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Overview
| Comment: | Zero the checkpoint header as the last step of successful WAL recovery. Avoid an unnecessary lock/unlock in WalBeginReadTransaction. |
|---|---|
| Downloads: | Tarball | ZIP archive | SQL archive |
| Timelines: | family | ancestors | descendants | both | wal-incr-ckpt |
| Files: | files | file ages | folders |
| SHA1: |
db3509c55dfe288650b803622e3a0828 |
| User & Date: | dan 2010-05-31 16:17:55 |
Context
|
2010-05-31
| ||
| 16:41 | Avoid dropping the checkpoint lock after a recovery run as a precursor to a checkpoint operation. check-in: cc25cfa0 user: dan tags: wal-incr-ckpt | |
| 16:17 | Zero the checkpoint header as the last step of successful WAL recovery. Avoid an unnecessary lock/unlock in WalBeginReadTransaction. check-in: db3509c5 user: dan tags: wal-incr-ckpt | |
| 16:10 | Get the new xShmLock interface design working on os_win.c. check-in: 149a7082 user: drh tags: wal-incr-ckpt | |
Changes
Changes to src/wal.c.
260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 .... 1046 1047 1048 1049 1050 1051 1052 1053 1054 1055 1056 1057 1058 1059 .... 1609 1610 1611 1612 1613 1614 1615 1616 1617 1618 1619 1620 1621 1622 .... 1748 1749 1750 1751 1752 1753 1754 1755 1756 1757 1758 1759 1760 1761 1762 1763 |
** The actual header in the wal-index consists of two copies of this
** object.
*/
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 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 */
u32 aCksum[2]; /* Checksum over all prior fields */
};
/*
................................................................................
if( rc==SQLITE_OK && pWal->hdr.mxFrame==0 ){
rc = walIndexRemap(pWal, walMappingSize(1));
}
if( rc==SQLITE_OK ){
pWal->hdr.aFrameCksum[0] = aFrameCksum[0];
pWal->hdr.aFrameCksum[1] = aFrameCksum[1];
walIndexWriteHdr(pWal);
}
recovery_error:
WALTRACE(("WAL%p: recovery %s\n", pWal, rc ? "failed" : "ok"));
walUnlockExclusive(pWal, WAL_ALL_BUT_WRITE, SQLITE_SHM_NLOCK-1);
return rc;
}
................................................................................
badHdr = walIndexTryHdr(pWal, pChanged);
if( badHdr ){
/* If the wal-index header is still malformed even while holding
** a WRITE lock, it can only mean that the header is corrupted and
** needs to be reconstructed. So run recovery to do exactly that.
*/
rc = walIndexRecover(pWal);
}
walUnlockExclusive(pWal, WAL_WRITE_LOCK, 1);
pWal->writeLock = 0;
}else if( rc!=SQLITE_BUSY ){
return rc;
}
}
................................................................................
}
return WAL_RETRY;
}else{
if( mxReadMark < pWal->hdr.mxFrame ){
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;
mxI = i;
walUnlockExclusive(pWal, WAL_READ_LOCK(i), 1);
break;
}
}
}
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| > > > > > > > | < |
260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 .... 1046 1047 1048 1049 1050 1051 1052 1053 1054 1055 1056 1057 1058 1059 1060 1061 1062 1063 1064 1065 .... 1615 1616 1617 1618 1619 1620 1621 1622 1623 1624 1625 1626 1627 1628 1629 .... 1755 1756 1757 1758 1759 1760 1761 1762 1763 1764 1765 1766 1767 1768 1769 |
** The actual header in the wal-index consists of two copies of this
** object.
*/
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 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 */
u32 aCksum[2]; /* Checksum over all prior fields */
};
/*
................................................................................
if( rc==SQLITE_OK && pWal->hdr.mxFrame==0 ){
rc = walIndexRemap(pWal, walMappingSize(1));
}
if( rc==SQLITE_OK ){
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:
WALTRACE(("WAL%p: recovery %s\n", pWal, rc ? "failed" : "ok"));
walUnlockExclusive(pWal, WAL_ALL_BUT_WRITE, SQLITE_SHM_NLOCK-1);
return rc;
}
................................................................................
badHdr = walIndexTryHdr(pWal, pChanged);
if( badHdr ){
/* If the wal-index header is still malformed even while holding
** a WRITE lock, it can only mean that the header is corrupted and
** 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;
}else if( rc!=SQLITE_BUSY ){
return rc;
}
}
................................................................................
}
return WAL_RETRY;
}else{
if( mxReadMark < pWal->hdr.mxFrame ){
for(i=1; i<WAL_NREADER; i++){
rc = walLockExclusive(pWal, WAL_READ_LOCK(i), 1);
if( rc==SQLITE_OK ){
mxReadMark = pInfo->aReadMark[i] = pWal->hdr.mxFrame+1;
mxI = i;
walUnlockExclusive(pWal, WAL_READ_LOCK(i), 1);
break;
}
}
}
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