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Ensure that there is always at least one aReadMark slot usable by an unprivileged reader while a checkpoint is running. Also, if one or more transactions are recovered from a log file, initialize one of the aReadMark slots to contain mxFrame as part of the recovery process.

FossilOrigin-Name: e4163596339c2166f9c4356ab824fff8bda8d0b0
This commit is contained in:
dan
2012-07-17 14:37:12 +00:00
parent 610b8d8578
commit 5373b76bdc
7 changed files with 172 additions and 16 deletions

View File

@@ -1199,6 +1199,7 @@ finished:
pInfo->nBackfill = 0;
pInfo->aReadMark[0] = 0;
for(i=1; i<WAL_NREADER; i++) pInfo->aReadMark[i] = READMARK_NOT_USED;
if( pWal->hdr.mxFrame ) pInfo->aReadMark[1] = pWal->hdr.mxFrame;
/* If more than one frame was recovered from the log file, report an
** event via sqlite3_log(). This is to help with identifying performance
@@ -1699,7 +1700,7 @@ static int walCheckpoint(
assert( y<=pWal->hdr.mxFrame );
rc = walBusyLock(pWal, xBusy, pBusyArg, WAL_READ_LOCK(i), 1);
if( rc==SQLITE_OK ){
pInfo->aReadMark[i] = READMARK_NOT_USED;
pInfo->aReadMark[i] = (i==1 ? mxSafeFrame : READMARK_NOT_USED);
walUnlockExclusive(pWal, WAL_READ_LOCK(i), 1);
}else if( rc==SQLITE_BUSY ){
mxSafeFrame = y;