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Ensure that "PRAGMA wal_checkpoint = TRUNCATE|FULL|RESTART" block on other connections and truncate the database file as required even if the entire wal file has already been checkpointed.

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FossilOrigin-Name: 53429689d4fcf472edbc89cc50b5e69ba3270634
This commit is contained in:
dan
2015-01-29 19:12:12 +00:00
parent 6267920b09
commit 976b003344
5 changed files with 185 additions and 100 deletions
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183
src/wal.c
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@@ -1694,7 +1694,7 @@ static int walCheckpoint(
int sync_flags, /* Flags for OsSync() (or 0) */
u8 *zBuf /* Temporary buffer to use */
){
int rc; /* Return code */
int rc = SQLITE_OK; /* Return code */
int szPage; /* Database page-size */
WalIterator *pIter = 0; /* Wal iterator context */
u32 iDbpage = 0; /* Next database page to write */
@@ -1708,104 +1708,107 @@ static int walCheckpoint(
testcase( szPage<=32768 );
testcase( szPage>=65536 );
pInfo = walCkptInfo(pWal);
if( pInfo->nBackfill>=pWal->hdr.mxFrame ) return SQLITE_OK;
if( pInfo->nBackfill<pWal->hdr.mxFrame ){
/* Allocate the iterator */
rc = walIteratorInit(pWal, &pIter);
if( rc!=SQLITE_OK ){
return rc;
}
assert( pIter );
/* EVIDENCE-OF: R-62920-47450 The busy-handler callback is never invoked
** in the SQLITE_CHECKPOINT_PASSIVE mode. */
assert( eMode!=SQLITE_CHECKPOINT_PASSIVE || xBusy==0 );
/* Compute in mxSafeFrame the index of the last frame of the WAL that is
** safe to write into the database. Frames beyond mxSafeFrame might
** overwrite database pages that are in use by active readers and thus
** cannot be backfilled from the WAL.
*/
mxSafeFrame = pWal->hdr.mxFrame;
mxPage = pWal->hdr.nPage;
for(i=1; i<WAL_NREADER; i++){
u32 y = pInfo->aReadMark[i];
if( mxSafeFrame>y ){
assert( y<=pWal->hdr.mxFrame );
rc = walBusyLock(pWal, xBusy, pBusyArg, WAL_READ_LOCK(i), 1);
if( rc==SQLITE_OK ){
pInfo->aReadMark[i] = (i==1 ? mxSafeFrame : READMARK_NOT_USED);
walUnlockExclusive(pWal, WAL_READ_LOCK(i), 1);
}else if( rc==SQLITE_BUSY ){
mxSafeFrame = y;
xBusy = 0;
}else{
goto walcheckpoint_out;
}
/* Allocate the iterator */
rc = walIteratorInit(pWal, &pIter);
if( rc!=SQLITE_OK ){
return rc;
}
}
assert( pIter );
if( pInfo->nBackfill<mxSafeFrame
&& (rc = walBusyLock(pWal, xBusy, pBusyArg, WAL_READ_LOCK(0), 1))==SQLITE_OK
){
i64 nSize; /* Current size of database file */
u32 nBackfill = pInfo->nBackfill;
/* EVIDENCE-OF: R-62920-47450 The busy-handler callback is never invoked
** in the SQLITE_CHECKPOINT_PASSIVE mode. */
assert( eMode!=SQLITE_CHECKPOINT_PASSIVE || xBusy==0 );
/* Sync the WAL to disk */
if( sync_flags ){
rc = sqlite3OsSync(pWal->pWalFd, sync_flags);
}
/* If the database may grow as a result of this checkpoint, hint
** about the eventual size of the db file to the VFS layer.
/* Compute in mxSafeFrame the index of the last frame of the WAL that is
** safe to write into the database. Frames beyond mxSafeFrame might
** overwrite database pages that are in use by active readers and thus
** cannot be backfilled from the WAL.
*/
if( rc==SQLITE_OK ){
i64 nReq = ((i64)mxPage * szPage);
rc = sqlite3OsFileSize(pWal->pDbFd, &nSize);
if( rc==SQLITE_OK && nSize<nReq ){
sqlite3OsFileControlHint(pWal->pDbFd, SQLITE_FCNTL_SIZE_HINT, &nReq);
}
}
/* Iterate through the contents of the WAL, copying data to the db file. */
while( rc==SQLITE_OK && 0==walIteratorNext(pIter, &iDbpage, &iFrame) ){
i64 iOffset;
assert( walFramePgno(pWal, iFrame)==iDbpage );
if( iFrame<=nBackfill || iFrame>mxSafeFrame || iDbpage>mxPage ) continue;
iOffset = walFrameOffset(iFrame, szPage) + WAL_FRAME_HDRSIZE;
/* testcase( IS_BIG_INT(iOffset) ); // requires a 4GiB WAL file */
rc = sqlite3OsRead(pWal->pWalFd, zBuf, szPage, iOffset);
if( rc!=SQLITE_OK ) break;
iOffset = (iDbpage-1)*(i64)szPage;
testcase( IS_BIG_INT(iOffset) );
rc = sqlite3OsWrite(pWal->pDbFd, zBuf, szPage, iOffset);
if( rc!=SQLITE_OK ) break;
}
/* If work was actually accomplished... */
if( rc==SQLITE_OK ){
if( mxSafeFrame==walIndexHdr(pWal)->mxFrame ){
i64 szDb = pWal->hdr.nPage*(i64)szPage;
testcase( IS_BIG_INT(szDb) );
rc = sqlite3OsTruncate(pWal->pDbFd, szDb);
if( rc==SQLITE_OK && sync_flags ){
rc = sqlite3OsSync(pWal->pDbFd, sync_flags);
mxSafeFrame = pWal->hdr.mxFrame;
mxPage = pWal->hdr.nPage;
for(i=1; i<WAL_NREADER; i++){
u32 y = pInfo->aReadMark[i];
if( mxSafeFrame>y ){
assert( y<=pWal->hdr.mxFrame );
rc = walBusyLock(pWal, xBusy, pBusyArg, WAL_READ_LOCK(i), 1);
if( rc==SQLITE_OK ){
pInfo->aReadMark[i] = (i==1 ? mxSafeFrame : READMARK_NOT_USED);
walUnlockExclusive(pWal, WAL_READ_LOCK(i), 1);
}else if( rc==SQLITE_BUSY ){
mxSafeFrame = y;
xBusy = 0;
}else{
goto walcheckpoint_out;
}
}
if( rc==SQLITE_OK ){
pInfo->nBackfill = mxSafeFrame;
}
}
/* Release the reader lock held while backfilling */
walUnlockExclusive(pWal, WAL_READ_LOCK(0), 1);
}
if( pInfo->nBackfill<mxSafeFrame
&& (rc = walBusyLock(pWal, xBusy, pBusyArg, WAL_READ_LOCK(0),1))==SQLITE_OK
){
i64 nSize; /* Current size of database file */
u32 nBackfill = pInfo->nBackfill;
if( rc==SQLITE_BUSY ){
/* Reset the return code so as not to report a checkpoint failure
** just because there are active readers. */
rc = SQLITE_OK;
/* Sync the WAL to disk */
if( sync_flags ){
rc = sqlite3OsSync(pWal->pWalFd, sync_flags);
}
/* If the database may grow as a result of this checkpoint, hint
** about the eventual size of the db file to the VFS layer.
*/
if( rc==SQLITE_OK ){
i64 nReq = ((i64)mxPage * szPage);
rc = sqlite3OsFileSize(pWal->pDbFd, &nSize);
if( rc==SQLITE_OK && nSize<nReq ){
sqlite3OsFileControlHint(pWal->pDbFd, SQLITE_FCNTL_SIZE_HINT, &nReq);
}
}
/* Iterate through the contents of the WAL, copying data to the db file */
while( rc==SQLITE_OK && 0==walIteratorNext(pIter, &iDbpage, &iFrame) ){
i64 iOffset;
assert( walFramePgno(pWal, iFrame)==iDbpage );
if( iFrame<=nBackfill || iFrame>mxSafeFrame || iDbpage>mxPage ){
continue;
}
iOffset = walFrameOffset(iFrame, szPage) + WAL_FRAME_HDRSIZE;
/* testcase( IS_BIG_INT(iOffset) ); // requires a 4GiB WAL file */
rc = sqlite3OsRead(pWal->pWalFd, zBuf, szPage, iOffset);
if( rc!=SQLITE_OK ) break;
iOffset = (iDbpage-1)*(i64)szPage;
testcase( IS_BIG_INT(iOffset) );
rc = sqlite3OsWrite(pWal->pDbFd, zBuf, szPage, iOffset);
if( rc!=SQLITE_OK ) break;
}
/* If work was actually accomplished... */
if( rc==SQLITE_OK ){
if( mxSafeFrame==walIndexHdr(pWal)->mxFrame ){
i64 szDb = pWal->hdr.nPage*(i64)szPage;
testcase( IS_BIG_INT(szDb) );
rc = sqlite3OsTruncate(pWal->pDbFd, szDb);
if( rc==SQLITE_OK && sync_flags ){
rc = sqlite3OsSync(pWal->pDbFd, sync_flags);
}
}
if( rc==SQLITE_OK ){
pInfo->nBackfill = mxSafeFrame;
}
}
/* Release the reader lock held while backfilling */
walUnlockExclusive(pWal, WAL_READ_LOCK(0), 1);
}
if( rc==SQLITE_BUSY ){
/* Reset the return code so as not to report a checkpoint failure
** just because there are active readers. */
rc = SQLITE_OK;
}
}
/* If this is an SQLITE_CHECKPOINT_RESTART or TRUNCATE operation, and the
@@ -1820,7 +1823,7 @@ static int walCheckpoint(
}else if( eMode>=SQLITE_CHECKPOINT_RESTART ){
u32 salt1;
sqlite3_randomness(4, &salt1);
assert( mxSafeFrame==pWal->hdr.mxFrame );
assert( pInfo->nBackfill==pWal->hdr.mxFrame );
rc = walBusyLock(pWal, xBusy, pBusyArg, WAL_READ_LOCK(1), WAL_NREADER-1);
if( rc==SQLITE_OK ){
if( eMode==SQLITE_CHECKPOINT_TRUNCATE ){