diff options
Diffstat (limited to 'src/backup.c')
| -rw-r--r-- | src/backup.c | 57 |
1 files changed, 46 insertions, 11 deletions
diff --git a/src/backup.c b/src/backup.c index 4881215..252f61c 100644 --- a/src/backup.c +++ b/src/backup.c @@ -212,20 +212,28 @@ static int isFatalError(int rc){ ** page iSrcPg from the source database. Copy this data into the ** destination database. */ -static int backupOnePage(sqlite3_backup *p, Pgno iSrcPg, const u8 *zSrcData){ +static int backupOnePage( + sqlite3_backup *p, /* Backup handle */ + Pgno iSrcPg, /* Source database page to backup */ + const u8 *zSrcData, /* Source database page data */ + int bUpdate /* True for an update, false otherwise */ +){ Pager * const pDestPager = sqlite3BtreePager(p->pDest); const int nSrcPgsz = sqlite3BtreeGetPageSize(p->pSrc); int nDestPgsz = sqlite3BtreeGetPageSize(p->pDest); const int nCopy = MIN(nSrcPgsz, nDestPgsz); const i64 iEnd = (i64)iSrcPg*(i64)nSrcPgsz; #ifdef SQLITE_HAS_CODEC - int nSrcReserve = sqlite3BtreeGetReserve(p->pSrc); + /* Use BtreeGetReserveNoMutex() for the source b-tree, as although it is + ** guaranteed that the shared-mutex is held by this thread, handle + ** p->pSrc may not actually be the owner. */ + int nSrcReserve = sqlite3BtreeGetReserveNoMutex(p->pSrc); int nDestReserve = sqlite3BtreeGetReserve(p->pDest); #endif - int rc = SQLITE_OK; i64 iOff; + assert( sqlite3BtreeGetReserveNoMutex(p->pSrc)>=0 ); assert( p->bDestLocked ); assert( !isFatalError(p->rc) ); assert( iSrcPg!=PENDING_BYTE_PAGE(p->pSrc->pBt) ); @@ -282,6 +290,9 @@ static int backupOnePage(sqlite3_backup *p, Pgno iSrcPg, const u8 *zSrcData){ */ memcpy(zOut, zIn, nCopy); ((u8 *)sqlite3PagerGetExtra(pDestPg))[0] = 0; + if( iOff==0 && bUpdate==0 ){ + sqlite3Put4byte(&zOut[28], sqlite3BtreeLastPage(p->pSrc)); + } } sqlite3PagerUnref(pDestPg); } @@ -386,9 +397,10 @@ int sqlite3_backup_step(sqlite3_backup *p, int nPage){ const Pgno iSrcPg = p->iNext; /* Source page number */ if( iSrcPg!=PENDING_BYTE_PAGE(p->pSrc->pBt) ){ DbPage *pSrcPg; /* Source page object */ - rc = sqlite3PagerGet(pSrcPager, iSrcPg, &pSrcPg); + rc = sqlite3PagerAcquire(pSrcPager, iSrcPg, &pSrcPg, + PAGER_ACQUIRE_READONLY); if( rc==SQLITE_OK ){ - rc = backupOnePage(p, iSrcPg, sqlite3PagerGetData(pSrcPg)); + rc = backupOnePage(p, iSrcPg, sqlite3PagerGetData(pSrcPg), 0); sqlite3PagerUnref(pSrcPg); } } @@ -410,7 +422,13 @@ int sqlite3_backup_step(sqlite3_backup *p, int nPage){ ** same schema version. */ if( rc==SQLITE_DONE ){ - rc = sqlite3BtreeUpdateMeta(p->pDest,1,p->iDestSchema+1); + if( nSrcPage==0 ){ + rc = sqlite3BtreeNewDb(p->pDest); + nSrcPage = 1; + } + if( rc==SQLITE_OK || rc==SQLITE_DONE ){ + rc = sqlite3BtreeUpdateMeta(p->pDest,1,p->iDestSchema+1); + } if( rc==SQLITE_OK ){ if( p->pDestDb ){ sqlite3ResetAllSchemasOfConnection(p->pDestDb); @@ -444,7 +462,7 @@ int sqlite3_backup_step(sqlite3_backup *p, int nPage){ }else{ nDestTruncate = nSrcPage * (pgszSrc/pgszDest); } - sqlite3PagerTruncateImage(pDestPager, nDestTruncate); + assert( nDestTruncate>0 ); if( pgszSrc<pgszDest ){ /* If the source page-size is smaller than the destination page-size, @@ -458,22 +476,38 @@ int sqlite3_backup_step(sqlite3_backup *p, int nPage){ */ const i64 iSize = (i64)pgszSrc * (i64)nSrcPage; sqlite3_file * const pFile = sqlite3PagerFile(pDestPager); + Pgno iPg; + int nDstPage; i64 iOff; i64 iEnd; assert( pFile ); - assert( (i64)nDestTruncate*(i64)pgszDest >= iSize || ( + assert( nDestTruncate==0 + || (i64)nDestTruncate*(i64)pgszDest >= iSize || ( nDestTruncate==(int)(PENDING_BYTE_PAGE(p->pDest->pBt)-1) && iSize>=PENDING_BYTE && iSize<=PENDING_BYTE+pgszDest )); - /* This call ensures that all data required to recreate the original + /* This block ensures that all data required to recreate the original ** database has been stored in the journal for pDestPager and the ** journal synced to disk. So at this point we may safely modify ** the database file in any way, knowing that if a power failure ** occurs, the original database will be reconstructed from the ** journal file. */ - rc = sqlite3PagerCommitPhaseOne(pDestPager, 0, 1); + sqlite3PagerPagecount(pDestPager, &nDstPage); + for(iPg=nDestTruncate; rc==SQLITE_OK && iPg<=(Pgno)nDstPage; iPg++){ + if( iPg!=PENDING_BYTE_PAGE(p->pDest->pBt) ){ + DbPage *pPg; + rc = sqlite3PagerGet(pDestPager, iPg, &pPg); + if( rc==SQLITE_OK ){ + rc = sqlite3PagerWrite(pPg); + sqlite3PagerUnref(pPg); + } + } + } + if( rc==SQLITE_OK ){ + rc = sqlite3PagerCommitPhaseOne(pDestPager, 0, 1); + } /* Write the extra pages and truncate the database file as required */ iEnd = MIN(PENDING_BYTE + pgszDest, iSize); @@ -500,6 +534,7 @@ int sqlite3_backup_step(sqlite3_backup *p, int nPage){ rc = sqlite3PagerSync(pDestPager); } }else{ + sqlite3PagerTruncateImage(pDestPager, nDestTruncate); rc = sqlite3PagerCommitPhaseOne(pDestPager, 0, 0); } @@ -628,7 +663,7 @@ void sqlite3BackupUpdate(sqlite3_backup *pBackup, Pgno iPage, const u8 *aData){ int rc; assert( p->pDestDb ); sqlite3_mutex_enter(p->pDestDb->mutex); - rc = backupOnePage(p, iPage, aData); + rc = backupOnePage(p, iPage, aData, 1); sqlite3_mutex_leave(p->pDestDb->mutex); assert( rc!=SQLITE_BUSY && rc!=SQLITE_LOCKED ); if( rc!=SQLITE_OK ){ |