[sql] Import reference version of SQLite 3.17..

third_party/sqlite/sqlite-src-3170000/src/test_sqllog.c

+/*
+** 2012 November 26
+**
+** 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.
+**
+*************************************************************************
+**
+** OVERVIEW
+**
+**   This file contains experimental code used to record data from live
+**   SQLite applications that may be useful for offline analysis. 
+**   Specifically, this module can be used to capture the following
+**   information:
+**
+**     1) The initial contents of all database files opened by the 
+**        application, and
+**
+**     2) All SQL statements executed by the application.
+**
+**   The captured information can then be used to run (for example)
+**   performance analysis looking for slow queries or to look for
+**   optimization opportunities in either the application or in SQLite
+**   itself.
+**
+** USAGE
+**
+**   To use this module, SQLite must be compiled with the SQLITE_ENABLE_SQLLOG
+**   pre-processor symbol defined and this file linked into the application.
+**   One way to link this file into the application is to append the content
+**   of this file onto the end of the "sqlite3.c" amalgamation and then 
+**   recompile the application as normal except with the addition  of the
+**   -DSQLITE_ENABLE_SQLLOG option.
+**
+**   At runtime, logging is enabled by setting environment variable
+**   SQLITE_SQLLOG_DIR to the name of a directory in which to store logged 
+**   data. The logging directory must already exist.
+**
+**   Usually, if the application opens the same database file more than once
+**   (either by attaching it or by using more than one database handle), only
+**   a single copy is made. This behavior may be overridden (so that a 
+**   separate copy is taken each time the database file is opened or attached)
+**   by setting the environment variable SQLITE_SQLLOG_REUSE_FILES to 0.
+**
+**   If the environment variable SQLITE_SQLLOG_CONDITIONAL is defined, then
+**   logging is only done for database connections if a file named
+**   "<database>-sqllog" exists in the same directly as the main database
+**   file when it is first opened ("<database>" is replaced by the actual 
+**   name of the main database file).
+**
+** OUTPUT:
+**
+**   The SQLITE_SQLLOG_DIR is populated with three types of files:
+**
+**      sqllog_N.db   - Copies of database files. N may be any integer.
+**
+**      sqllog_N.sql  - A list of SQL statements executed by a single
+**                      connection. N may be any integer.
+**
+**      sqllog.idx    - An index mapping from integer N to a database
+**                      file name - indicating the full path of the
+**                      database from which sqllog_N.db was copied.
+**
+** ERROR HANDLING:
+**
+**   This module attempts to make a best effort to continue logging if an
+**   IO or other error is encountered. For example, if a log file cannot 
+**   be opened logs are not collected for that connection, but other
+**   logging proceeds as expected. Errors are logged by calling sqlite3_log().
+*/
+
+#ifndef _SQLITE3_H_
+#include "sqlite3.h"
+#endif
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <assert.h>
+
+#include <sys/types.h>
+#include <unistd.h>
+static int getProcessId(void){
+#if SQLITE_OS_WIN
+  return (int)_getpid();
+#else
+  return (int)getpid();
+#endif
+}
+
+/* Names of environment variables to be used */
+#define ENVIRONMENT_VARIABLE1_NAME "SQLITE_SQLLOG_DIR"
+#define ENVIRONMENT_VARIABLE2_NAME "SQLITE_SQLLOG_REUSE_FILES"
+#define ENVIRONMENT_VARIABLE3_NAME "SQLITE_SQLLOG_CONDITIONAL"
+
+/* Assume that all database and database file names are shorted than this. */
+#define SQLLOG_NAMESZ 512
+
+/* Maximum number of simultaneous database connections the process may
+** open (if any more are opened an error is logged using sqlite3_log()
+** and processing is halted).
+*/
+#define MAX_CONNECTIONS 256
+
+/* There is one instance of this object for each SQLite database connection
+** that is being logged.
+*/
+struct SLConn {
+  int isErr;                      /* True if an error has occurred */
+  sqlite3 *db;                    /* Connection handle */
+  int iLog;                       /* First integer value used in file names */
+  FILE *fd;                       /* File descriptor for log file */
+};
+
+/* This object is a singleton that keeps track of all data loggers.
+*/
+static struct SLGlobal {
+  /* Protected by MUTEX_STATIC_MASTER */
+  sqlite3_mutex *mutex;           /* Recursive mutex */
+  int nConn;                      /* Size of aConn[] array */
+
+  /* Protected by SLGlobal.mutex */
+  int bConditional;               /* Only trace if *-sqllog file is present */
+  int bReuse;                     /* True to avoid extra copies of db files */
+  char zPrefix[SQLLOG_NAMESZ];    /* Prefix for all created files */
+  char zIdx[SQLLOG_NAMESZ];       /* Full path to *.idx file */
+  int iNextLog;                   /* Used to allocate file names */
+  int iNextDb;                    /* Used to allocate database file names */
+  int bRec;                       /* True if testSqllog() is called rec. */
+  int iClock;                     /* Clock value */
+  struct SLConn aConn[MAX_CONNECTIONS];
+} sqllogglobal;
+
+/*
+** Return true if c is an ASCII whitespace character.
+*/
+static int sqllog_isspace(char c){
+  return (c==' ' || c=='\t' || c=='\n' || c=='\v' || c=='\f' || c=='\r');
+}
+
+/*
+** The first argument points to a nul-terminated string containing an SQL
+** command. Before returning, this function sets *pz to point to the start
+** of the first token in this command, and *pn to the number of bytes in 
+** the token. This is used to check if the SQL command is an "ATTACH" or 
+** not.
+*/
+static void sqllogTokenize(const char *z, const char **pz, int *pn){
+  const char *p = z;
+  int n;
+
+  /* Skip past any whitespace */
+  while( sqllog_isspace(*p) ){
+    p++;
+  }
+
+  /* Figure out how long the first token is */
+  *pz = p;
+  n = 0;
+  while( (p[n]>='a' && p[n]<='z') || (p[n]>='A' && p[n]<='Z') ) n++;
+  *pn = n;
+}
+
+/*
+** Check if the logs directory already contains a copy of database file 
+** zFile. If so, return a pointer to the full path of the copy. Otherwise,
+** return NULL.
+**
+** If a non-NULL value is returned, then the caller must arrange to 
+** eventually free it using sqlite3_free().
+*/
+static char *sqllogFindFile(const char *zFile){
+  char *zRet = 0;
+  FILE *fd = 0;
+
+  /* Open the index file for reading */
+  fd = fopen(sqllogglobal.zIdx, "r");
+  if( fd==0 ){
+    sqlite3_log(SQLITE_IOERR, "sqllogFindFile(): error in fopen()");
+    return 0;
+  }
+
+  /* Loop through each entry in the index file. If zFile is not NULL and the
+  ** entry is a match, then set zRet to point to the filename of the existing
+  ** copy and break out of the loop.  */
+  while( feof(fd)==0 ){
+    char zLine[SQLLOG_NAMESZ*2+5];
+    if( fgets(zLine, sizeof(zLine), fd) ){
+      int n;
+      char *z;
+
+      zLine[sizeof(zLine)-1] = '\0';
+      z = zLine;
+      while( *z>='0' && *z<='9' ) z++;
+      while( *z==' ' ) z++;
+
+      n = strlen(z);
+      while( n>0 && sqllog_isspace(z[n-1]) ) n--;
+
+      if( n==strlen(zFile) && 0==memcmp(zFile, z, n) ){
+        char zBuf[16];
+        memset(zBuf, 0, sizeof(zBuf));
+        z = zLine;
+        while( *z>='0' && *z<='9' ){
+          zBuf[z-zLine] = *z;
+          z++;
+        }
+        zRet = sqlite3_mprintf("%s_%s.db", sqllogglobal.zPrefix, zBuf);
+        break;
+      }
+    }
+  }
+
+  if( ferror(fd) ){
+    sqlite3_log(SQLITE_IOERR, "sqllogFindFile(): error reading index file");
+  }
+
+  fclose(fd);
+  return zRet;
+}
+
+static int sqllogFindAttached(
+  sqlite3 *db,                    /* Database connection */
+  const char *zSearch,            /* Name to search for (or NULL) */
+  char *zName,                    /* OUT: Name of attached database */
+  char *zFile                     /* OUT: Name of attached file */
+){
+  sqlite3_stmt *pStmt;
+  int rc;
+
+  /* The "PRAGMA database_list" command returns a list of databases in the
+  ** order that they were attached. So a newly attached database is 
+  ** described by the last row returned.  */
+  assert( sqllogglobal.bRec==0 );
+  sqllogglobal.bRec = 1;
+  rc = sqlite3_prepare_v2(db, "PRAGMA database_list", -1, &pStmt, 0);
+  if( rc==SQLITE_OK ){
+    while( SQLITE_ROW==sqlite3_step(pStmt) ){
+      const char *zVal1; int nVal1;
+      const char *zVal2; int nVal2;
+
+      zVal1 = (const char*)sqlite3_column_text(pStmt, 1);
+      nVal1 = sqlite3_column_bytes(pStmt, 1);
+      if( zName ){
+        memcpy(zName, zVal1, nVal1+1);
+      }
+
+      zVal2 = (const char*)sqlite3_column_text(pStmt, 2);
+      nVal2 = sqlite3_column_bytes(pStmt, 2);
+      memcpy(zFile, zVal2, nVal2+1);
+
+      if( zSearch && strlen(zSearch)==nVal1 
+       && 0==sqlite3_strnicmp(zSearch, zVal1, nVal1)
+      ){
+        break;
+      }
+    }
+    rc = sqlite3_finalize(pStmt);
+  }
+  sqllogglobal.bRec = 0;
+
+  if( rc!=SQLITE_OK ){
+    sqlite3_log(rc, "sqllogFindAttached(): error in \"PRAGMA database_list\"");
+  }
+  return rc;
+}
+
+
+/*
+** Parameter zSearch is the name of a database attached to the database 
+** connection associated with the first argument. This function creates
+** a backup of this database in the logs directory.
+**
+** The name used for the backup file is automatically generated. Call
+** it zFile.
+**
+** If the bLog parameter is true, then a statement of the following form
+** is written to the log file associated with *p:
+**
+**    ATTACH 'zFile' AS 'zName';
+**
+** Otherwise, if bLog is false, a comment is added to the log file:
+**
+**    -- Main database file is 'zFile'
+**
+** The SLGlobal.mutex mutex is always held when this function is called.
+*/
+static void sqllogCopydb(struct SLConn *p, const char *zSearch, int bLog){
+  char zName[SQLLOG_NAMESZ];      /* Attached database name */
+  char zFile[SQLLOG_NAMESZ];      /* Database file name */
+  char *zFree;
+  char *zInit = 0;
+  int rc;
+
+  rc = sqllogFindAttached(p->db, zSearch, zName, zFile);
+  if( rc!=SQLITE_OK ) return;
+
+  if( zFile[0]=='\0' ){
+    zInit = sqlite3_mprintf("");
+  }else{
+    if( sqllogglobal.bReuse ){
+      zInit = sqllogFindFile(zFile);
+    }else{
+      zInit = 0;
+    }
+    if( zInit==0 ){
+      int rc;
+      sqlite3 *copy = 0;
+      int iDb;
+
+      /* Generate a file-name to use for the copy of this database */
+      iDb = sqllogglobal.iNextDb++;
+      zInit = sqlite3_mprintf("%s_%02d.db", sqllogglobal.zPrefix, iDb);
+
+      /* Create the backup */
+      assert( sqllogglobal.bRec==0 );
+      sqllogglobal.bRec = 1;
+      rc = sqlite3_open(zInit, &copy);
+      if( rc==SQLITE_OK ){
+        sqlite3_backup *pBak;
+        sqlite3_exec(copy, "PRAGMA synchronous = 0", 0, 0, 0);
+        pBak = sqlite3_backup_init(copy, "main", p->db, zName);
+        if( pBak ){
+          sqlite3_backup_step(pBak, -1);
+          rc = sqlite3_backup_finish(pBak);
+        }else{
+          rc = sqlite3_errcode(copy);
+        }
+        sqlite3_close(copy);
+      }
+      sqllogglobal.bRec = 0;
+
+      if( rc==SQLITE_OK ){
+        /* Write an entry into the database index file */
+        FILE *fd = fopen(sqllogglobal.zIdx, "a");
+        if( fd ){
+          fprintf(fd, "%d %s\n", iDb, zFile);
+          fclose(fd);
+        }
+      }else{
+        sqlite3_log(rc, "sqllogCopydb(): error backing up database");
+      }
+    }
+  }
+
+  if( bLog ){
+    zFree = sqlite3_mprintf("ATTACH '%q' AS '%q'; -- clock=%d\n", 
+        zInit, zName, sqllogglobal.iClock++
+    );
+  }else{
+    zFree = sqlite3_mprintf("-- Main database is '%q'\n", zInit);
+  }
+  fprintf(p->fd, "%s", zFree);
+  sqlite3_free(zFree);
+
+  sqlite3_free(zInit);
+}
+
+/*
+** If it is not already open, open the log file for connection *p. 
+**
+** The SLGlobal.mutex mutex is always held when this function is called.
+*/
+static void sqllogOpenlog(struct SLConn *p){
+  /* If the log file has not yet been opened, open it now. */
+  if( p->fd==0 ){
+    char *zLog;
+
+    /* If it is still NULL, have global.zPrefix point to a copy of 
+    ** environment variable $ENVIRONMENT_VARIABLE1_NAME.  */
+    if( sqllogglobal.zPrefix[0]==0 ){
+      FILE *fd;
+      char *zVar = getenv(ENVIRONMENT_VARIABLE1_NAME);
+      if( zVar==0 || strlen(zVar)+10>=(sizeof(sqllogglobal.zPrefix)) ) return;
+      sqlite3_snprintf(sizeof(sqllogglobal.zPrefix), sqllogglobal.zPrefix,
+                        "%s/sqllog_%05d", zVar, getProcessId());
+      sqlite3_snprintf(sizeof(sqllogglobal.zIdx), sqllogglobal.zIdx,
+                        "%s.idx", sqllogglobal.zPrefix);
+      if( getenv(ENVIRONMENT_VARIABLE2_NAME) ){
+        sqllogglobal.bReuse = atoi(getenv(ENVIRONMENT_VARIABLE2_NAME));
+      }
+      fd = fopen(sqllogglobal.zIdx, "w");
+      if( fd ) fclose(fd);
+    }
+
+    /* Open the log file */
+    zLog = sqlite3_mprintf("%s_%05d.sql", sqllogglobal.zPrefix, p->iLog);
+    p->fd = fopen(zLog, "w");
+    sqlite3_free(zLog);
+    if( p->fd==0 ){
+      sqlite3_log(SQLITE_IOERR, "sqllogOpenlog(): Failed to open log file");
+    }
+  }
+}
+
+/*
+** This function is called if the SQLLOG callback is invoked to report
+** execution of an SQL statement. Parameter p is the connection the statement
+** was executed by and parameter zSql is the text of the statement itself.
+*/
+static void testSqllogStmt(struct SLConn *p, const char *zSql){
+  const char *zFirst;             /* Pointer to first token in zSql */
+  int nFirst;                     /* Size of token zFirst in bytes */
+
+  sqllogTokenize(zSql, &zFirst, &nFirst);
+  if( nFirst!=6 || 0!=sqlite3_strnicmp("ATTACH", zFirst, 6) ){
+    /* Not an ATTACH statement. Write this directly to the log. */
+    fprintf(p->fd, "%s; -- clock=%d\n", zSql, sqllogglobal.iClock++);
+  }else{
+    /* This is an ATTACH statement. Copy the database. */
+    sqllogCopydb(p, 0, 1);
+  }
+}
+
+/*
+** The database handle passed as the only argument has just been opened.
+** Return true if this module should log initial databases and SQL 
+** statements for this connection, or false otherwise.
+**
+** If an error occurs, sqlite3_log() is invoked to report it to the user
+** and zero returned.
+*/
+static int sqllogTraceDb(sqlite3 *db){
+  int bRet = 1;
+  if( sqllogglobal.bConditional ){
+    char zFile[SQLLOG_NAMESZ];      /* Attached database name */
+    int rc = sqllogFindAttached(db, "main", 0, zFile);
+    if( rc==SQLITE_OK ){
+      int nFile = strlen(zFile);
+      if( (SQLLOG_NAMESZ-nFile)<8 ){
+        sqlite3_log(SQLITE_IOERR, 
+            "sqllogTraceDb(): database name too long (%d bytes)", nFile
+        );
+        bRet = 0;
+      }else{
+        memcpy(&zFile[nFile], "-sqllog", 8);
+        bRet = !access(zFile, F_OK);
+      }
+    }
+  }
+  return bRet;
+}
+
+/*
+** The SQLITE_CONFIG_SQLLOG callback registered by sqlite3_init_sqllog().
+**
+** The eType parameter has the following values:
+**
+**    0:  Opening a new database connection.  zSql is the name of the
+**        file being opened.  db is a pointer to the newly created database
+**        connection.
+**
+**    1:  An SQL statement has run to completion.  zSql is the text of the
+**        SQL statement with all parameters expanded to their actual values.
+**
+**    2:  Closing a database connection.  zSql is NULL.  The db pointer to
+**        the database connection being closed has already been shut down
+**        and cannot be used for any further SQL.
+**
+** The pCtx parameter is a copy of the pointer that was originally passed
+** into the sqlite3_config(SQLITE_CONFIG_SQLLOG) statement.  In this
+** particular implementation, pCtx is always a pointer to the 
+** sqllogglobal global variable define above.
+*/
+static void testSqllog(void *pCtx, sqlite3 *db, const char *zSql, int eType){
+  struct SLConn *p = 0;
+  sqlite3_mutex *master = sqlite3_mutex_alloc(SQLITE_MUTEX_STATIC_MASTER);
+
+  assert( eType==0 || eType==1 || eType==2 );
+  assert( (eType==2)==(zSql==0) );
+
+  /* This is a database open command. */
+  if( eType==0 ){
+    sqlite3_mutex_enter(master);
+    if( sqllogglobal.mutex==0 ){
+      sqllogglobal.mutex = sqlite3_mutex_alloc(SQLITE_MUTEX_RECURSIVE);
+    }
+    sqlite3_mutex_leave(master);
+
+    sqlite3_mutex_enter(sqllogglobal.mutex);
+    if( sqllogglobal.bRec==0 && sqllogTraceDb(db) ){
+
+      sqlite3_mutex_enter(master);
+      p = &sqllogglobal.aConn[sqllogglobal.nConn++];
+      p->fd = 0;
+      p->db = db;
+      p->iLog = sqllogglobal.iNextLog++;
+      sqlite3_mutex_leave(master);
+
+      /* Open the log and take a copy of the main database file */
+      sqllogOpenlog(p);
+      if( p->fd ) sqllogCopydb(p, "main", 0);
+    }
+    sqlite3_mutex_leave(sqllogglobal.mutex);
+  }
+
+  else{
+
+    int i;
+    for(i=0; i<sqllogglobal.nConn; i++){
+      p = &sqllogglobal.aConn[i];
+      if( p->db==db ) break;
+    }
+
+    /* A database handle close command */
+    if( eType==2 ){
+      sqlite3_mutex_enter(master);
+      if( i<sqllogglobal.nConn ){
+        if( p->fd ) fclose(p->fd);
+        p->db = 0;
+        p->fd = 0;
+        sqllogglobal.nConn--;
+      }
+
+      if( sqllogglobal.nConn==0 ){
+        sqlite3_mutex_free(sqllogglobal.mutex);
+        sqllogglobal.mutex = 0;
+      }else if( i<sqllogglobal.nConn ){
+        int nShift = &sqllogglobal.aConn[sqllogglobal.nConn] - p;
+        if( nShift>0 ){
+          memmove(p, &p[1], nShift*sizeof(struct SLConn));
+        }
+      }
+      sqlite3_mutex_leave(master);
+
+    /* An ordinary SQL command. */
+    }else if( i<sqllogglobal.nConn && p->fd ){
+      sqlite3_mutex_enter(sqllogglobal.mutex);
+      if( sqllogglobal.bRec==0 ){
+        testSqllogStmt(p, zSql);
+      }
+      sqlite3_mutex_leave(sqllogglobal.mutex);
+    }
+  }
+}
+
+/*
+** This function is called either before sqlite3_initialized() or by it.
+** It checks if the SQLITE_SQLLOG_DIR variable is defined, and if so 
+** registers an SQLITE_CONFIG_SQLLOG callback to record the applications
+** database activity.
+*/
+void sqlite3_init_sqllog(void){
+  if( getenv(ENVIRONMENT_VARIABLE1_NAME) ){
+    if( SQLITE_OK==sqlite3_config(SQLITE_CONFIG_SQLLOG, testSqllog, 0) ){
+      memset(&sqllogglobal, 0, sizeof(sqllogglobal));
+      sqllogglobal.bReuse = 1;
+      if( getenv(ENVIRONMENT_VARIABLE3_NAME) ){
+        sqllogglobal.bConditional = 1;
+      }
+    }
+  }
+}