - /* An error has occurred writing to the journal file. The
|
| - ** transaction will be rolled back by the layer above.
|
| - */
|
| - if( rc!=SQLITE_OK ){
|
| - return rc;
|
| - }
|
| -
|
| - pPager->nRec++;
|
| - assert( pPager->pInJournal!=0 );
|
| - rc = sqlite3BitvecSet(pPager->pInJournal, pPg->pgno);
|
| - testcase( rc==SQLITE_NOMEM );
|
| - assert( rc==SQLITE_OK || rc==SQLITE_NOMEM );
|
| - rc |= addToSavepointBitvecs(pPager, pPg->pgno);
|
| - if( rc!=SQLITE_OK ){
|
| - assert( rc==SQLITE_NOMEM );
|
| - return rc;
|
| - }
|
| - }else{
|
| - if( !pPager->journalStarted && !pPager->noSync ){
|
| - pPg->flags |= PGHDR_NEED_SYNC;
|
| - pPager->needSync = 1;
|
| - }
|
| - PAGERTRACE(("APPEND %d page %d needSync=%d\n",
|
| - PAGERID(pPager), pPg->pgno,
|
| - ((pPg->flags&PGHDR_NEED_SYNC)?1:0)));
|
| - }
|
| - }
|
| -
|
| - /* If the statement journal is open and the page is not in it,
|
| - ** then write the current page to the statement journal. Note that
|
| - ** the statement journal format differs from the standard journal format
|
| - ** in that it omits the checksums and the header.
|
| - */
|
| - if( subjRequiresPage(pPg) ){
|
| - rc = subjournalPage(pPg);
|
| - }
|
| - }
|
| -
|
| - /* Update the database size and return.
|
| - */
|
| - assert( pPager->state>=PAGER_SHARED );
|
| - if( pPager->dbSize<pPg->pgno ){
|
| - pPager->dbSize = pPg->pgno;
|
| - }
|
| - return rc;
|
| -}
|
| -
|
| -/*
|
| -** Mark a data page as writeable. This routine must be called before
|
| -** making changes to a page. The caller must check the return value
|
| -** of this function and be careful not to change any page data unless
|
| -** this routine returns SQLITE_OK.
|
| -**
|
| -** The difference between this function and pager_write() is that this
|
| -** function also deals with the special case where 2 or more pages
|
| -** fit on a single disk sector. In this case all co-resident pages
|
| -** must have been written to the journal file before returning.
|
| -**
|
| -** If an error occurs, SQLITE_NOMEM or an IO error code is returned
|
| -** as appropriate. Otherwise, SQLITE_OK.
|
| -*/
|
| -int sqlite3PagerWrite(DbPage *pDbPage){
|
| - int rc = SQLITE_OK;
|
| -
|
| - PgHdr *pPg = pDbPage;
|
| - Pager *pPager = pPg->pPager;
|
| - Pgno nPagePerSector = (pPager->sectorSize/pPager->pageSize);
|
| -
|
| - if( nPagePerSector>1 ){
|
| - Pgno nPageCount; /* Total number of pages in database file */
|
| - Pgno pg1; /* First page of the sector pPg is located on. */
|
| - int nPage; /* Number of pages starting at pg1 to journal */
|
| - int ii; /* Loop counter */
|
| - int needSync = 0; /* True if any page has PGHDR_NEED_SYNC */
|
| -
|
| - /* Set the doNotSync flag to 1. This is because we cannot allow a journal
|
| - ** header to be written between the pages journaled by this function.
|
| - */
|
| - assert( !MEMDB );
|
| - assert( pPager->doNotSync==0 );
|
| - pPager->doNotSync = 1;
|
| -
|
| - /* This trick assumes that both the page-size and sector-size are
|
| - ** an integer power of 2. It sets variable pg1 to the identifier
|
| - ** of the first page of the sector pPg is located on.
|
| - */
|
| - pg1 = ((pPg->pgno-1) & ~(nPagePerSector-1)) + 1;
|
| -
|
| - sqlite3PagerPagecount(pPager, (int *)&nPageCount);
|
| - if( pPg->pgno>nPageCount ){
|
| - nPage = (pPg->pgno - pg1)+1;
|
| - }else if( (pg1+nPagePerSector-1)>nPageCount ){
|
| - nPage = nPageCount+1-pg1;
|
| - }else{
|
| - nPage = nPagePerSector;
|
| - }
|
| - assert(nPage>0);
|
| - assert(pg1<=pPg->pgno);
|
| - assert((pg1+nPage)>pPg->pgno);
|
| -
|
| - for(ii=0; ii<nPage && rc==SQLITE_OK; ii++){
|
| - Pgno pg = pg1+ii;
|
| - PgHdr *pPage;
|
| - if( pg==pPg->pgno || !sqlite3BitvecTest(pPager->pInJournal, pg) ){
|
| - if( pg!=PAGER_MJ_PGNO(pPager) ){
|
| - rc = sqlite3PagerGet(pPager, pg, &pPage);
|
| - if( rc==SQLITE_OK ){
|
| - rc = pager_write(pPage);
|
| - if( pPage->flags&PGHDR_NEED_SYNC ){
|
| - needSync = 1;
|
| - assert(pPager->needSync);
|
| - }
|
| - sqlite3PagerUnref(pPage);
|
| - }
|
| - }
|
| - }else if( (pPage = pager_lookup(pPager, pg))!=0 ){
|
| - if( pPage->flags&PGHDR_NEED_SYNC ){
|
| - needSync = 1;
|
| - }
|
| - sqlite3PagerUnref(pPage);
|
| - }
|
| - }
|
| -
|
| - /* If the PGHDR_NEED_SYNC flag is set for any of the nPage pages
|
| - ** starting at pg1, then it needs to be set for all of them. Because
|
| - ** writing to any of these nPage pages may damage the others, the
|
| - ** journal file must contain sync()ed copies of all of them
|
| - ** before any of them can be written out to the database file.
|
| - */
|
| - if( rc==SQLITE_OK && needSync ){
|
| - assert( !MEMDB && pPager->noSync==0 );
|
| - for(ii=0; ii<nPage; ii++){
|
| - PgHdr *pPage = pager_lookup(pPager, pg1+ii);
|
| - if( pPage ){
|
| - pPage->flags |= PGHDR_NEED_SYNC;
|
| - sqlite3PagerUnref(pPage);
|
| - }
|
| - }
|
| - assert(pPager->needSync);
|
| - }
|
| -
|
| - assert( pPager->doNotSync==1 );
|
| - pPager->doNotSync = 0;
|
| - }else{
|
| - rc = pager_write(pDbPage);
|
| - }
|
| - return rc;
|
| -}
|
| -
|
| -/*
|
| -** Return TRUE if the page given in the argument was previously passed
|
| -** to sqlite3PagerWrite(). In other words, return TRUE if it is ok
|
| -** to change the content of the page.
|
| -*/
|
| -#ifndef NDEBUG
|
| -int sqlite3PagerIswriteable(DbPage *pPg){
|
| - return pPg->flags&PGHDR_DIRTY;
|
| -}
|
| -#endif
|
| -
|
| -/*
|
| -** A call to this routine tells the pager that it is not necessary to
|
| -** write the information on page pPg back to the disk, even though
|
| -** that page might be marked as dirty. This happens, for example, when
|
| -** the page has been added as a leaf of the freelist and so its
|
| -** content no longer matters.
|
| -**
|
| -** The overlying software layer calls this routine when all of the data
|
| -** on the given page is unused. The pager marks the page as clean so
|
| -** that it does not get written to disk.
|
| -**
|
| -** Tests show that this optimization can quadruple the speed of large
|
| -** DELETE operations.
|
| -*/
|
| -void sqlite3PagerDontWrite(PgHdr *pPg){
|
| - Pager *pPager = pPg->pPager;
|
| - if( (pPg->flags&PGHDR_DIRTY) && pPager->nSavepoint==0 ){
|
| - PAGERTRACE(("DONT_WRITE page %d of %d\n", pPg->pgno, PAGERID(pPager)));
|
| - IOTRACE(("CLEAN %p %d\n", pPager, pPg->pgno))
|
| - pPg->flags |= PGHDR_DONT_WRITE;
|
| -#ifdef SQLITE_CHECK_PAGES
|
| - pPg->pageHash = pager_pagehash(pPg);
|
| -#endif
|
| - }
|
| -}
|
| -
|
| -/*
|
| -** This routine is called to increment the value of the database file
|
| -** change-counter, stored as a 4-byte big-endian integer starting at
|
| -** byte offset 24 of the pager file.
|
| -**
|
| -** If the isDirectMode flag is zero, then this is done by calling
|
| -** sqlite3PagerWrite() on page 1, then modifying the contents of the
|
| -** page data. In this case the file will be updated when the current
|
| -** transaction is committed.
|
| -**
|
| -** The isDirectMode flag may only be non-zero if the library was compiled
|
| -** with the SQLITE_ENABLE_ATOMIC_WRITE macro defined. In this case,
|
| -** if isDirect is non-zero, then the database file is updated directly
|
| -** by writing an updated version of page 1 using a call to the
|
| -** sqlite3OsWrite() function.
|
| -*/
|
| -static int pager_incr_changecounter(Pager *pPager, int isDirectMode){
|
| - int rc = SQLITE_OK;
|
| -
|
| - /* Declare and initialize constant integer 'isDirect'. If the
|
| - ** atomic-write optimization is enabled in this build, then isDirect
|
| - ** is initialized to the value passed as the isDirectMode parameter
|
| - ** to this function. Otherwise, it is always set to zero.
|
| - **
|
| - ** The idea is that if the atomic-write optimization is not
|
| - ** enabled at compile time, the compiler can omit the tests of
|
| - ** 'isDirect' below, as well as the block enclosed in the
|
| - ** "if( isDirect )" condition.
|
| - */
|
| -#ifndef SQLITE_ENABLE_ATOMIC_WRITE
|
| -# define DIRECT_MODE 0
|
| - assert( isDirectMode==0 );
|
| - UNUSED_PARAMETER(isDirectMode);
|
| -#else
|
| -# define DIRECT_MODE isDirectMode
|
| -#endif
|
| -
|
| - assert( pPager->state>=PAGER_RESERVED );
|
| - if( !pPager->changeCountDone && ALWAYS(pPager->dbSize>0) ){
|
| - PgHdr *pPgHdr; /* Reference to page 1 */
|
| - u32 change_counter; /* Initial value of change-counter field */
|
| -
|
| - assert( !pPager->tempFile && isOpen(pPager->fd) );
|
| -
|
| - /* Open page 1 of the file for writing. */
|
| - rc = sqlite3PagerGet(pPager, 1, &pPgHdr);
|
| - assert( pPgHdr==0 || rc==SQLITE_OK );
|
| -
|
| - /* If page one was fetched successfully, and this function is not
|
| - ** operating in direct-mode, make page 1 writable. When not in
|
| - ** direct mode, page 1 is always held in cache and hence the PagerGet()
|
| - ** above is always successful - hence the ALWAYS on rc==SQLITE_OK.
|
| - */
|
| - if( !DIRECT_MODE && ALWAYS(rc==SQLITE_OK) ){
|
| - rc = sqlite3PagerWrite(pPgHdr);
|
| - }
|
| -
|
| - if( rc==SQLITE_OK ){
|
| - /* Increment the value just read and write it back to byte 24. */
|
| - change_counter = sqlite3Get4byte((u8*)pPager->dbFileVers);
|
| - change_counter++;
|
| - put32bits(((char*)pPgHdr->pData)+24, change_counter);
|
| -
|
| - /* If running in direct mode, write the contents of page 1 to the file. */
|
| - if( DIRECT_MODE ){
|
| - const void *zBuf = pPgHdr->pData;
|
| - assert( pPager->dbFileSize>0 );
|
| - rc = sqlite3OsWrite(pPager->fd, zBuf, pPager->pageSize, 0);
|
| - if( rc==SQLITE_OK ){
|
| - pPager->changeCountDone = 1;
|
| - }
|
| - }else{
|
| - pPager->changeCountDone = 1;
|
| - }
|
| - }
|
| -
|
| - /* Release the page reference. */
|
| - sqlite3PagerUnref(pPgHdr);
|
| - }
|
| - return rc;
|
| -}
|
| -
|
| -/*
|
| -** Sync the pager file to disk. This is a no-op for in-memory files
|
| -** or pages with the Pager.noSync flag set.
|
| -**
|
| -** If successful, or called on a pager for which it is a no-op, this
|
| -** function returns SQLITE_OK. Otherwise, an IO error code is returned.
|
| -*/
|
| -int sqlite3PagerSync(Pager *pPager){
|
| - int rc; /* Return code */
|
| - assert( !MEMDB );
|
| - if( pPager->noSync ){
|
| - rc = SQLITE_OK;
|
| - }else{
|
| - rc = sqlite3OsSync(pPager->fd, pPager->sync_flags);
|
| - }
|
| - return rc;
|
| -}
|
| -
|
| -/*
|
| -** Sync the database file for the pager pPager. zMaster points to the name
|
| -** of a master journal file that should be written into the individual
|
| -** journal file. zMaster may be NULL, which is interpreted as no master
|
| -** journal (a single database transaction).
|
| -**
|
| -** This routine ensures that:
|
| -**
|
| -** * The database file change-counter is updated,
|
| -** * the journal is synced (unless the atomic-write optimization is used),
|
| -** * all dirty pages are written to the database file,
|
| -** * the database file is truncated (if required), and
|
| -** * the database file synced.
|
| -**
|
| -** The only thing that remains to commit the transaction is to finalize
|
| -** (delete, truncate or zero the first part of) the journal file (or
|
| -** delete the master journal file if specified).
|
| -**
|
| -** Note that if zMaster==NULL, this does not overwrite a previous value
|
| -** passed to an sqlite3PagerCommitPhaseOne() call.
|
| -**
|
| -** If the final parameter - noSync - is true, then the database file itself
|
| -** is not synced. The caller must call sqlite3PagerSync() directly to
|
| -** sync the database file before calling CommitPhaseTwo() to delete the
|
| -** journal file in this case.
|
| -*/
|
| -int sqlite3PagerCommitPhaseOne(
|
| - Pager *pPager, /* Pager object */
|
| - const char *zMaster, /* If not NULL, the master journal name */
|
| - int noSync /* True to omit the xSync on the db file */
|
| -){
|
| - int rc = SQLITE_OK; /* Return code */
|
| -
|
| - /* The dbOrigSize is never set if journal_mode=OFF */
|
| - assert( pPager->journalMode!=PAGER_JOURNALMODE_OFF || pPager->dbOrigSize==0 );
|
| -
|
| - /* If a prior error occurred, this routine should not be called. ROLLBACK
|
| - ** is the appropriate response to an error, not COMMIT. Guard against
|
| - ** coding errors by repeating the prior error. */
|
| - if( NEVER(pPager->errCode) ) return pPager->errCode;
|
| -
|
| - PAGERTRACE(("DATABASE SYNC: File=%s zMaster=%s nSize=%d\n",
|
| - pPager->zFilename, zMaster, pPager->dbSize));
|
| -
|
| - if( MEMDB && pPager->dbModified ){
|
| - /* If this is an in-memory db, or no pages have been written to, or this
|
| - ** function has already been called, it is mostly a no-op. However, any
|
| - ** backup in progress needs to be restarted.
|
| - */
|
| - sqlite3BackupRestart(pPager->pBackup);
|
| - }else if( pPager->state!=PAGER_SYNCED && pPager->dbModified ){
|
| -
|
| - /* The following block updates the change-counter. Exactly how it
|
| - ** does this depends on whether or not the atomic-update optimization
|
| - ** was enabled at compile time, and if this transaction meets the
|
| - ** runtime criteria to use the operation:
|
| - **
|
| - ** * The file-system supports the atomic-write property for
|
| - ** blocks of size page-size, and
|
| - ** * This commit is not part of a multi-file transaction, and
|
| - ** * Exactly one page has been modified and store in the journal file.
|
| - **
|
| - ** If the optimization was not enabled at compile time, then the
|
| - ** pager_incr_changecounter() function is called to update the change
|
| - ** counter in 'indirect-mode'. If the optimization is compiled in but
|
| - ** is not applicable to this transaction, call sqlite3JournalCreate()
|
| - ** to make sure the journal file has actually been created, then call
|
| - ** pager_incr_changecounter() to update the change-counter in indirect
|
| - ** mode.
|
| - **
|
| - ** Otherwise, if the optimization is both enabled and applicable,
|
| - ** then call pager_incr_changecounter() to update the change-counter
|
| - ** in 'direct' mode. In this case the journal file will never be
|
| - ** created for this transaction.
|
| - */
|
| -#ifdef SQLITE_ENABLE_ATOMIC_WRITE
|
| - PgHdr *pPg;
|
| - assert( isOpen(pPager->jfd) || pPager->journalMode==PAGER_JOURNALMODE_OFF );
|
| - if( !zMaster && isOpen(pPager->jfd)
|
| - && pPager->journalOff==jrnlBufferSize(pPager)
|
| - && pPager->dbSize>=pPager->dbFileSize
|
| - && (0==(pPg = sqlite3PcacheDirtyList(pPager->pPCache)) || 0==pPg->pDirty)
|
| - ){
|
| - /* Update the db file change counter via the direct-write method. The
|
| - ** following call will modify the in-memory representation of page 1
|
| - ** to include the updated change counter and then write page 1
|
| - ** directly to the database file. Because of the atomic-write
|
| - ** property of the host file-system, this is safe.
|
| - */
|
| - rc = pager_incr_changecounter(pPager, 1);
|
| - }else{
|
| - rc = sqlite3JournalCreate(pPager->jfd);
|
| - if( rc==SQLITE_OK ){
|
| - rc = pager_incr_changecounter(pPager, 0);
|
| - }
|
| - }
|
| -#else
|
| - rc = pager_incr_changecounter(pPager, 0);
|
| -#endif
|
| - if( rc!=SQLITE_OK ) goto commit_phase_one_exit;
|
| -
|
| - /* If this transaction has made the database smaller, then all pages
|
| - ** being discarded by the truncation must be written to the journal
|
| - ** file. This can only happen in auto-vacuum mode.
|
| - **
|
| - ** Before reading the pages with page numbers larger than the
|
| - ** current value of Pager.dbSize, set dbSize back to the value
|
| - ** that it took at the start of the transaction. Otherwise, the
|
| - ** calls to sqlite3PagerGet() return zeroed pages instead of
|
| - ** reading data from the database file.
|
| - **
|
| - ** When journal_mode==OFF the dbOrigSize is always zero, so this
|
| - ** block never runs if journal_mode=OFF.
|
| - */
|
| -#ifndef SQLITE_OMIT_AUTOVACUUM
|
| - if( pPager->dbSize<pPager->dbOrigSize
|
| - && ALWAYS(pPager->journalMode!=PAGER_JOURNALMODE_OFF)
|
| - ){
|
| - Pgno i; /* Iterator variable */
|
| - const Pgno iSkip = PAGER_MJ_PGNO(pPager); /* Pending lock page */
|
| - const Pgno dbSize = pPager->dbSize; /* Database image size */
|
| - pPager->dbSize = pPager->dbOrigSize;
|
| - for( i=dbSize+1; i<=pPager->dbOrigSize; i++ ){
|
| - if( !sqlite3BitvecTest(pPager->pInJournal, i) && i!=iSkip ){
|
| - PgHdr *pPage; /* Page to journal */
|
| - rc = sqlite3PagerGet(pPager, i, &pPage);
|
| - if( rc!=SQLITE_OK ) goto commit_phase_one_exit;
|
| - rc = sqlite3PagerWrite(pPage);
|
| - sqlite3PagerUnref(pPage);
|
| - if( rc!=SQLITE_OK ) goto commit_phase_one_exit;
|
| - }
|
| - }
|
| - pPager->dbSize = dbSize;
|
| - }
|
| -#endif
|
| -
|
| - /* Write the master journal name into the journal file. If a master
|
| - ** journal file name has already been written to the journal file,
|
| - ** or if zMaster is NULL (no master journal), then this call is a no-op.
|
| - */
|
| - rc = writeMasterJournal(pPager, zMaster);
|
| - if( rc!=SQLITE_OK ) goto commit_phase_one_exit;
|
| -
|
| - /* Sync the journal file. If the atomic-update optimization is being
|
| - ** used, this call will not create the journal file or perform any
|
| - ** real IO.
|
| - */
|
| - rc = syncJournal(pPager);
|
| - if( rc!=SQLITE_OK ) goto commit_phase_one_exit;
|
| -
|
| - /* Write all dirty pages to the database file. */
|
| - rc = pager_write_pagelist(sqlite3PcacheDirtyList(pPager->pPCache));
|
| - if( rc!=SQLITE_OK ){
|
| - assert( rc!=SQLITE_IOERR_BLOCKED );
|
| - goto commit_phase_one_exit;
|
| - }
|
| - sqlite3PcacheCleanAll(pPager->pPCache);
|
| -
|
| - /* If the file on disk is not the same size as the database image,
|
| - ** then use pager_truncate to grow or shrink the file here.
|
| - */
|
| - if( pPager->dbSize!=pPager->dbFileSize ){
|
| - Pgno nNew = pPager->dbSize - (pPager->dbSize==PAGER_MJ_PGNO(pPager));
|
| - assert( pPager->state>=PAGER_EXCLUSIVE );
|
| - rc = pager_truncate(pPager, nNew);
|
| - if( rc!=SQLITE_OK ) goto commit_phase_one_exit;
|
| - }
|
| -
|
| - /* Finally, sync the database file. */
|
| - if( !pPager->noSync && !noSync ){
|
| - rc = sqlite3OsSync(pPager->fd, pPager->sync_flags);
|
| - }
|
| - IOTRACE(("DBSYNC %p\n", pPager))
|
| -
|
| - pPager->state = PAGER_SYNCED;
|
| - }
|
| -
|
| -commit_phase_one_exit:
|
| - return rc;
|
| -}
|
| -
|
| -
|
| -/*
|
| -** When this function is called, the database file has been completely
|
| -** updated to reflect the changes made by the current transaction and
|
| -** synced to disk. The journal file still exists in the file-system
|
| -** though, and if a failure occurs at this point it will eventually
|
| -** be used as a hot-journal and the current transaction rolled back.
|
| -**
|
| -** This function finalizes the journal file, either by deleting,
|
| -** truncating or partially zeroing it, so that it cannot be used
|
| -** for hot-journal rollback. Once this is done the transaction is
|
| -** irrevocably committed.
|
| -**
|
| -** If an error occurs, an IO error code is returned and the pager
|
| -** moves into the error state. Otherwise, SQLITE_OK is returned.
|
| -*/
|
| -int sqlite3PagerCommitPhaseTwo(Pager *pPager){
|
| - int rc = SQLITE_OK; /* Return code */
|
| -
|
| - /* This routine should not be called if a prior error has occurred.
|
| - ** But if (due to a coding error elsewhere in the system) it does get
|
| - ** called, just return the same error code without doing anything. */
|
| - if( NEVER(pPager->errCode) ) return pPager->errCode;
|
| -
|
| - /* This function should not be called if the pager is not in at least
|
| - ** PAGER_RESERVED state. And indeed SQLite never does this. But it is
|
| - ** nice to have this defensive test here anyway.
|
| - */
|
| - if( NEVER(pPager->state<PAGER_RESERVED) ) return SQLITE_ERROR;
|
| -
|
| - /* An optimization. If the database was not actually modified during
|
| - ** this transaction, the pager is running in exclusive-mode and is
|
| - ** using persistent journals, then this function is a no-op.
|
| - **
|
| - ** The start of the journal file currently contains a single journal
|
| - ** header with the nRec field set to 0. If such a journal is used as
|
| - ** a hot-journal during hot-journal rollback, 0 changes will be made
|
| - ** to the database file. So there is no need to zero the journal
|
| - ** header. Since the pager is in exclusive mode, there is no need
|
| - ** to drop any locks either.
|
| - */
|
| - if( pPager->dbModified==0 && pPager->exclusiveMode
|
| - && pPager->journalMode==PAGER_JOURNALMODE_PERSIST
|
| - ){
|
| - assert( pPager->journalOff==JOURNAL_HDR_SZ(pPager) );
|
| - return SQLITE_OK;
|
| - }
|
| -
|
| - PAGERTRACE(("COMMIT %d\n", PAGERID(pPager)));
|
| - assert( pPager->state==PAGER_SYNCED || MEMDB || !pPager->dbModified );
|
| - rc = pager_end_transaction(pPager, pPager->setMaster);
|
| - return pager_error(pPager, rc);
|
| -}
|
| -
|
| -/*
|
| -** Rollback all changes. The database falls back to PAGER_SHARED mode.
|
| -**
|
| -** This function performs two tasks:
|
| -**
|
| -** 1) It rolls back the journal file, restoring all database file and
|
| -** in-memory cache pages to the state they were in when the transaction
|
| -** was opened, and
|
| -** 2) It finalizes the journal file, so that it is not used for hot
|
| -** rollback at any point in the future.
|
| -**
|
| -** subject to the following qualifications:
|
| -**
|
| -** * If the journal file is not yet open when this function is called,
|
| -** then only (2) is performed. In this case there is no journal file
|
| -** to roll back.
|
| -**
|
| -** * If in an error state other than SQLITE_FULL, then task (1) is
|
| -** performed. If successful, task (2). Regardless of the outcome
|
| -** of either, the error state error code is returned to the caller
|
| -** (i.e. either SQLITE_IOERR or SQLITE_CORRUPT).
|
| -**
|
| -** * If the pager is in PAGER_RESERVED state, then attempt (1). Whether
|
| -** or not (1) is succussful, also attempt (2). If successful, return
|
| -** SQLITE_OK. Otherwise, enter the error state and return the first
|
| -** error code encountered.
|
| -**
|
| -** In this case there is no chance that the database was written to.
|
| -** So is safe to finalize the journal file even if the playback
|
| -** (operation 1) failed. However the pager must enter the error state
|
| -** as the contents of the in-memory cache are now suspect.
|
| -**
|
| -** * Finally, if in PAGER_EXCLUSIVE state, then attempt (1). Only
|
| -** attempt (2) if (1) is successful. Return SQLITE_OK if successful,
|
| -** otherwise enter the error state and return the error code from the
|
| -** failing operation.
|
| -**
|
| -** In this case the database file may have been written to. So if the
|
| -** playback operation did not succeed it would not be safe to finalize
|
| -** the journal file. It needs to be left in the file-system so that
|
| -** some other process can use it to restore the database state (by
|
| -** hot-journal rollback).
|
| -*/
|
| -int sqlite3PagerRollback(Pager *pPager){
|
| - int rc = SQLITE_OK; /* Return code */
|
| - PAGERTRACE(("ROLLBACK %d\n", PAGERID(pPager)));
|
| - if( !pPager->dbModified || !isOpen(pPager->jfd) ){
|
| - rc = pager_end_transaction(pPager, pPager->setMaster);
|
| - }else if( pPager->errCode && pPager->errCode!=SQLITE_FULL ){
|
| - if( pPager->state>=PAGER_EXCLUSIVE ){
|
| - pager_playback(pPager, 0);
|
| - }
|
| - rc = pPager->errCode;
|
| - }else{
|
| - if( pPager->state==PAGER_RESERVED ){
|
| - int rc2;
|
| - rc = pager_playback(pPager, 0);
|
| - rc2 = pager_end_transaction(pPager, pPager->setMaster);
|
| - if( rc==SQLITE_OK ){
|
| - rc = rc2;
|
| - }
|
| - }else{
|
| - rc = pager_playback(pPager, 0);
|
| - }
|
| -
|
| - if( !MEMDB ){
|
| - pPager->dbSizeValid = 0;
|
| - }
|
| -
|
| - /* If an error occurs during a ROLLBACK, we can no longer trust the pager
|
| - ** cache. So call pager_error() on the way out to make any error
|
| - ** persistent.
|
| - */
|
| - rc = pager_error(pPager, rc);
|
| - }
|
| - return rc;
|
| -}
|
| -
|
| -/*
|
| -** Return TRUE if the database file is opened read-only. Return FALSE
|
| -** if the database is (in theory) writable.
|
| -*/
|
| -u8 sqlite3PagerIsreadonly(Pager *pPager){
|
| - return pPager->readOnly;
|
| -}
|
| -
|
| -/*
|
| -** Return the number of references to the pager.
|
| -*/
|
| -int sqlite3PagerRefcount(Pager *pPager){
|
| - return sqlite3PcacheRefCount(pPager->pPCache);
|
| -}
|
| -
|
| -/*
|
| -** Return the number of references to the specified page.
|
| -*/
|
| -int sqlite3PagerPageRefcount(DbPage *pPage){
|
| - return sqlite3PcachePageRefcount(pPage);
|
| -}
|
| -
|
| -#ifdef SQLITE_TEST
|
| -/*
|
| -** This routine is used for testing and analysis only.
|
| -*/
|
| -int *sqlite3PagerStats(Pager *pPager){
|
| - static int a[11];
|
| - a[0] = sqlite3PcacheRefCount(pPager->pPCache);
|
| - a[1] = sqlite3PcachePagecount(pPager->pPCache);
|
| - a[2] = sqlite3PcacheGetCachesize(pPager->pPCache);
|
| - a[3] = pPager->dbSizeValid ? (int) pPager->dbSize : -1;
|
| - a[4] = pPager->state;
|
| - a[5] = pPager->errCode;
|
| - a[6] = pPager->nHit;
|
| - a[7] = pPager->nMiss;
|
| - a[8] = 0; /* Used to be pPager->nOvfl */
|
| - a[9] = pPager->nRead;
|
| - a[10] = pPager->nWrite;
|
| - return a;
|
| -}
|
| -#endif
|
| -
|
| -/*
|
| -** Return true if this is an in-memory pager.
|
| -*/
|
| -int sqlite3PagerIsMemdb(Pager *pPager){
|
| - return MEMDB;
|
| -}
|
| -
|
| -/*
|
| -** Check that there are at least nSavepoint savepoints open. If there are
|
| -** currently less than nSavepoints open, then open one or more savepoints
|
| -** to make up the difference. If the number of savepoints is already
|
| -** equal to nSavepoint, then this function is a no-op.
|
| -**
|
| -** If a memory allocation fails, SQLITE_NOMEM is returned. If an error
|
| -** occurs while opening the sub-journal file, then an IO error code is
|
| -** returned. Otherwise, SQLITE_OK.
|
| -*/
|
| -int sqlite3PagerOpenSavepoint(Pager *pPager, int nSavepoint){
|
| - int rc = SQLITE_OK; /* Return code */
|
| - int nCurrent = pPager->nSavepoint; /* Current number of savepoints */
|
| -
|
| - if( nSavepoint>nCurrent && pPager->useJournal ){
|
| - int ii; /* Iterator variable */
|
| - PagerSavepoint *aNew; /* New Pager.aSavepoint array */
|
| -
|
| - /* Either there is no active journal or the sub-journal is open or
|
| - ** the journal is always stored in memory */
|
| - assert( pPager->nSavepoint==0 || isOpen(pPager->sjfd) ||
|
| - pPager->journalMode==PAGER_JOURNALMODE_MEMORY );
|
| -
|
| - /* Grow the Pager.aSavepoint array using realloc(). Return SQLITE_NOMEM
|
| - ** if the allocation fails. Otherwise, zero the new portion in case a
|
| - ** malloc failure occurs while populating it in the for(...) loop below.
|
| - */
|
| - aNew = (PagerSavepoint *)sqlite3Realloc(
|
| - pPager->aSavepoint, sizeof(PagerSavepoint)*nSavepoint
|
| - );
|
| - if( !aNew ){
|
| - return SQLITE_NOMEM;
|
| - }
|
| - memset(&aNew[nCurrent], 0, (nSavepoint-nCurrent) * sizeof(PagerSavepoint));
|
| - pPager->aSavepoint = aNew;
|
| - pPager->nSavepoint = nSavepoint;
|
| -
|
| - /* Populate the PagerSavepoint structures just allocated. */
|
| - for(ii=nCurrent; ii<nSavepoint; ii++){
|
| - assert( pPager->dbSizeValid );
|
| - aNew[ii].nOrig = pPager->dbSize;
|
| - if( isOpen(pPager->jfd) && ALWAYS(pPager->journalOff>0) ){
|
| - aNew[ii].iOffset = pPager->journalOff;
|
| - }else{
|
| - aNew[ii].iOffset = JOURNAL_HDR_SZ(pPager);
|
| - }
|
| - aNew[ii].iSubRec = pPager->nSubRec;
|
| - aNew[ii].pInSavepoint = sqlite3BitvecCreate(pPager->dbSize);
|
| - if( !aNew[ii].pInSavepoint ){
|
| - return SQLITE_NOMEM;
|
| - }
|
| - }
|
| -
|
| - /* Open the sub-journal, if it is not already opened. */
|
| - rc = openSubJournal(pPager);
|
| - assertTruncateConstraint(pPager);
|
| - }
|
| -
|
| - return rc;
|
| -}
|
| -
|
| -/*
|
| -** This function is called to rollback or release (commit) a savepoint.
|
| -** The savepoint to release or rollback need not be the most recently
|
| -** created savepoint.
|
| -**
|
| -** Parameter op is always either SAVEPOINT_ROLLBACK or SAVEPOINT_RELEASE.
|
| -** If it is SAVEPOINT_RELEASE, then release and destroy the savepoint with
|
| -** index iSavepoint. If it is SAVEPOINT_ROLLBACK, then rollback all changes
|
| -** that have occurred since the specified savepoint was created.
|
| -**
|
| -** The savepoint to rollback or release is identified by parameter
|
| -** iSavepoint. A value of 0 means to operate on the outermost savepoint
|
| -** (the first created). A value of (Pager.nSavepoint-1) means operate
|
| -** on the most recently created savepoint. If iSavepoint is greater than
|
| -** (Pager.nSavepoint-1), then this function is a no-op.
|
| -**
|
| -** If a negative value is passed to this function, then the current
|
| -** transaction is rolled back. This is different to calling
|
| -** sqlite3PagerRollback() because this function does not terminate
|
| -** the transaction or unlock the database, it just restores the
|
| -** contents of the database to its original state.
|
| -**
|
| -** In any case, all savepoints with an index greater than iSavepoint
|
| -** are destroyed. If this is a release operation (op==SAVEPOINT_RELEASE),
|
| -** then savepoint iSavepoint is also destroyed.
|
| -**
|
| -** This function may return SQLITE_NOMEM if a memory allocation fails,
|
| -** or an IO error code if an IO error occurs while rolling back a
|
| -** savepoint. If no errors occur, SQLITE_OK is returned.
|
| -*/
|
| -int sqlite3PagerSavepoint(Pager *pPager, int op, int iSavepoint){
|
| - int rc = SQLITE_OK;
|
| -
|
| - assert( op==SAVEPOINT_RELEASE || op==SAVEPOINT_ROLLBACK );
|
| - assert( iSavepoint>=0 || op==SAVEPOINT_ROLLBACK );
|
| -
|
| - if( iSavepoint<pPager->nSavepoint ){
|
| - int ii; /* Iterator variable */
|
| - int nNew; /* Number of remaining savepoints after this op. */
|
| -
|
| - /* Figure out how many savepoints will still be active after this
|
| - ** operation. Store this value in nNew. Then free resources associated
|
| - ** with any savepoints that are destroyed by this operation.
|
| - */
|
| - nNew = iSavepoint + (op==SAVEPOINT_ROLLBACK);
|
| - for(ii=nNew; ii<pPager->nSavepoint; ii++){
|
| - sqlite3BitvecDestroy(pPager->aSavepoint[ii].pInSavepoint);
|
| - }
|
| - pPager->nSavepoint = nNew;
|
| -
|
| - /* If this is a rollback operation, playback the specified savepoint.
|
| - ** If this is a temp-file, it is possible that the journal file has
|
| - ** not yet been opened. In this case there have been no changes to
|
| - ** the database file, so the playback operation can be skipped.
|
| - */
|
| - if( op==SAVEPOINT_ROLLBACK && isOpen(pPager->jfd) ){
|
| - PagerSavepoint *pSavepoint = (nNew==0)?0:&pPager->aSavepoint[nNew-1];
|
| - rc = pagerPlaybackSavepoint(pPager, pSavepoint);
|
| - assert(rc!=SQLITE_DONE);
|
| - }
|
| -
|
| - /* If this is a release of the outermost savepoint, truncate
|
| - ** the sub-journal to zero bytes in size. */
|
| - if( nNew==0 && op==SAVEPOINT_RELEASE && isOpen(pPager->sjfd) ){
|
| - assert( rc==SQLITE_OK );
|
| - rc = sqlite3OsTruncate(pPager->sjfd, 0);
|
| - pPager->nSubRec = 0;
|
| - }
|
| - }
|
| - return rc;
|
| -}
|
| -
|
| -/*
|
| -** Return the full pathname of the database file.
|
| -*/
|
| -const char *sqlite3PagerFilename(Pager *pPager){
|
| - return pPager->zFilename;
|
| -}
|
| -
|
| -/*
|
| -** Return the VFS structure for the pager.
|
| -*/
|
| -const sqlite3_vfs *sqlite3PagerVfs(Pager *pPager){
|
| - return pPager->pVfs;
|
| -}
|
| -
|
| -/*
|
| -** Return the file handle for the database file associated
|
| -** with the pager. This might return NULL if the file has
|
| -** not yet been opened.
|
| -*/
|
| -sqlite3_file *sqlite3PagerFile(Pager *pPager){
|
| - return pPager->fd;
|
| -}
|
| -
|
| -/*
|
| -** Return the full pathname of the journal file.
|
| -*/
|
| -const char *sqlite3PagerJournalname(Pager *pPager){
|
| - return pPager->zJournal;
|
| -}
|
| -
|
| -/*
|
| -** Return true if fsync() calls are disabled for this pager. Return FALSE
|
| -** if fsync()s are executed normally.
|
| -*/
|
| -int sqlite3PagerNosync(Pager *pPager){
|
| - return pPager->noSync;
|
| -}
|
| -
|
| -#ifdef SQLITE_HAS_CODEC
|
| -/*
|
| -** Set or retrieve the codec for this pager
|
| -*/
|
| -static void sqlite3PagerSetCodec(
|
| - Pager *pPager,
|
| - void *(*xCodec)(void*,void*,Pgno,int),
|
| - void (*xCodecSizeChng)(void*,int,int),
|
| - void (*xCodecFree)(void*),
|
| - void *pCodec
|
| -){
|
| - if( pPager->xCodecFree ) pPager->xCodecFree(pPager->pCodec);
|
| - pPager->xCodec = xCodec;
|
| - pPager->xCodecSizeChng = xCodecSizeChng;
|
| - pPager->xCodecFree = xCodecFree;
|
| - pPager->pCodec = pCodec;
|
| - pagerReportSize(pPager);
|
| -}
|
| -static void *sqlite3PagerGetCodec(Pager *pPager){
|
| - return pPager->pCodec;
|
| -}
|
| -#endif
|
| -
|
| -#ifndef SQLITE_OMIT_AUTOVACUUM
|
| -/*
|
| -** Move the page pPg to location pgno in the file.
|
| -**
|
| -** There must be no references to the page previously located at
|
| -** pgno (which we call pPgOld) though that page is allowed to be
|
| -** in cache. If the page previously located at pgno is not already
|
| -** in the rollback journal, it is not put there by by this routine.
|
| -**
|
| -** References to the page pPg remain valid. Updating any
|
| -** meta-data associated with pPg (i.e. data stored in the nExtra bytes
|
| -** allocated along with the page) is the responsibility of the caller.
|
| -**
|
| -** A transaction must be active when this routine is called. It used to be
|
| -** required that a statement transaction was not active, but this restriction
|
| -** has been removed (CREATE INDEX needs to move a page when a statement
|
| -** transaction is active).
|
| -**
|
| -** If the fourth argument, isCommit, is non-zero, then this page is being
|
| -** moved as part of a database reorganization just before the transaction
|
| -** is being committed. In this case, it is guaranteed that the database page
|
| -** pPg refers to will not be written to again within this transaction.
|
| -**
|
| -** This function may return SQLITE_NOMEM or an IO error code if an error
|
| -** occurs. Otherwise, it returns SQLITE_OK.
|
| -*/
|
| -int sqlite3PagerMovepage(Pager *pPager, DbPage *pPg, Pgno pgno, int isCommit){
|
| - PgHdr *pPgOld; /* The page being overwritten. */
|
| - Pgno needSyncPgno = 0; /* Old value of pPg->pgno, if sync is required */
|
| - int rc; /* Return code */
|
| - Pgno origPgno; /* The original page number */
|
| -
|
| - assert( pPg->nRef>0 );
|
| -
|
| - /* If the page being moved is dirty and has not been saved by the latest
|
| - ** savepoint, then save the current contents of the page into the
|
| - ** sub-journal now. This is required to handle the following scenario:
|
| - **
|
| - ** BEGIN;
|
| - ** <journal page X, then modify it in memory>
|
| - ** SAVEPOINT one;
|
| - ** <Move page X to location Y>
|
| - ** ROLLBACK TO one;
|
| - **
|
| - ** If page X were not written to the sub-journal here, it would not
|
| - ** be possible to restore its contents when the "ROLLBACK TO one"
|
| - ** statement were is processed.
|
| - **
|
| - ** subjournalPage() may need to allocate space to store pPg->pgno into
|
| - ** one or more savepoint bitvecs. This is the reason this function
|
| - ** may return SQLITE_NOMEM.
|
| - */
|
| - if( pPg->flags&PGHDR_DIRTY
|
| - && subjRequiresPage(pPg)
|
| - && SQLITE_OK!=(rc = subjournalPage(pPg))
|
| - ){
|
| - return rc;
|
| - }
|
| -
|
| - PAGERTRACE(("MOVE %d page %d (needSync=%d) moves to %d\n",
|
| - PAGERID(pPager), pPg->pgno, (pPg->flags&PGHDR_NEED_SYNC)?1:0, pgno));
|
| - IOTRACE(("MOVE %p %d %d\n", pPager, pPg->pgno, pgno))
|
| -
|
| - /* If the journal needs to be sync()ed before page pPg->pgno can
|
| - ** be written to, store pPg->pgno in local variable needSyncPgno.
|
| - **
|
| - ** If the isCommit flag is set, there is no need to remember that
|
| - ** the journal needs to be sync()ed before database page pPg->pgno
|
| - ** can be written to. The caller has already promised not to write to it.
|
| - */
|
| - if( (pPg->flags&PGHDR_NEED_SYNC) && !isCommit ){
|
| - needSyncPgno = pPg->pgno;
|
| - assert( pageInJournal(pPg) || pPg->pgno>pPager->dbOrigSize );
|
| - assert( pPg->flags&PGHDR_DIRTY );
|
| - assert( pPager->needSync );
|
| - }
|
| -
|
| - /* If the cache contains a page with page-number pgno, remove it
|
| - ** from its hash chain. Also, if the PgHdr.needSync was set for
|
| - ** page pgno before the 'move' operation, it needs to be retained
|
| - ** for the page moved there.
|
| - */
|
| - pPg->flags &= ~PGHDR_NEED_SYNC;
|
| - pPgOld = pager_lookup(pPager, pgno);
|
| - assert( !pPgOld || pPgOld->nRef==1 );
|
| - if( pPgOld ){
|
| - pPg->flags |= (pPgOld->flags&PGHDR_NEED_SYNC);
|
| - sqlite3PcacheDrop(pPgOld);
|
| - }
|
| -
|
| - origPgno = pPg->pgno;
|
| - sqlite3PcacheMove(pPg, pgno);
|
| - sqlite3PcacheMakeDirty(pPg);
|
| - pPager->dbModified = 1;
|
| -
|
| - if( needSyncPgno ){
|
| - /* If needSyncPgno is non-zero, then the journal file needs to be
|
| - ** sync()ed before any data is written to database file page needSyncPgno.
|
| - ** Currently, no such page exists in the page-cache and the
|
| - ** "is journaled" bitvec flag has been set. This needs to be remedied by
|
| - ** loading the page into the pager-cache and setting the PgHdr.needSync
|
| - ** flag.
|
| - **
|
| - ** If the attempt to load the page into the page-cache fails, (due
|
| - ** to a malloc() or IO failure), clear the bit in the pInJournal[]
|
| - ** array. Otherwise, if the page is loaded and written again in
|
| - ** this transaction, it may be written to the database file before
|
| - ** it is synced into the journal file. This way, it may end up in
|
| - ** the journal file twice, but that is not a problem.
|
| - **
|
| - ** The sqlite3PagerGet() call may cause the journal to sync. So make
|
| - ** sure the Pager.needSync flag is set too.
|
| - */
|
| - PgHdr *pPgHdr;
|
| - assert( pPager->needSync );
|
| - rc = sqlite3PagerGet(pPager, needSyncPgno, &pPgHdr);
|
| - if( rc!=SQLITE_OK ){
|
| - if( needSyncPgno<=pPager->dbOrigSize ){
|
| - assert( pPager->pTmpSpace!=0 );
|
| - sqlite3BitvecClear(pPager->pInJournal, needSyncPgno, pPager->pTmpSpace);
|
| - }
|
| - return rc;
|
| - }
|
| - pPager->needSync = 1;
|
| - assert( pPager->noSync==0 && !MEMDB );
|
| - pPgHdr->flags |= PGHDR_NEED_SYNC;
|
| - sqlite3PcacheMakeDirty(pPgHdr);
|
| - sqlite3PagerUnref(pPgHdr);
|
| - }
|
| -
|
| - /*
|
| - ** For an in-memory database, make sure the original page continues
|
| - ** to exist, in case the transaction needs to roll back. We allocate
|
| - ** the page now, instead of at rollback, because we can better deal
|
| - ** with an out-of-memory error now. Ticket #3761.
|
| - */
|
| - if( MEMDB ){
|
| - DbPage *pNew;
|
| - rc = sqlite3PagerAcquire(pPager, origPgno, &pNew, 1);
|
| - if( rc!=SQLITE_OK ){
|
| - sqlite3PcacheMove(pPg, origPgno);
|
| - return rc;
|
| - }
|
| - sqlite3PagerUnref(pNew);
|
| - }
|
| -
|
| - return SQLITE_OK;
|
| -}
|
| -#endif
|
| -
|
| -/* Begin preload-cache.patch for Chromium */
|
| -/**
|
| -** When making large allocations, there is no need to stress the heap and
|
| -** potentially hold its lock while we allocate a bunch of memory. If we know
|
| -** the allocation will be large, go directly to the OS instead of the heap.
|
| -**/
|
| -static void* allocLarge(size_t size) {
|
| -#if SQLITE_OS_WIN
|
| - return VirtualAlloc(NULL, size, MEM_COMMIT | MEM_RESERVE, PAGE_READWRITE);
|
| -#else
|
| - return sqlite3Malloc(size);
|
| -#endif
|
| -}
|
| -
|
| -static void freeLarge(void* ptr) {
|
| -#if SQLITE_OS_WIN
|
| - VirtualFree(ptr, 0, MEM_RELEASE);
|
| -#else
|
| - sqlite3_free(ptr);
|
| -#endif
|
| -}
|
| -
|
| -/**
|
| -** Addition: This will attempt to populate the database cache with
|
| -** the first N bytes of the file, where N is the total size of the cache.
|
| -** Because we can load this as one chunk from the disk, this is much faster
|
| -** than loading a subset of the pages one at a time in random order.
|
| -**
|
| -** The pager must be initialized before this function is called. This means a
|
| -* statement must be open that has initialized the pager and is keeping the
|
| -** cache in memory.
|
| -**/
|
| -int sqlite3PagerLoadall(Pager* pPager)
|
| -{
|
| - int i;
|
| - int rc;
|
| - int nMax;
|
| - int loadSize;
|
| - int loadPages;
|
| - unsigned char *fileData;
|
| -
|
| - if (pPager->dbSize < 0 || pPager->pageSize < 0) {
|
| - /* pager not initialized, this means a statement is not open */
|
| - return SQLITE_MISUSE;
|
| - }
|
| -
|
| - /* compute sizes */
|
| - nMax = sqlite3PcacheGetCachesize(pPager->pPCache);
|
| - if (nMax < pPager->dbSize)
|
| - loadPages = nMax;
|
| - else
|
| - loadPages = pPager->dbSize;
|
| - loadSize = loadPages * pPager->pageSize;
|
| -
|
| - /* load the file as one chunk */
|
| - fileData = allocLarge(loadSize);
|
| - if (! fileData)
|
| - return SQLITE_NOMEM;
|
| - rc = sqlite3OsRead(pPager->fd, fileData, loadSize, 0);
|
| - if (rc != SQLITE_OK) {
|
| - freeLarge(fileData);
|
| - return rc;
|
| - }
|
| -
|
| - /* Copy the data to each page. Note that the page numbers we pass to _get
|
| - * are one-based, 0 is a marker for no page. We also need to check that we
|
| - * haven't loaded more pages than the cache can hold total. There may have
|
| - * already been a few pages loaded before, so we may fill the cache before
|
| - * loading all of the pages we want to.
|
| - */
|
| - for(i=1;
|
| - i <= loadPages && sqlite3PcachePagecount(pPager->pPCache) < nMax;
|
| - i++) {
|
| - DbPage *pPage = 0;
|
| - rc = sqlite3PagerAcquire2(pPager, i, &pPage, 0,
|
| - &fileData[(i-1)*(i64)pPager->pageSize]);
|
| - if (rc != SQLITE_OK)
|
| - break;
|
| - sqlite3PagerUnref(pPage);
|
| - }
|
| - freeLarge(fileData);
|
| - return SQLITE_OK;
|
| -}
|
| -/* End preload-cache.patch for Chromium */
|
| -
|
| -/*
|
| -** Return a pointer to the data for the specified page.
|
| -*/
|
| -void *sqlite3PagerGetData(DbPage *pPg){
|
| - assert( pPg->nRef>0 || pPg->pPager->memDb );
|
| - return pPg->pData;
|
| -}
|
| -
|
| -/*
|
| -** Return a pointer to the Pager.nExtra bytes of "extra" space
|
| -** allocated along with the specified page.
|
| -*/
|
| -void *sqlite3PagerGetExtra(DbPage *pPg){
|
| - return pPg->pExtra;
|
| -}
|
| -
|
| -/*
|
| -** Get/set the locking-mode for this pager. Parameter eMode must be one
|
| -** of PAGER_LOCKINGMODE_QUERY, PAGER_LOCKINGMODE_NORMAL or
|
| -** PAGER_LOCKINGMODE_EXCLUSIVE. If the parameter is not _QUERY, then
|
| -** the locking-mode is set to the value specified.
|
| -**
|
| -** The returned value is either PAGER_LOCKINGMODE_NORMAL or
|
| -** PAGER_LOCKINGMODE_EXCLUSIVE, indicating the current (possibly updated)
|
| -** locking-mode.
|
| -*/
|
| -int sqlite3PagerLockingMode(Pager *pPager, int eMode){
|
| - assert( eMode==PAGER_LOCKINGMODE_QUERY
|
| - || eMode==PAGER_LOCKINGMODE_NORMAL
|
| - || eMode==PAGER_LOCKINGMODE_EXCLUSIVE );
|
| - assert( PAGER_LOCKINGMODE_QUERY<0 );
|
| - assert( PAGER_LOCKINGMODE_NORMAL>=0 && PAGER_LOCKINGMODE_EXCLUSIVE>=0 );
|
| - if( eMode>=0 && !pPager->tempFile ){
|
| - pPager->exclusiveMode = (u8)eMode;
|
| - }
|
| - return (int)pPager->exclusiveMode;
|
| -}
|
| -
|
| -/*
|
| -** Get/set the journal-mode for this pager. Parameter eMode must be one of:
|
| -**
|
| -** PAGER_JOURNALMODE_QUERY
|
| -** PAGER_JOURNALMODE_DELETE
|
| -** PAGER_JOURNALMODE_TRUNCATE
|
| -** PAGER_JOURNALMODE_PERSIST
|
| -** PAGER_JOURNALMODE_OFF
|
| -** PAGER_JOURNALMODE_MEMORY
|
| -**
|
| -** If the parameter is not _QUERY, then the journal_mode is set to the
|
| -** value specified if the change is allowed. The change is disallowed
|
| -** for the following reasons:
|
| -**
|
| -** * An in-memory database can only have its journal_mode set to _OFF
|
| -** or _MEMORY.
|
| -**
|
| -** * The journal mode may not be changed while a transaction is active.
|
| -**
|
| -** The returned indicate the current (possibly updated) journal-mode.
|
| -*/
|
| -int sqlite3PagerJournalMode(Pager *pPager, int eMode){
|
| - assert( eMode==PAGER_JOURNALMODE_QUERY
|
| - || eMode==PAGER_JOURNALMODE_DELETE
|
| - || eMode==PAGER_JOURNALMODE_TRUNCATE
|
| - || eMode==PAGER_JOURNALMODE_PERSIST
|
| - || eMode==PAGER_JOURNALMODE_OFF
|
| - || eMode==PAGER_JOURNALMODE_MEMORY );
|
| - assert( PAGER_JOURNALMODE_QUERY<0 );
|
| - if( eMode>=0
|
| - && (!MEMDB || eMode==PAGER_JOURNALMODE_MEMORY
|
| - || eMode==PAGER_JOURNALMODE_OFF)
|
| - && !pPager->dbModified
|
| - && (!isOpen(pPager->jfd) || 0==pPager->journalOff)
|
| - ){
|
| - if( isOpen(pPager->jfd) ){
|
| - sqlite3OsClose(pPager->jfd);
|
| - }
|
| - pPager->journalMode = (u8)eMode;
|
| - }
|
| - return (int)pPager->journalMode;
|
| -}
|
| -
|
| -/*
|
| -** Get/set the size-limit used for persistent journal files.
|
| -**
|
| -** Setting the size limit to -1 means no limit is enforced.
|
| -** An attempt to set a limit smaller than -1 is a no-op.
|
| -*/
|
| -i64 sqlite3PagerJournalSizeLimit(Pager *pPager, i64 iLimit){
|
| - if( iLimit>=-1 ){
|
| - pPager->journalSizeLimit = iLimit;
|
| - }
|
| - return pPager->journalSizeLimit;
|
| -}
|
| -
|
| -/*
|
| -** Return a pointer to the pPager->pBackup variable. The backup module
|
| -** in backup.c maintains the content of this variable. This module
|
| -** uses it opaquely as an argument to sqlite3BackupRestart() and
|
| -** sqlite3BackupUpdate() only.
|
| -*/
|
| -sqlite3_backup **sqlite3PagerBackupPtr(Pager *pPager){
|
| - return &pPager->pBackup;
|
| -}
|
| -
|
| -#endif /* SQLITE_OMIT_DISKIO */
|
|
|
Chromium Code Reviews
Issue 3108030:
Move bundled copy of sqlite one level deeper to better separate it... (Closed)
Base URL: svn://svn.chromium.org/chrome/trunk/src/