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Fix an obscure problem with transactions written in "PRAGMA synchronous=full" mode on systems that do not support POWERSAFE_OVERWRITE causing an xSync() call to be omitted if the last frame written by a transaction is aligned to a sector boundary. This means that if a power failure or OS crash occurs very soon after such a transaction is committed, it may be lost following system recovery.

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FossilOrigin-Name: 37de3eab67f12ae1ce5bc8d5e541c64fc6b1fd80
This commit is contained in:
dan
2016-05-24 16:20:51 +00:00
parent abecc0b883
commit fe912510ea
5 changed files with 116 additions and 11 deletions
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7
src/wal.c
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@@ -3109,16 +3109,21 @@ int sqlite3WalFrames(
** past the sector boundary is written after the sync.
*/
if( isCommit && (sync_flags & WAL_SYNC_TRANSACTIONS)!=0 ){
int bSync = 1;
if( pWal->padToSectorBoundary ){
int sectorSize = sqlite3SectorSize(pWal->pWalFd);
w.iSyncPoint = ((iOffset+sectorSize-1)/sectorSize)*sectorSize;
bSync = (w.iSyncPoint==iOffset);
testcase( bSync );
while( iOffset<w.iSyncPoint ){
rc = walWriteOneFrame(&w, pLast, nTruncate, iOffset);
if( rc ) return rc;
iOffset += szFrame;
nExtra++;
}
}else{
}
if( bSync ){
assert( rc==SQLITE_OK );
rc = sqlite3OsSync(w.pFd, sync_flags & SQLITE_SYNC_MASK);
}
}