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Overview
| Comment: | All WAL frame overwrites even if there are active savepoints. This is safe because a ROLLBACK TO will cause all reverted pages to be rewritten to the WAL file prior to COMMIT. |
|---|---|
| Downloads: | Tarball | ZIP archive | SQL archive |
| Timelines: | family | ancestors | descendants | both | wal-overwrite-frames |
| Files: | files | file ages | folders |
| SHA1: |
99b31a6b491c1c51227f478d3713b020 |
| User & Date: | drh 2016-01-09 23:55:47 |
Context
|
2016-01-11
| ||
| 00:52 | Improved testability. (check-in: e83d3a2a user: drh tags: wal-overwrite-frames) | |
|
2016-01-09
| ||
| 23:55 | All WAL frame overwrites even if there are active savepoints. This is safe because a ROLLBACK TO will cause all reverted pages to be rewritten to the WAL file prior to COMMIT. (check-in: 99b31a6b user: drh tags: wal-overwrite-frames) | |
| 18:57 | If it is known that checksums will be recalculated on transaction commit, skip calculating checksums when appending frames to the wal file. When recalculating checksums, recalculate them starting with the first overwritten frame - not the first frame in the transaction. (check-in: 16b34f25 user: dan tags: wal-overwrite-frames) | |
Changes
Changes to src/pager.c.
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pPager->pWal = 0;
pagerFixMaplimit(pPager);
}
}
return rc;
}
/*
** Return the number of open savepoints.
**/
int sqlite3PagerSavepointCount(Pager *pPager){
return pPager->nSavepoint;
}
#ifdef SQLITE_ENABLE_SNAPSHOT
/*
** If this is a WAL database, obtain a snapshot handle for the snapshot
** currently open. Otherwise, return an error.
*/
int sqlite3PagerSnapshotGet(Pager *pPager, sqlite3_snapshot **ppSnapshot){
int rc = SQLITE_ERROR;
|
< < < < < < < |
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pPager->pWal = 0;
pagerFixMaplimit(pPager);
}
}
return rc;
}
#ifdef SQLITE_ENABLE_SNAPSHOT
/*
** If this is a WAL database, obtain a snapshot handle for the snapshot
** currently open. Otherwise, return an error.
*/
int sqlite3PagerSnapshotGet(Pager *pPager, sqlite3_snapshot **ppSnapshot){
int rc = SQLITE_ERROR;
|
Changes to src/pager.h.
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#ifndef SQLITE_OMIT_WAL
int sqlite3PagerCheckpoint(Pager *pPager, int, int*, int*);
int sqlite3PagerWalSupported(Pager *pPager);
int sqlite3PagerWalCallback(Pager *pPager);
int sqlite3PagerOpenWal(Pager *pPager, int *pisOpen);
int sqlite3PagerCloseWal(Pager *pPager);
int sqlite3PagerSavepointCount(Pager *pPager);
# ifdef SQLITE_ENABLE_SNAPSHOT
int sqlite3PagerSnapshotGet(Pager *pPager, sqlite3_snapshot **ppSnapshot);
int sqlite3PagerSnapshotOpen(Pager *pPager, sqlite3_snapshot *pSnapshot);
# endif
#endif
#ifdef SQLITE_ENABLE_ZIPVFS
|
< |
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#ifndef SQLITE_OMIT_WAL int sqlite3PagerCheckpoint(Pager *pPager, int, int*, int*); int sqlite3PagerWalSupported(Pager *pPager); int sqlite3PagerWalCallback(Pager *pPager); int sqlite3PagerOpenWal(Pager *pPager, int *pisOpen); int sqlite3PagerCloseWal(Pager *pPager); # ifdef SQLITE_ENABLE_SNAPSHOT int sqlite3PagerSnapshotGet(Pager *pPager, sqlite3_snapshot **ppSnapshot); int sqlite3PagerSnapshotOpen(Pager *pPager, sqlite3_snapshot *pSnapshot); # endif #endif #ifdef SQLITE_ENABLE_ZIPVFS |
Changes to src/wal.c.
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{ int cnt; for(cnt=0, p=pList; p; p=p->pDirty, cnt++){}
WALTRACE(("WAL%p: frame write begin. %d frames. mxFrame=%d. %s\n",
pWal, cnt, pWal->hdr.mxFrame, isCommit ? "Commit" : "Spill"));
}
#endif
pLive = (WalIndexHdr*)walIndexHdr(pWal);
if( memcmp(&pWal->hdr, (void *)pLive, sizeof(WalIndexHdr))!=0
&& (isCommit || sqlite3PagerSavepointCount(pList->pPager)==0)
){
iFirst = pLive->mxFrame+1;
}
/* See if it is possible to write these frames into the start of the
** log file, instead of appending to it at pWal->hdr.mxFrame.
*/
if( SQLITE_OK!=(rc = walRestartLog(pWal)) ){
|
| < < |
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{ int cnt; for(cnt=0, p=pList; p; p=p->pDirty, cnt++){}
WALTRACE(("WAL%p: frame write begin. %d frames. mxFrame=%d. %s\n",
pWal, cnt, pWal->hdr.mxFrame, isCommit ? "Commit" : "Spill"));
}
#endif
pLive = (WalIndexHdr*)walIndexHdr(pWal);
if( memcmp(&pWal->hdr, (void *)pLive, sizeof(WalIndexHdr))!=0 ){
iFirst = pLive->mxFrame+1;
}
/* See if it is possible to write these frames into the start of the
** log file, instead of appending to it at pWal->hdr.mxFrame.
*/
if( SQLITE_OK!=(rc = walRestartLog(pWal)) ){
|
Changes to test/wal.test.
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list [expr [file size test.db]/1024] [file size test.db-wal]
} [list 37 [wal_file_size 40 1024]]
do_test wal-11.9 {
db close
list [expr [file size test.db]/1024] [log_deleted test.db-wal]
} {37 1}
sqlite3_wal db test.db
set nWal 39
if {[permutation]!="mmap"} {set nWal 37}
ifcapable !mmap {set nWal 37}
do_test wal-11.10 {
execsql {
PRAGMA cache_size = 10;
BEGIN;
INSERT INTO t1 SELECT blob(900) FROM t1; -- 32
SELECT count(*) FROM t1;
}
|
> > > > > | | | > > |
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list [expr [file size test.db]/1024] [file size test.db-wal]
} [list 37 [wal_file_size 40 1024]]
do_test wal-11.9 {
db close
list [expr [file size test.db]/1024] [log_deleted test.db-wal]
} {37 1}
sqlite3_wal db test.db
# After adding the capability of WAL to overwrite prior uncommitted
# frame in the WAL-file with revised content, the size of the WAL file
# following cache-spill is smaller.
#
#set nWal 39
#if {[permutation]!="mmap"} {set nWal 37}
#ifcapable !mmap {set nWal 37}
set nWal 34
do_test wal-11.10 {
execsql {
PRAGMA cache_size = 10;
BEGIN;
INSERT INTO t1 SELECT blob(900) FROM t1; -- 32
SELECT count(*) FROM t1;
}
|