| Index: third_party/sqlite/sqlite-src-3080704/doc/pager-invariants.txt
|
| diff --git a/third_party/sqlite/sqlite-src-3080704/doc/pager-invariants.txt b/third_party/sqlite/sqlite-src-3080704/doc/pager-invariants.txt
|
| deleted file mode 100644
|
| index 44444dad54bea03e7a838414f06cb8ed4bcf26b1..0000000000000000000000000000000000000000
|
| --- a/third_party/sqlite/sqlite-src-3080704/doc/pager-invariants.txt
|
| +++ /dev/null
|
| @@ -1,76 +0,0 @@
|
| - *** Throughout this document, a page is deemed to have been synced
|
| - automatically as soon as it is written when PRAGMA synchronous=OFF.
|
| - Otherwise, the page is not synced until the xSync method of the VFS
|
| - is called successfully on the file containing the page.
|
| -
|
| - *** Definition: A page of the database file is said to be "overwriteable" if
|
| - one or more of the following are true about the page:
|
| -
|
| - (a) The original content of the page as it was at the beginning of
|
| - the transaction has been written into the rollback journal and
|
| - synced.
|
| -
|
| - (b) The page was a freelist leaf page at the start of the transaction.
|
| -
|
| - (c) The page number is greater than the largest page that existed in
|
| - the database file at the start of the transaction.
|
| -
|
| - (1) A page of the database file is never overwritten unless one of the
|
| - following are true:
|
| -
|
| - (a) The page and all other pages on the same sector are overwriteable.
|
| -
|
| - (b) The atomic page write optimization is enabled, and the entire
|
| - transaction other than the update of the transaction sequence
|
| - number consists of a single page change.
|
| -
|
| - (2) The content of a page written into the rollback journal exactly matches
|
| - both the content in the database when the rollback journal was written
|
| - and the content in the database at the beginning of the current
|
| - transaction.
|
| -
|
| - (3) Writes to the database file are an integer multiple of the page size
|
| - in length and are aligned to a page boundary.
|
| -
|
| - (4) Reads from the database file are either aligned on a page boundary and
|
| - an integer multiple of the page size in length or are taken from the
|
| - first 100 bytes of the database file.
|
| -
|
| - (5) All writes to the database file are synced prior to the rollback journal
|
| - being deleted, truncated, or zeroed.
|
| -
|
| - (6) If a master journal file is used, then all writes to the database file
|
| - are synced prior to the master journal being deleted.
|
| -
|
| - *** Definition: Two databases (or the same database at two points it time)
|
| - are said to be "logically equivalent" if they give the same answer to
|
| - all queries. Note in particular the content of freelist leaf
|
| - pages can be changed arbitarily without effecting the logical equivalence
|
| - of the database.
|
| -
|
| - (7) At any time, if any subset, including the empty set and the total set,
|
| - of the unsynced changes to a rollback journal are removed and the
|
| - journal is rolled back, the resulting database file will be logical
|
| - equivalent to the database file at the beginning of the transaction.
|
| -
|
| - (8) When a transaction is rolled back, the xTruncate method of the VFS
|
| - is called to restore the database file to the same size it was at
|
| - the beginning of the transaction. (In some VFSes, the xTruncate
|
| - method is a no-op, but that does not change the fact the SQLite will
|
| - invoke it.)
|
| -
|
| - (9) Whenever the database file is modified, at least one bit in the range
|
| - of bytes from 24 through 39 inclusive will be changed prior to releasing
|
| - the EXCLUSIVE lock.
|
| -
|
| -(10) The pattern of bits in bytes 24 through 39 shall not repeat in less
|
| - than one billion transactions.
|
| -
|
| -(11) A database file is well-formed at the beginning and at the conclusion
|
| - of every transaction.
|
| -
|
| -(12) An EXCLUSIVE lock must be held on the database file before making
|
| - any changes to the database file.
|
| -
|
| -(13) A SHARED lock must be held on the database file before reading any
|
| - content out of the database file.
|
|
|