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Further reduction in divergence from trunk.

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FossilOrigin-Name: e4406a6e2660f1f42614d0034d024cc206109ac71e9f8b289aeed2eba20be8e9
This commit is contained in:
drh
2024-12-16 18:13:47 +00:00
parent 6b716403f9
commit 5cf971bdc7
3 changed files with 16 additions and 17 deletions
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19
src/wal.c
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@@ -3746,15 +3746,16 @@ static int walTryBeginRead(Wal *pWal, int *pChanged, int useWal, int *pCnt){
pWal->readLock = eLock;
}
assert( pWal->minFrame==0 && walFramePage(pWal->minFrame)==0 );
}else{
}else
{
u32 mxReadMark; /* Largest aReadMark[] value */
int mxI; /* Index of largest aReadMark[] value */
int i; /* Loop counter */
u32 mxFrame; /* Wal frame to lock to */
if( !useWal && pInfo->nBackfill==pWal->hdr.mxFrame
#ifdef SQLITE_ENABLE_SNAPSHOT
#ifdef SQLITE_ENABLE_SNAPSHOT
&& ((pWal->bGetSnapshot==0 && pWal->pSnapshot==0) || pWal->hdr.mxFrame==0)
#endif
#endif
){
/* The WAL has been completely backfilled (or it is empty).
** and can be safely ignored.
@@ -3770,7 +3771,7 @@ static int walTryBeginRead(Wal *pWal, int *pChanged, int useWal, int *pCnt){
** snapshot. Since holding READ_LOCK(0) prevents a checkpoint from
** happening, this is usually correct.
**
** However, if frames have been appended to the log (or if the log
** However, if frames have been appended to the log (or if the log
** is wrapped and written for that matter) before the READ_LOCK(0)
** is obtained, that is not necessarily true. A checkpointer may
** have started to backfill the appended frames but crashed before
@@ -3794,11 +3795,11 @@ static int walTryBeginRead(Wal *pWal, int *pChanged, int useWal, int *pCnt){
mxReadMark = 0;
mxI = 0;
mxFrame = pWal->hdr.mxFrame;
#ifdef SQLITE_ENABLE_SNAPSHOT
#ifdef SQLITE_ENABLE_SNAPSHOT
if( pWal->pSnapshot && pWal->pSnapshot->mxFrame<mxFrame ){
mxFrame = pWal->pSnapshot->mxFrame;
}
#endif
#endif
for(i=1; i<WAL_NREADER; i++){
u32 thisMark = AtomicLoad(pInfo->aReadMark+i); SEH_INJECT_FAULT;
if( mxReadMark<=thisMark && thisMark<=mxFrame ){
@@ -3841,7 +3842,6 @@ static int walTryBeginRead(Wal *pWal, int *pChanged, int useWal, int *pCnt){
#endif
assert((rc&0xFF)!=SQLITE_BUSY||rc==SQLITE_BUSY||rc==SQLITE_BUSY_TIMEOUT);
return (rc&0xFF)==SQLITE_BUSY ? WAL_RETRY : rc;
}
/* Now that the read-lock has been obtained, check that neither the
** value in the aReadMark[] array or the contents of the wal-index
@@ -3863,9 +3863,9 @@ static int walTryBeginRead(Wal *pWal, int *pChanged, int useWal, int *pCnt){
** to read any frames earlier than minFrame from the wal file - they
** can be safely read directly from the database file.
**
** Because a ShmBarrier() call is made between taking the copy of
** Because a ShmBarrier() call is made between taking the copy of
** nBackfill and checking that the wal-header in shared-memory still
** matches the one cached in pWal->hdr, it is guaranteed that the
** matches the one cached in pWal->hdr, it is guaranteed that the
** checkpointer that set nBackfill was not working with a wal-index
** header newer than that cached in pWal->hdr. If it were, that could
** cause a problem. The checkpointer could omit to checkpoint
@@ -4671,7 +4671,6 @@ static int walRestartLog(Wal *pWal){
testcase( rc==SQLITE_PROTOCOL );
testcase( rc==SQLITE_OK );
}
return rc;
}