/* ** Usage: btree_ismemdb ID ** ** Return true if the B-Tree is currently stored entirely in memory. */ static int btree_ismemdb( void *NotUsed, Tcl_Interp *interp, /* The TCL interpreter that invoked this command */ int argc, /* Number of arguments */ const char **argv /* Text of each argument */ ){ Btree *pBt; int res; sqlite3_file *pFile; if( argc!=2 ){ Tcl_AppendResult(interp, "wrong # args: should be \"", argv[0], " ID\"", 0); return TCL_ERROR; } pBt = sqlite3TestTextToPtr(argv[1]); sqlite3_mutex_enter(pBt->db->mutex); sqlite3BtreeEnter(pBt); pFile = sqlite3PagerFile(sqlite3BtreePager(pBt)); res = (pFile->pMethods==0); sqlite3BtreeLeave(pBt); sqlite3_mutex_leave(pBt->db->mutex); Tcl_SetObjResult(interp, Tcl_NewBooleanObj(res)); return SQLITE_OK; }
/* ** Invoke the xFileControl method on a particular database. */ EXPORT_C int sqlite3_file_control(sqlite3 *db, const char *zDbName, int op, void *pArg){ int rc = SQLITE_ERROR; int iDb; sqlite3_mutex_enter(db->mutex); if( zDbName==0 ){ iDb = 0; }else{ for(iDb=0; iDb<db->nDb; iDb++){ if( strcmp(db->aDb[iDb].zName, zDbName)==0 ) break; } } if( iDb<db->nDb ){ Btree *pBtree = db->aDb[iDb].pBt; if( pBtree ){ Pager *pPager; sqlite3BtreeEnter(pBtree); pPager = sqlite3BtreePager(pBtree); if( pPager ){ sqlite3_file *fd = sqlite3PagerFile(pPager); if( fd ){ rc = sqlite3OsFileControl(fd, op, pArg); } } sqlite3BtreeLeave(pBtree); } } sqlite3_mutex_leave(db->mutex); return rc; }
/* ** Populate the pCsr->iOffset and pCsr->szPage member variables. Based on ** the current value of pCsr->iPageno. */ static void statSizeAndOffset(StatCursor *pCsr){ StatTable *pTab = (StatTable *)((sqlite3_vtab_cursor *)pCsr)->pVtab; Btree *pBt = pTab->db->aDb[pTab->iDb].pBt; Pager *pPager = sqlite3BtreePager(pBt); sqlite3_file *fd; sqlite3_int64 x[2]; /* The default page size and offset */ pCsr->szPage = sqlite3BtreeGetPageSize(pBt); pCsr->iOffset = (i64)pCsr->szPage * (pCsr->iPageno - 1); /* If connected to a ZIPVFS backend, override the page size and ** offset with actual values obtained from ZIPVFS. */ fd = sqlite3PagerFile(pPager); x[0] = pCsr->iPageno; if( fd->pMethods!=0 && sqlite3OsFileControl(fd, 230440, &x)==SQLITE_OK ){ pCsr->iOffset = x[0]; pCsr->szPage = (int)x[1]; } }
/* ** This routine implements the OP_Vacuum opcode of the VDBE. */ int sqlite3RunVacuum(char **pzErrMsg, sqlite3 *db){ int rc = SQLITE_OK; /* Return code from service routines */ Btree *pMain; /* The database being vacuumed */ Pager *pMainPager; /* Pager for database being vacuumed */ Btree *pTemp; /* The temporary database we vacuum into */ char *zSql = 0; /* SQL statements */ int saved_flags; /* Saved value of the db->flags */ int saved_nChange; /* Saved value of db->nChange */ int saved_nTotalChange; /* Saved value of db->nTotalChange */ Db *pDb = 0; /* Database to detach at end of vacuum */ int isMemDb; /* True is vacuuming a :memory: database */ int nRes; /* Save the current value of the write-schema flag before setting it. */ saved_flags = db->flags; saved_nChange = db->nChange; saved_nTotalChange = db->nTotalChange; db->flags |= SQLITE_WriteSchema | SQLITE_IgnoreChecks; if( !db->autoCommit ){ sqlite3SetString(pzErrMsg, db, "cannot VACUUM from within a transaction"); rc = SQLITE_ERROR; goto end_of_vacuum; } pMain = db->aDb[0].pBt; pMainPager = sqlite3BtreePager(pMain); isMemDb = sqlite3PagerFile(pMainPager)->pMethods==0; /* 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. */ zSql = "ATTACH '' AS vacuum_db;"; rc = execSql(db, zSql); if( rc!=SQLITE_OK ) goto end_of_vacuum; pDb = &db->aDb[db->nDb-1]; assert( strcmp(db->aDb[db->nDb-1].zName,"vacuum_db")==0 ); pTemp = db->aDb[db->nDb-1].pBt; nRes = sqlite3BtreeGetReserve(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, 0, (void**)&zKey, &nKey); if( nKey ) db->nextPagesize = 0; } #endif if( sqlite3BtreeSetPageSize(pTemp, sqlite3BtreeGetPageSize(pMain), nRes) || (!isMemDb && sqlite3BtreeSetPageSize(pTemp, db->nextPagesize, nRes)) || db->mallocFailed ){ rc = SQLITE_NOMEM; goto end_of_vacuum; } rc = execSql(db, "PRAGMA vacuum_db.synchronous=OFF"); if( rc!=SQLITE_OK ){ goto end_of_vacuum; } #ifndef SQLITE_OMIT_AUTOVACUUM sqlite3BtreeSetAutoVacuum(pTemp, db->nextAutovac>=0 ? db->nextAutovac : sqlite3BtreeGetAutoVacuum(pMain)); #endif /* Begin a transaction */ rc = execSql(db, "BEGIN EXCLUSIVE;"); if( rc!=SQLITE_OK ) goto end_of_vacuum; /* Query the schema of the main database. Create a mirror schema ** in the temporary database. */ rc = execExecSql(db, "SELECT 'CREATE TABLE vacuum_db.' || substr(sql,14) " " FROM sqlite_master WHERE type='table' AND name!='sqlite_sequence'" " AND rootpage>0" ); if( rc!=SQLITE_OK ) goto end_of_vacuum; rc = execExecSql(db, "SELECT 'CREATE INDEX vacuum_db.' || substr(sql,14)" " FROM sqlite_master WHERE sql LIKE 'CREATE INDEX %' "); if( rc!=SQLITE_OK ) goto end_of_vacuum; rc = execExecSql(db, "SELECT 'CREATE UNIQUE INDEX vacuum_db.' || substr(sql,21) " " FROM sqlite_master WHERE sql LIKE 'CREATE UNIQUE INDEX %'"); if( rc!=SQLITE_OK ) goto end_of_vacuum; /* Loop through the tables in the main database. For each, do ** an "INSERT INTO vacuum_db.xxx SELECT * FROM xxx;" to copy ** the contents to the temporary database. */ rc = execExecSql(db, "SELECT 'INSERT INTO vacuum_db.' || quote(name) " "|| ' SELECT * FROM ' || quote(name) || ';'" "FROM sqlite_master " "WHERE type = 'table' AND name!='sqlite_sequence' " " AND rootpage>0" ); if( rc!=SQLITE_OK ) goto end_of_vacuum; /* Copy over the sequence table */ rc = execExecSql(db, "SELECT 'DELETE FROM vacuum_db.' || quote(name) || ';' " "FROM vacuum_db.sqlite_master WHERE name='sqlite_sequence' " ); if( rc!=SQLITE_OK ) goto end_of_vacuum; rc = execExecSql(db, "SELECT 'INSERT INTO vacuum_db.' || quote(name) " "|| ' SELECT * FROM ' || quote(name) || ';' " "FROM vacuum_db.sqlite_master WHERE name=='sqlite_sequence';" ); 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 = execSql(db, "INSERT INTO vacuum_db.sqlite_master " " SELECT type, name, tbl_name, rootpage, sql" " FROM sqlite_master" " WHERE type='view' OR type='trigger'" " OR (type='table' AND rootpage=0)" ); if( rc ) goto end_of_vacuum; /* At this point, unless the main db was completely empty, there is now a ** transaction open on the vacuum database, but not on the main database. ** Open a btree level transaction on the main database. This allows a ** call to sqlite3BtreeCopyFile(). The main database btree level ** transaction is then committed, so the SQL level never knows it was ** opened for writing. This way, the SQL transaction used to create the ** temporary database never needs to be committed. */ if( rc==SQLITE_OK ){ 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[] = { 1, 1, /* Add one to the old schema cookie */ 3, 0, /* Preserve the default page cache size */ 5, 0, /* Preserve the default text encoding */ 6, 0, /* Preserve the user version */ }; assert( 1==sqlite3BtreeIsInTrans(pTemp) ); assert( 1==sqlite3BtreeIsInTrans(pMain) ); /* Copy Btree meta values */ for(i=0; i<ArraySize(aCopy); i+=2){ rc = sqlite3BtreeGetMeta(pMain, aCopy[i], &meta); if( rc!=SQLITE_OK ) goto end_of_vacuum; rc = sqlite3BtreeUpdateMeta(pTemp, aCopy[i], meta+aCopy[i+1]); if( 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 rc = sqlite3BtreeCommit(pMain); } if( rc==SQLITE_OK ){ rc = sqlite3BtreeSetPageSize(pMain, sqlite3BtreeGetPageSize(pTemp), nRes); } end_of_vacuum: /* Restore the original value of db->flags */ db->flags = saved_flags; db->nChange = saved_nChange; db->nTotalChange = saved_nTotalChange; /* 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; } sqlite3ResetInternalSchema(db, 0); 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 */ #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; }
/* ** 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; }
/* ** This routine implements the OP_Vacuum opcode of the VDBE. */ int sqlite3RunVacuum( char **pzErrMsg, /* Write error message here */ sqlite3 *db, /* Database connection */ int iDb, /* Which attached DB to vacuum */ sqlite3_value *pOut /* Write results here, if not NULL */ ){ int rc = SQLITE_OK; /* Return code from service routines */ Btree *pMain; /* The database being vacuumed */ Btree *pTemp; /* The temporary database we vacuum into */ u32 saved_mDbFlags; /* Saved value of db->mDbFlags */ u64 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 */ 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 */ const char *zOut; /* Name of output file */ 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; } if( pOut ){ if( sqlite3_value_type(pOut)!=SQLITE_TEXT ){ sqlite3SetString(pzErrMsg, db, "non-text filename"); return SQLITE_ERROR; } zOut = (const char*)sqlite3_value_text(pOut); }else{ zOut = ""; } /* 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 &= ~(u64)(SQLITE_ForeignKeys | SQLITE_ReverseOrder | SQLITE_Defensive | 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 = execSqlF(db, pzErrMsg, "ATTACH %Q AS vacuum_db", zOut); 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; if( pOut ){ sqlite3_file *id = sqlite3PagerFile(sqlite3BtreePager(pTemp)); i64 sz = 0; if( id->pMethods!=0 && (sqlite3OsFileSize(id, &sz)!=SQLITE_OK || sz>0) ){ rc = SQLITE_ERROR; sqlite3SetString(pzErrMsg, db, "output file already exists"); goto end_of_vacuum; } } 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, pOut==0 ? 2 : 0, 0); 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( pOut!=0 || 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; } if( pOut==0 ){ 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 if( pOut==0 ){ sqlite3BtreeSetAutoVacuum(pMain, sqlite3BtreeGetAutoVacuum(pTemp)); } #endif } assert( rc==SQLITE_OK ); if( pOut==0 ){ 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; }