/* ** Copy nPage pages from the source b-tree to the destination. */ int sqlite3_backup_step(sqlite3_backup *p, int nPage){ int rc; int destMode; /* Destination journal mode */ int pgszSrc = 0; /* Source page size */ int pgszDest = 0; /* Destination page size */ #ifdef SQLITE_ENABLE_API_ARMOR if( p==0 ) return SQLITE_MISUSE_BKPT; #endif sqlite3_mutex_enter(p->pSrcDb->mutex); sqlite3BtreeEnter(p->pSrc); if( p->pDestDb ){ sqlite3_mutex_enter(p->pDestDb->mutex); } rc = p->rc; if( !isFatalError(rc) ){ Pager * const pSrcPager = sqlite3BtreePager(p->pSrc); /* Source pager */ Pager * const pDestPager = sqlite3BtreePager(p->pDest); /* Dest pager */ int ii; /* Iterator variable */ int nSrcPage = -1; /* Size of source db in pages */ int bCloseTrans = 0; /* True if src db requires unlocking */ /* If the source pager is currently in a write-transaction, return ** SQLITE_BUSY immediately. */ if( p->pDestDb && p->pSrc->pBt->inTransaction==TRANS_WRITE ){ rc = SQLITE_BUSY; }else{ rc = SQLITE_OK; } /* If there is no open read-transaction on the source database, open ** one now. If a transaction is opened here, then it will be closed ** before this function exits. */ if( rc==SQLITE_OK && 0==sqlite3BtreeIsInReadTrans(p->pSrc) ){ rc = sqlite3BtreeBeginTrans(p->pSrc, 0, 0); bCloseTrans = 1; } /* If the destination database has not yet been locked (i.e. if this ** is the first call to backup_step() for the current backup operation), ** try to set its page size to the same as the source database. This ** is especially important on ZipVFS systems, as in that case it is ** not possible to create a database file that uses one page size by ** writing to it with another. */ if( p->bDestLocked==0 && rc==SQLITE_OK && setDestPgsz(p)==SQLITE_NOMEM ){ rc = SQLITE_NOMEM; } /* Lock the destination database, if it is not locked already. */ if( SQLITE_OK==rc && p->bDestLocked==0 && SQLITE_OK==(rc = sqlite3BtreeBeginTrans(p->pDest, 2, (int*)&p->iDestSchema)) ){ p->bDestLocked = 1; } /* Do not allow backup if the destination database is in WAL mode ** and the page sizes are different between source and destination */ pgszSrc = sqlite3BtreeGetPageSize(p->pSrc); pgszDest = sqlite3BtreeGetPageSize(p->pDest); destMode = sqlite3PagerGetJournalMode(sqlite3BtreePager(p->pDest)); if( SQLITE_OK==rc && destMode==PAGER_JOURNALMODE_WAL && pgszSrc!=pgszDest ){ rc = SQLITE_READONLY; } /* Now that there is a read-lock on the source database, query the ** source pager for the number of pages in the database. */ nSrcPage = (int)sqlite3BtreeLastPage(p->pSrc); assert( nSrcPage>=0 ); for(ii=0; (nPage<0 || ii<nPage) && p->iNext<=(Pgno)nSrcPage && !rc; ii++){ 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,PAGER_GET_READONLY); if( rc==SQLITE_OK ){ rc = backupOnePage(p, iSrcPg, sqlite3PagerGetData(pSrcPg), 0); sqlite3PagerUnref(pSrcPg); } } p->iNext++; } if( rc==SQLITE_OK ){ p->nPagecount = nSrcPage; p->nRemaining = nSrcPage+1-p->iNext; if( p->iNext>(Pgno)nSrcPage ){ rc = SQLITE_DONE; }else if( !p->isAttached ){ attachBackupObject(p); } } /* Update the schema version field in the destination database. This ** is to make sure that the schema-version really does change in ** the case where the source and destination databases have the ** same schema version. */ if( rc==SQLITE_DONE ){ 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); } if( destMode==PAGER_JOURNALMODE_WAL ){ rc = sqlite3BtreeSetVersion(p->pDest, 2); } } if( rc==SQLITE_OK ){ int nDestTruncate; /* Set nDestTruncate to the final number of pages in the destination ** database. The complication here is that the destination page ** size may be different to the source page size. ** ** If the source page size is smaller than the destination page size, ** round up. In this case the call to sqlite3OsTruncate() below will ** fix the size of the file. However it is important to call ** sqlite3PagerTruncateImage() here so that any pages in the ** destination file that lie beyond the nDestTruncate page mark are ** journalled by PagerCommitPhaseOne() before they are destroyed ** by the file truncation. */ assert( pgszSrc==sqlite3BtreeGetPageSize(p->pSrc) ); assert( pgszDest==sqlite3BtreeGetPageSize(p->pDest) ); if( pgszSrc<pgszDest ){ int ratio = pgszDest/pgszSrc; nDestTruncate = (nSrcPage+ratio-1)/ratio; if( nDestTruncate==(int)PENDING_BYTE_PAGE(p->pDest->pBt) ){ nDestTruncate--; } }else{ nDestTruncate = nSrcPage * (pgszSrc/pgszDest); } assert( nDestTruncate>0 ); if( pgszSrc<pgszDest ){ /* If the source page-size is smaller than the destination page-size, ** two extra things may need to happen: ** ** * The destination may need to be truncated, and ** ** * Data stored on the pages immediately following the ** pending-byte page in the source database may need to be ** copied into the destination database. */ const i64 iSize = (i64)pgszSrc * (i64)nSrcPage; sqlite3_file * const pFile = sqlite3PagerFile(pDestPager); Pgno iPg; int nDstPage; i64 iOff; i64 iEnd; assert( pFile ); 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 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. */ 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, 0); 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); for( iOff=PENDING_BYTE+pgszSrc; rc==SQLITE_OK && iOff<iEnd; iOff+=pgszSrc ){ PgHdr *pSrcPg = 0; const Pgno iSrcPg = (Pgno)((iOff/pgszSrc)+1); rc = sqlite3PagerGet(pSrcPager, iSrcPg, &pSrcPg, 0); if( rc==SQLITE_OK ){ u8 *zData = sqlite3PagerGetData(pSrcPg); rc = sqlite3OsWrite(pFile, zData, pgszSrc, iOff); } sqlite3PagerUnref(pSrcPg); } if( rc==SQLITE_OK ){ rc = backupTruncateFile(pFile, iSize); } /* Sync the database file to disk. */ if( rc==SQLITE_OK ){ rc = sqlite3PagerSync(pDestPager, 0); } }else{ sqlite3PagerTruncateImage(pDestPager, nDestTruncate); rc = sqlite3PagerCommitPhaseOne(pDestPager, 0, 0); } /* Finish committing the transaction to the destination database. */ if( SQLITE_OK==rc && SQLITE_OK==(rc = sqlite3BtreeCommitPhaseTwo(p->pDest, 0)) ){ rc = SQLITE_DONE; } } } /* If bCloseTrans is true, then this function opened a read transaction ** on the source database. Close the read transaction here. There is ** no need to check the return values of the btree methods here, as ** "committing" a read-only transaction cannot fail. */ if( bCloseTrans ){ TESTONLY( int rc2 ); TESTONLY( rc2 = ) sqlite3BtreeCommitPhaseOne(p->pSrc, 0); TESTONLY( rc2 |= ) sqlite3BtreeCommitPhaseTwo(p->pSrc, 0); assert( rc2==SQLITE_OK ); } if( rc==SQLITE_IOERR_NOMEM ){ rc = SQLITE_NOMEM_BKPT; } p->rc = rc; }
/* CHANGE 1 of 3: Add function parameter nRes */ SQLITE_PRIVATE int sqlite3RunVacuumForRekey(char **pzErrMsg, sqlite3 *db, int iDb, int nRes){ int rc = SQLITE_OK; /* Return code from service routines */ Btree *pMain; /* The database being vacuumed */ Btree *pTemp; /* The temporary database we vacuum into */ u16 saved_mDbFlags; /* Saved value of db->mDbFlags */ u32 saved_flags; /* Saved value of db->flags */ int saved_nChange; /* Saved value of db->nChange */ int saved_nTotalChange; /* Saved value of db->nTotalChange */ u8 saved_mTrace; /* Saved trace settings */ Db *pDb = 0; /* Database to detach at end of vacuum */ int isMemDb; /* True if vacuuming a :memory: database */ /* CHANGE 2 of 3: Do not define local variable nRes */ /*int nRes;*/ /* Bytes of reserved space at the end of each page */ int nDb; /* Number of attached databases */ const char *zDbMain; /* Schema name of database to vacuum */ if (!db->autoCommit) { sqlite3SetString(pzErrMsg, db, "cannot VACUUM from within a transaction"); return SQLITE_ERROR; } if (db->nVdbeActive>1) { sqlite3SetString(pzErrMsg, db, "cannot VACUUM - SQL statements in progress"); return SQLITE_ERROR; } /* Save the current value of the database flags so that it can be ** restored before returning. Then set the writable-schema flag, and ** disable CHECK and foreign key constraints. */ saved_flags = db->flags; saved_mDbFlags = db->mDbFlags; saved_nChange = db->nChange; saved_nTotalChange = db->nTotalChange; saved_mTrace = db->mTrace; db->flags |= SQLITE_WriteSchema | SQLITE_IgnoreChecks; db->mDbFlags |= DBFLAG_PreferBuiltin | DBFLAG_Vacuum; db->flags &= ~(SQLITE_ForeignKeys | SQLITE_ReverseOrder | SQLITE_CountRows); db->mTrace = 0; zDbMain = db->aDb[iDb].zDbSName; pMain = db->aDb[iDb].pBt; isMemDb = sqlite3PagerIsMemdb(sqlite3BtreePager(pMain)); /* Attach the temporary database as 'vacuum_db'. The synchronous pragma ** can be set to 'off' for this file, as it is not recovered if a crash ** occurs anyway. The integrity of the database is maintained by a ** (possibly synchronous) transaction opened on the main database before ** sqlite3BtreeCopyFile() is called. ** ** An optimisation would be to use a non-journaled pager. ** (Later:) I tried setting "PRAGMA vacuum_db.journal_mode=OFF" but ** that actually made the VACUUM run slower. Very little journalling ** actually occurs when doing a vacuum since the vacuum_db is initially ** empty. Only the journal header is written. Apparently it takes more ** time to parse and run the PRAGMA to turn journalling off than it does ** to write the journal header file. */ nDb = db->nDb; rc = execSql(db, pzErrMsg, "ATTACH''AS vacuum_db"); if (rc != SQLITE_OK) goto end_of_vacuum; assert((db->nDb - 1) == nDb); pDb = &db->aDb[nDb]; assert(strcmp(pDb->zDbSName, "vacuum_db") == 0); pTemp = pDb->pBt; /* The call to execSql() to attach the temp database has left the file ** locked (as there was more than one active statement when the transaction ** to read the schema was concluded. Unlock it here so that this doesn't ** cause problems for the call to BtreeSetPageSize() below. */ sqlite3BtreeCommit(pTemp); /* CHANGE 3 of 3: Do not call sqlite3BtreeGetOptimalReserve */ /* nRes = sqlite3BtreeGetOptimalReserve(pMain); */ /* A VACUUM cannot change the pagesize of an encrypted database. */ #ifdef SQLITE_HAS_CODEC if (db->nextPagesize) { extern void sqlite3CodecGetKey(sqlite3*, int, void**, int*); int nKey; char *zKey; sqlite3CodecGetKey(db, iDb, (void**)&zKey, &nKey); if (nKey) db->nextPagesize = 0; } #endif sqlite3BtreeSetCacheSize(pTemp, db->aDb[iDb].pSchema->cache_size); sqlite3BtreeSetSpillSize(pTemp, sqlite3BtreeSetSpillSize(pMain, 0)); sqlite3BtreeSetPagerFlags(pTemp, PAGER_SYNCHRONOUS_OFF | PAGER_CACHESPILL); /* Begin a transaction and take an exclusive lock on the main database ** file. This is done before the sqlite3BtreeGetPageSize(pMain) call below, ** to ensure that we do not try to change the page-size on a WAL database. */ rc = execSql(db, pzErrMsg, "BEGIN"); if (rc != SQLITE_OK) goto end_of_vacuum; rc = sqlite3BtreeBeginTrans(pMain, 2); if (rc != SQLITE_OK) goto end_of_vacuum; /* Do not attempt to change the page size for a WAL database */ if (sqlite3PagerGetJournalMode(sqlite3BtreePager(pMain)) == PAGER_JOURNALMODE_WAL) { db->nextPagesize = 0; } if (sqlite3BtreeSetPageSize(pTemp, sqlite3BtreeGetPageSize(pMain), nRes, 0) || (!isMemDb && sqlite3BtreeSetPageSize(pTemp, db->nextPagesize, nRes, 0)) || NEVER(db->mallocFailed) ) { rc = SQLITE_NOMEM_BKPT; goto end_of_vacuum; } #ifndef SQLITE_OMIT_AUTOVACUUM sqlite3BtreeSetAutoVacuum(pTemp, db->nextAutovac >= 0 ? db->nextAutovac : sqlite3BtreeGetAutoVacuum(pMain)); #endif /* Query the schema of the main database. Create a mirror schema ** in the temporary database. */ db->init.iDb = nDb; /* force new CREATE statements into vacuum_db */ rc = execSqlF(db, pzErrMsg, "SELECT sql FROM \"%w\".sqlite_master" " WHERE type='table'AND name<>'sqlite_sequence'" " AND coalesce(rootpage,1)>0", zDbMain ); if (rc != SQLITE_OK) goto end_of_vacuum; rc = execSqlF(db, pzErrMsg, "SELECT sql FROM \"%w\".sqlite_master" " WHERE type='index'", zDbMain ); if (rc != SQLITE_OK) goto end_of_vacuum; db->init.iDb = 0; /* Loop through the tables in the main database. For each, do ** an "INSERT INTO vacuum_db.xxx SELECT * FROM main.xxx;" to copy ** the contents to the temporary database. */ rc = execSqlF(db, pzErrMsg, "SELECT'INSERT INTO vacuum_db.'||quote(name)" "||' SELECT*FROM\"%w\".'||quote(name)" "FROM vacuum_db.sqlite_master " "WHERE type='table'AND coalesce(rootpage,1)>0", zDbMain ); assert((db->mDbFlags & DBFLAG_Vacuum) != 0); db->mDbFlags &= ~DBFLAG_Vacuum; if (rc != SQLITE_OK) goto end_of_vacuum; /* Copy the triggers, views, and virtual tables from the main database ** over to the temporary database. None of these objects has any ** associated storage, so all we have to do is copy their entries ** from the SQLITE_MASTER table. */ rc = execSqlF(db, pzErrMsg, "INSERT INTO vacuum_db.sqlite_master" " SELECT*FROM \"%w\".sqlite_master" " WHERE type IN('view','trigger')" " OR(type='table'AND rootpage=0)", zDbMain ); if (rc) goto end_of_vacuum; /* At this point, there is a write transaction open on both the ** vacuum database and the main database. Assuming no error occurs, ** both transactions are closed by this block - the main database ** transaction by sqlite3BtreeCopyFile() and the other by an explicit ** call to sqlite3BtreeCommit(). */ { u32 meta; int i; /* This array determines which meta meta values are preserved in the ** vacuum. Even entries are the meta value number and odd entries ** are an increment to apply to the meta value after the vacuum. ** The increment is used to increase the schema cookie so that other ** connections to the same database will know to reread the schema. */ static const unsigned char aCopy[] = { BTREE_SCHEMA_VERSION, 1, /* Add one to the old schema cookie */ BTREE_DEFAULT_CACHE_SIZE, 0, /* Preserve the default page cache size */ BTREE_TEXT_ENCODING, 0, /* Preserve the text encoding */ BTREE_USER_VERSION, 0, /* Preserve the user version */ BTREE_APPLICATION_ID, 0, /* Preserve the application id */ }; assert(1 == sqlite3BtreeIsInTrans(pTemp)); assert(1 == sqlite3BtreeIsInTrans(pMain)); /* Copy Btree meta values */ for (i = 0; i<ArraySize(aCopy); i += 2) { /* GetMeta() and UpdateMeta() cannot fail in this context because ** we already have page 1 loaded into cache and marked dirty. */ sqlite3BtreeGetMeta(pMain, aCopy[i], &meta); rc = sqlite3BtreeUpdateMeta(pTemp, aCopy[i], meta + aCopy[i + 1]); if (NEVER(rc != SQLITE_OK)) goto end_of_vacuum; } rc = sqlite3BtreeCopyFile(pMain, pTemp); if (rc != SQLITE_OK) goto end_of_vacuum; rc = sqlite3BtreeCommit(pTemp); if (rc != SQLITE_OK) goto end_of_vacuum; #ifndef SQLITE_OMIT_AUTOVACUUM sqlite3BtreeSetAutoVacuum(pMain, sqlite3BtreeGetAutoVacuum(pTemp)); #endif } assert(rc == SQLITE_OK); rc = sqlite3BtreeSetPageSize(pMain, sqlite3BtreeGetPageSize(pTemp), nRes, 1); end_of_vacuum: /* Restore the original value of db->flags */ db->init.iDb = 0; db->mDbFlags = saved_mDbFlags; db->flags = saved_flags; db->nChange = saved_nChange; db->nTotalChange = saved_nTotalChange; db->mTrace = saved_mTrace; sqlite3BtreeSetPageSize(pMain, -1, -1, 1); /* Currently there is an SQL level transaction open on the vacuum ** database. No locks are held on any other files (since the main file ** was committed at the btree level). So it safe to end the transaction ** by manually setting the autoCommit flag to true and detaching the ** vacuum database. The vacuum_db journal file is deleted when the pager ** is closed by the DETACH. */ db->autoCommit = 1; if (pDb) { sqlite3BtreeClose(pDb->pBt); pDb->pBt = 0; pDb->pSchema = 0; } /* This both clears the schemas and reduces the size of the db->aDb[] ** array. */ sqlite3ResetAllSchemasOfConnection(db); return rc; }
/* ** Copy nPage pages from the source b-tree to the destination. */ int sqlite3_backup_step(sqlite3_backup *p, int nPage){ int rc; int destMode; /* Destination journal mode */ int pgszSrc = 0; /* Source page size */ int pgszDest = 0; /* Destination page size */ sqlite3_mutex_enter(p->pSrcDb->mutex); sqlite3BtreeEnter(p->pSrc); if( p->pDestDb ){ sqlite3_mutex_enter(p->pDestDb->mutex); } rc = p->rc; if( !isFatalError(rc) ){ Pager * const pSrcPager = sqlite3BtreePager(p->pSrc); /* Source pager */ Pager * const pDestPager = sqlite3BtreePager(p->pDest); /* Dest pager */ int ii; /* Iterator variable */ int nSrcPage = -1; /* Size of source db in pages */ int bCloseTrans = 0; /* True if src db requires unlocking */ /* If the source pager is currently in a write-transaction, return ** SQLITE_BUSY immediately. */ if( p->pDestDb && p->pSrc->pBt->inTransaction==TRANS_WRITE ){ rc = SQLITE_BUSY; }else{ rc = SQLITE_OK; } /* Lock the destination database, if it is not locked already. */ if( SQLITE_OK==rc && p->bDestLocked==0 && SQLITE_OK==(rc = sqlite3BtreeBeginTrans(p->pDest, 2)) ){ p->bDestLocked = 1; sqlite3BtreeGetMeta(p->pDest, BTREE_SCHEMA_VERSION, &p->iDestSchema); } /* If there is no open read-transaction on the source database, open ** one now. If a transaction is opened here, then it will be closed ** before this function exits. */ if( rc==SQLITE_OK && 0==sqlite3BtreeIsInReadTrans(p->pSrc) ){ rc = sqlite3BtreeBeginTrans(p->pSrc, 0); bCloseTrans = 1; } /* Do not allow backup if the destination database is in WAL mode ** and the page sizes are different between source and destination */ pgszSrc = sqlite3BtreeGetPageSize(p->pSrc); pgszDest = sqlite3BtreeGetPageSize(p->pDest); destMode = sqlite3PagerGetJournalMode(sqlite3BtreePager(p->pDest)); if( SQLITE_OK==rc && destMode==PAGER_JOURNALMODE_WAL && pgszSrc!=pgszDest ){ rc = SQLITE_READONLY; } /* Now that there is a read-lock on the source database, query the ** source pager for the number of pages in the database. */ nSrcPage = (int)sqlite3BtreeLastPage(p->pSrc); assert( nSrcPage>=0 ); for(ii=0; (nPage<0 || ii<nPage) && p->iNext<=(Pgno)nSrcPage && !rc; ii++){ 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); if( rc==SQLITE_OK ){ rc = backupOnePage(p, iSrcPg, sqlite3PagerGetData(pSrcPg)); sqlite3PagerUnref(pSrcPg); } } p->iNext++; } if( rc==SQLITE_OK ){ p->nPagecount = nSrcPage; p->nRemaining = nSrcPage+1-p->iNext; if( p->iNext>(Pgno)nSrcPage ){ rc = SQLITE_DONE; }else if( !p->isAttached ){ attachBackupObject(p); } } /* Update the schema version field in the destination database. This ** is to make sure that the schema-version really does change in ** the case where the source and destination databases have the ** same schema version. */ if( rc==SQLITE_DONE && (rc = sqlite3BtreeUpdateMeta(p->pDest,1,p->iDestSchema+1))==SQLITE_OK ){ int nDestTruncate; if( p->pDestDb ){ sqlite3ResetInternalSchema(p->pDestDb, 0); } /* Set nDestTruncate to the final number of pages in the destination ** database. The complication here is that the destination page ** size may be different to the source page size. ** ** If the source page size is smaller than the destination page size, ** round up. In this case the call to sqlite3OsTruncate() below will ** fix the size of the file. However it is important to call ** sqlite3PagerTruncateImage() here so that any pages in the ** destination file that lie beyond the nDestTruncate page mark are ** journalled by PagerCommitPhaseOne() before they are destroyed ** by the file truncation. */ assert( pgszSrc==sqlite3BtreeGetPageSize(p->pSrc) ); assert( pgszDest==sqlite3BtreeGetPageSize(p->pDest) ); if( pgszSrc<pgszDest ){ int ratio = pgszDest/pgszSrc; nDestTruncate = (nSrcPage+ratio-1)/ratio; if( nDestTruncate==(int)PENDING_BYTE_PAGE(p->pDest->pBt) ){ nDestTruncate--; } }else{ nDestTruncate = nSrcPage * (pgszSrc/pgszDest); } sqlite3PagerTruncateImage(pDestPager, nDestTruncate); if( pgszSrc<pgszDest ){ /* If the source page-size is smaller than the destination page-size, ** two extra things may need to happen: ** ** * The destination may need to be truncated, and ** ** * Data stored on the pages immediately following the ** pending-byte page in the source database may need to be ** copied into the destination database. */ const i64 iSize = (i64)pgszSrc * (i64)nSrcPage; sqlite3_file * const pFile = sqlite3PagerFile(pDestPager); assert( pFile ); assert( (i64)nDestTruncate*(i64)pgszDest >= iSize || ( nDestTruncate==(int)(PENDING_BYTE_PAGE(p->pDest->pBt)-1) && iSize>=PENDING_BYTE && iSize<=PENDING_BYTE+pgszDest )); if( SQLITE_OK==(rc = sqlite3PagerCommitPhaseOne(pDestPager, 0, 1)) && SQLITE_OK==(rc = backupTruncateFile(pFile, iSize)) && SQLITE_OK==(rc = sqlite3PagerSync(pDestPager)) ){ i64 iOff; i64 iEnd = MIN(PENDING_BYTE + pgszDest, iSize); for( iOff=PENDING_BYTE+pgszSrc; rc==SQLITE_OK && iOff<iEnd; iOff+=pgszSrc ){ PgHdr *pSrcPg = 0; const Pgno iSrcPg = (Pgno)((iOff/pgszSrc)+1); rc = sqlite3PagerGet(pSrcPager, iSrcPg, &pSrcPg); if( rc==SQLITE_OK ){ u8 *zData = sqlite3PagerGetData(pSrcPg); rc = sqlite3OsWrite(pFile, zData, pgszSrc, iOff); } sqlite3PagerUnref(pSrcPg); } } }else{ rc = sqlite3PagerCommitPhaseOne(pDestPager, 0, 0); } /* Finish committing the transaction to the destination database. */ if( SQLITE_OK==rc && SQLITE_OK==(rc = sqlite3BtreeCommitPhaseTwo(p->pDest)) ){ rc = SQLITE_DONE; } } /* If bCloseTrans is true, then this function opened a read transaction ** on the source database. Close the read transaction here. There is ** no need to check the return values of the btree methods here, as ** "committing" a read-only transaction cannot fail. */ if( bCloseTrans ){ TESTONLY( int rc2 ); TESTONLY( rc2 = ) sqlite3BtreeCommitPhaseOne(p->pSrc, 0); TESTONLY( rc2 |= ) sqlite3BtreeCommitPhaseTwo(p->pSrc); assert( rc2==SQLITE_OK ); } if( rc==SQLITE_IOERR_NOMEM ){ rc = SQLITE_NOMEM; } p->rc = rc; }