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Zero the checkpoint header as the last step of successful WAL recovery. Avoid an unnecessary lock/unlock in WalBeginReadTransaction.

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FossilOrigin-Name: db3509c55dfe288650b803622e3a0828c6e59aea
This commit is contained in:
dan
2010-05-31 16:17:54 +00:00
parent 20e1f08e0b
commit 3dee6da994
3 changed files with 17 additions and 21 deletions
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12
src/wal.c
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@ -264,7 +264,7 @@ struct WalIndexHdr {
u32 iChange; /* Counter incremented each transaction */
u16 bigEndCksum; /* True if checksums in WAL are big-endian */
u16 szPage; /* Database page size in bytes */
u32 mxFrame; /* Index of last valid frame in the WAL */
u32 mxFrame; /* Index of last valid frame in the WAL */
u32 nPage; /* Size of database in pages */
u32 aFrameCksum[2]; /* Checksum of last frame in log */
u32 aSalt[2]; /* Two salt values copied from WAL header */
@ -1050,6 +1050,12 @@ finished:
pWal->hdr.aFrameCksum[0] = aFrameCksum[0];
pWal->hdr.aFrameCksum[1] = aFrameCksum[1];
walIndexWriteHdr(pWal);
/* Zero the checkpoint-header. This is safe because this thread is
** currently holding locks that exclude all other readers, writers and
** checkpointers.
*/
memset((void *)walCkptInfo(pWal), 0, sizeof(WalCkptInfo));
}
recovery_error:
@ -1613,6 +1619,7 @@ static int walIndexReadHdr(Wal *pWal, int *pChanged){
** needs to be reconstructed. So run recovery to do exactly that.
*/
rc = walIndexRecover(pWal);
*pChanged = 1;
}
walUnlockExclusive(pWal, WAL_WRITE_LOCK, 1);
pWal->writeLock = 0;
@ -1752,8 +1759,7 @@ static int walTryBeginRead(Wal *pWal, int *pChanged, int useWal){
for(i=1; i<WAL_NREADER; i++){
rc = walLockExclusive(pWal, WAL_READ_LOCK(i), 1);
if( rc==SQLITE_OK ){
pInfo->aReadMark[i] = pWal->hdr.mxFrame+1;
mxReadMark = pWal->hdr.mxFrame;
mxReadMark = pInfo->aReadMark[i] = pWal->hdr.mxFrame+1;
mxI = i;
walUnlockExclusive(pWal, WAL_READ_LOCK(i), 1);
break;