/* ** This routine generates code that opens the sqlite_stat1 table on cursor ** iStatCur. ** ** If the sqlite_stat1 tables does not previously exist, it is created. ** If it does previously exist, all entires associated with table zWhere ** are removed. If zWhere==0 then all entries are removed. */ static void openStatTable( Parse *pParse, /* Parsing context */ int iDb, /* The database we are looking in */ int iStatCur, /* Open the sqlite_stat1 table on this cursor */ const char *zWhere /* Delete entries associated with this table */ ){ sqlite3 *db = pParse->db; Db *pDb; int iRootPage; Table *pStat; Vdbe *v = sqlite3GetVdbe(pParse); if( v==0 ) return; assert( sqlite3BtreeHoldsAllMutexes(db) ); assert( sqlite3VdbeDb(v)==db ); pDb = &db->aDb[iDb]; if( (pStat = sqlite3FindTable(db, "sqlite_stat1", pDb->zName))==0 ){ /* The sqlite_stat1 tables does not exist. Create it. ** Note that a side-effect of the CREATE TABLE statement is to leave ** the rootpage of the new table on the top of the stack. This is ** important because the OpenWrite opcode below will be needing it. */ sqlite3NestedParse(pParse, "CREATE TABLE %Q.sqlite_stat1(tbl,idx,stat)", pDb->zName ); iRootPage = 0; /* Cause rootpage to be taken from top of stack */ }else if( zWhere ){ /* The sqlite_stat1 table exists. Delete all entries associated with ** the table zWhere. */ sqlite3NestedParse(pParse, "DELETE FROM %Q.sqlite_stat1 WHERE tbl=%Q", pDb->zName, zWhere ); iRootPage = pStat->tnum; }else{ /* The sqlite_stat1 table already exists. Delete all rows. */ iRootPage = pStat->tnum; sqlite3VdbeAddOp(v, OP_Clear, pStat->tnum, iDb); } /* Open the sqlite_stat1 table for writing. Unless it was created ** by this vdbe program, lock it for writing at the shared-cache level. ** If this vdbe did create the sqlite_stat1 table, then it must have ** already obtained a schema-lock, making the write-lock redundant. */ if( iRootPage>0 ){ sqlite3TableLock(pParse, iDb, iRootPage, 1, "sqlite_stat1"); } sqlite3VdbeAddOp(v, OP_Integer, iDb, 0); sqlite3VdbeAddOp(v, OP_OpenWrite, iStatCur, iRootPage); sqlite3VdbeAddOp(v, OP_SetNumColumns, iStatCur, 3); }
/* ** Generate code that will open a table for reading. */ void sqlite3OpenTable( Parse *p, /* Generate code into this VDBE */ int iCur, /* The cursor number of the table */ int iDb, /* The database index in sqlite3.aDb[] */ Table *pTab, /* The table to be opened */ int opcode /* OP_OpenRead or OP_OpenWrite */ ){ Vdbe *v = sqlite3GetVdbe(p); assert( opcode==OP_OpenWrite || opcode==OP_OpenRead ); sqlite3TableLock(p, iDb, pTab->tnum, (opcode==OP_OpenWrite), pTab->zName); sqlite3VdbeAddOp(v, OP_Integer, iDb, 0); VdbeComment((v, "# %s", pTab->zName)); sqlite3VdbeAddOp(v, opcode, iCur, pTab->tnum); sqlite3VdbeAddOp(v, OP_SetNumColumns, iCur, pTab->nCol); }
/* ** Generate code for a DELETE FROM statement. ** ** DELETE FROM table_wxyz WHERE a<5 AND b NOT NULL; ** \________/ \________________/ ** pTabList pWhere */ void sqlite3DeleteFrom( Parse *pParse, /* The parser context */ SrcList *pTabList, /* The table from which we should delete things */ Expr *pWhere /* The WHERE clause. May be null */ ){ Vdbe *v; /* The virtual database engine */ Table *pTab; /* The table from which records will be deleted */ int i; /* Loop counter */ WhereInfo *pWInfo; /* Information about the WHERE clause */ Index *pIdx; /* For looping over indices of the table */ int iTabCur; /* Cursor number for the table */ int iDataCur = 0; /* VDBE cursor for the canonical data source */ int iIdxCur = 0; /* Cursor number of the first index */ int nIdx; /* Number of indices */ sqlite3 *db; /* Main database structure */ AuthContext sContext; /* Authorization context */ NameContext sNC; /* Name context to resolve expressions in */ int iDb; /* Database number */ int memCnt = -1; /* Memory cell used for change counting */ int rcauth; /* Value returned by authorization callback */ int eOnePass; /* ONEPASS_OFF or _SINGLE or _MULTI */ int aiCurOnePass[2]; /* The write cursors opened by WHERE_ONEPASS */ u8 *aToOpen = 0; /* Open cursor iTabCur+j if aToOpen[j] is true */ Index *pPk; /* The PRIMARY KEY index on the table */ int iPk = 0; /* First of nPk registers holding PRIMARY KEY value */ i16 nPk = 1; /* Number of columns in the PRIMARY KEY */ int iKey; /* Memory cell holding key of row to be deleted */ i16 nKey; /* Number of memory cells in the row key */ int iEphCur = 0; /* Ephemeral table holding all primary key values */ int iRowSet = 0; /* Register for rowset of rows to delete */ int addrBypass = 0; /* Address of jump over the delete logic */ int addrLoop = 0; /* Top of the delete loop */ int addrEphOpen = 0; /* Instruction to open the Ephemeral table */ int bComplex; /* True if there are triggers or FKs or ** subqueries in the WHERE clause */ #ifndef SQLITE_OMIT_TRIGGER int isView; /* True if attempting to delete from a view */ Trigger *pTrigger; /* List of table triggers, if required */ #endif memset(&sContext, 0, sizeof(sContext)); db = pParse->db; if( pParse->nErr || db->mallocFailed ){ goto delete_from_cleanup; } assert( pTabList->nSrc==1 ); /* Locate the table which we want to delete. This table has to be ** put in an SrcList structure because some of the subroutines we ** will be calling are designed to work with multiple tables and expect ** an SrcList* parameter instead of just a Table* parameter. */ pTab = sqlite3SrcListLookup(pParse, pTabList); if( pTab==0 ) goto delete_from_cleanup; /* Figure out if we have any triggers and if the table being ** deleted from is a view */ #ifndef SQLITE_OMIT_TRIGGER pTrigger = sqlite3TriggersExist(pParse, pTab, TK_DELETE, 0, 0); isView = pTab->pSelect!=0; bComplex = pTrigger || sqlite3FkRequired(pParse, pTab, 0, 0); #else # define pTrigger 0 # define isView 0 #endif #ifdef SQLITE_OMIT_VIEW # undef isView # define isView 0 #endif /* If pTab is really a view, make sure it has been initialized. */ if( sqlite3ViewGetColumnNames(pParse, pTab) ){ goto delete_from_cleanup; } if( sqlite3IsReadOnly(pParse, pTab, (pTrigger?1:0)) ){ goto delete_from_cleanup; } iDb = sqlite3SchemaToIndex(db, pTab->pSchema); assert( iDb<db->nDb ); rcauth = sqlite3AuthCheck(pParse, SQLITE_DELETE, pTab->zName, 0, db->aDb[iDb].zDbSName); assert( rcauth==SQLITE_OK || rcauth==SQLITE_DENY || rcauth==SQLITE_IGNORE ); if( rcauth==SQLITE_DENY ){ goto delete_from_cleanup; } assert(!isView || pTrigger); /* Assign cursor numbers to the table and all its indices. */ assert( pTabList->nSrc==1 ); iTabCur = pTabList->a[0].iCursor = pParse->nTab++; for(nIdx=0, pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext, nIdx++){ pParse->nTab++; } /* Start the view context */ if( isView ){ sqlite3AuthContextPush(pParse, &sContext, pTab->zName); } /* Begin generating code. */ v = sqlite3GetVdbe(pParse); if( v==0 ){ goto delete_from_cleanup; } if( pParse->nested==0 ) sqlite3VdbeCountChanges(v); sqlite3BeginWriteOperation(pParse, 1, iDb); /* If we are trying to delete from a view, realize that view into ** an ephemeral table. */ #if !defined(SQLITE_OMIT_VIEW) && !defined(SQLITE_OMIT_TRIGGER) if( isView ){ sqlite3MaterializeView(pParse, pTab, pWhere, iTabCur); iDataCur = iIdxCur = iTabCur; } #endif /* Resolve the column names in the WHERE clause. */ memset(&sNC, 0, sizeof(sNC)); sNC.pParse = pParse; sNC.pSrcList = pTabList; if( sqlite3ResolveExprNames(&sNC, pWhere) ){ goto delete_from_cleanup; } /* Initialize the counter of the number of rows deleted, if ** we are counting rows. */ if( db->flags & SQLITE_CountRows ){ memCnt = ++pParse->nMem; sqlite3VdbeAddOp2(v, OP_Integer, 0, memCnt); } #ifndef SQLITE_OMIT_TRUNCATE_OPTIMIZATION /* Special case: A DELETE without a WHERE clause deletes everything. ** It is easier just to erase the whole table. Prior to version 3.6.5, ** this optimization caused the row change count (the value returned by ** API function sqlite3_count_changes) to be set incorrectly. */ if( rcauth==SQLITE_OK && pWhere==0 && !bComplex && !IsVirtual(pTab) #ifdef SQLITE_ENABLE_PREUPDATE_HOOK && db->xPreUpdateCallback==0 #endif ){ assert( !isView ); sqlite3TableLock(pParse, iDb, pTab->tnum, 1, pTab->zName); if( HasRowid(pTab) ){ sqlite3VdbeAddOp4(v, OP_Clear, pTab->tnum, iDb, memCnt, pTab->zName, P4_STATIC); } for(pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext){ assert( pIdx->pSchema==pTab->pSchema ); sqlite3VdbeAddOp2(v, OP_Clear, pIdx->tnum, iDb); } }else #endif /* SQLITE_OMIT_TRUNCATE_OPTIMIZATION */ { u16 wcf = WHERE_ONEPASS_DESIRED|WHERE_DUPLICATES_OK|WHERE_SEEK_TABLE; if( sNC.ncFlags & NC_VarSelect ) bComplex = 1; wcf |= (bComplex ? 0 : WHERE_ONEPASS_MULTIROW); if( HasRowid(pTab) ){ /* For a rowid table, initialize the RowSet to an empty set */ pPk = 0; nPk = 1; iRowSet = ++pParse->nMem; sqlite3VdbeAddOp2(v, OP_Null, 0, iRowSet); }else{ /* For a WITHOUT ROWID table, create an ephemeral table used to ** hold all primary keys for rows to be deleted. */ pPk = sqlite3PrimaryKeyIndex(pTab); assert( pPk!=0 ); nPk = pPk->nKeyCol; iPk = pParse->nMem+1; pParse->nMem += nPk; iEphCur = pParse->nTab++; addrEphOpen = sqlite3VdbeAddOp2(v, OP_OpenEphemeral, iEphCur, nPk); sqlite3VdbeSetP4KeyInfo(pParse, pPk); } /* Construct a query to find the rowid or primary key for every row ** to be deleted, based on the WHERE clause. Set variable eOnePass ** to indicate the strategy used to implement this delete: ** ** ONEPASS_OFF: Two-pass approach - use a FIFO for rowids/PK values. ** ONEPASS_SINGLE: One-pass approach - at most one row deleted. ** ONEPASS_MULTI: One-pass approach - any number of rows may be deleted. */ pWInfo = sqlite3WhereBegin(pParse, pTabList, pWhere, 0, 0, wcf, iTabCur+1); if( pWInfo==0 ) goto delete_from_cleanup; eOnePass = sqlite3WhereOkOnePass(pWInfo, aiCurOnePass); assert( IsVirtual(pTab)==0 || eOnePass!=ONEPASS_MULTI ); assert( IsVirtual(pTab) || bComplex || eOnePass!=ONEPASS_OFF ); /* Keep track of the number of rows to be deleted */ if( db->flags & SQLITE_CountRows ){ sqlite3VdbeAddOp2(v, OP_AddImm, memCnt, 1); } /* Extract the rowid or primary key for the current row */ if( pPk ){ for(i=0; i<nPk; i++){ assert( pPk->aiColumn[i]>=0 ); sqlite3ExprCodeGetColumnOfTable(v, pTab, iTabCur, pPk->aiColumn[i], iPk+i); } iKey = iPk; }else{ iKey = pParse->nMem + 1; iKey = sqlite3ExprCodeGetColumn(pParse, pTab, -1, iTabCur, iKey, 0); if( iKey>pParse->nMem ) pParse->nMem = iKey; } if( eOnePass!=ONEPASS_OFF ){ /* For ONEPASS, no need to store the rowid/primary-key. There is only ** one, so just keep it in its register(s) and fall through to the ** delete code. */ nKey = nPk; /* OP_Found will use an unpacked key */ aToOpen = sqlite3DbMallocRawNN(db, nIdx+2); if( aToOpen==0 ){ sqlite3WhereEnd(pWInfo); goto delete_from_cleanup; } memset(aToOpen, 1, nIdx+1); aToOpen[nIdx+1] = 0; if( aiCurOnePass[0]>=0 ) aToOpen[aiCurOnePass[0]-iTabCur] = 0; if( aiCurOnePass[1]>=0 ) aToOpen[aiCurOnePass[1]-iTabCur] = 0; if( addrEphOpen ) sqlite3VdbeChangeToNoop(v, addrEphOpen); }else{ if( pPk ){ /* Add the PK key for this row to the temporary table */ iKey = ++pParse->nMem; nKey = 0; /* Zero tells OP_Found to use a composite key */ sqlite3VdbeAddOp4(v, OP_MakeRecord, iPk, nPk, iKey, sqlite3IndexAffinityStr(pParse->db, pPk), nPk); sqlite3VdbeAddOp2(v, OP_IdxInsert, iEphCur, iKey); }else{ /* Add the rowid of the row to be deleted to the RowSet */ nKey = 1; /* OP_Seek always uses a single rowid */ sqlite3VdbeAddOp2(v, OP_RowSetAdd, iRowSet, iKey); } } /* If this DELETE cannot use the ONEPASS strategy, this is the ** end of the WHERE loop */ if( eOnePass!=ONEPASS_OFF ){ addrBypass = sqlite3VdbeMakeLabel(v); }else{ sqlite3WhereEnd(pWInfo); } /* Unless this is a view, open cursors for the table we are ** deleting from and all its indices. If this is a view, then the ** only effect this statement has is to fire the INSTEAD OF ** triggers. */ if( !isView ){ int iAddrOnce = 0; if( eOnePass==ONEPASS_MULTI ){ iAddrOnce = sqlite3VdbeAddOp0(v, OP_Once); VdbeCoverage(v); } testcase( IsVirtual(pTab) ); sqlite3OpenTableAndIndices(pParse, pTab, OP_OpenWrite, OPFLAG_FORDELETE, iTabCur, aToOpen, &iDataCur, &iIdxCur); assert( pPk || IsVirtual(pTab) || iDataCur==iTabCur ); assert( pPk || IsVirtual(pTab) || iIdxCur==iDataCur+1 ); if( eOnePass==ONEPASS_MULTI ) sqlite3VdbeJumpHere(v, iAddrOnce); } /* Set up a loop over the rowids/primary-keys that were found in the ** where-clause loop above. */ if( eOnePass!=ONEPASS_OFF ){ assert( nKey==nPk ); /* OP_Found will use an unpacked key */ if( !IsVirtual(pTab) && aToOpen[iDataCur-iTabCur] ){ assert( pPk!=0 || pTab->pSelect!=0 ); sqlite3VdbeAddOp4Int(v, OP_NotFound, iDataCur, addrBypass, iKey, nKey); VdbeCoverage(v); } }else if( pPk ){ addrLoop = sqlite3VdbeAddOp1(v, OP_Rewind, iEphCur); VdbeCoverage(v); sqlite3VdbeAddOp2(v, OP_RowKey, iEphCur, iKey); assert( nKey==0 ); /* OP_Found will use a composite key */ }else{ addrLoop = sqlite3VdbeAddOp3(v, OP_RowSetRead, iRowSet, 0, iKey); VdbeCoverage(v); assert( nKey==1 ); } /* Delete the row */ #ifndef SQLITE_OMIT_VIRTUALTABLE if( IsVirtual(pTab) ){ const char *pVTab = (const char *)sqlite3GetVTable(db, pTab); sqlite3VtabMakeWritable(pParse, pTab); sqlite3VdbeAddOp4(v, OP_VUpdate, 0, 1, iKey, pVTab, P4_VTAB); sqlite3VdbeChangeP5(v, OE_Abort); assert( eOnePass==ONEPASS_OFF || eOnePass==ONEPASS_SINGLE ); sqlite3MayAbort(pParse); if( eOnePass==ONEPASS_SINGLE && sqlite3IsToplevel(pParse) ){ pParse->isMultiWrite = 0; } }else #endif { int count = (pParse->nested==0); /* True to count changes */ int iIdxNoSeek = -1; if( bComplex==0 && aiCurOnePass[1]!=iDataCur ){ iIdxNoSeek = aiCurOnePass[1]; } sqlite3GenerateRowDelete(pParse, pTab, pTrigger, iDataCur, iIdxCur, iKey, nKey, count, OE_Default, eOnePass, iIdxNoSeek); } /* End of the loop over all rowids/primary-keys. */ if( eOnePass!=ONEPASS_OFF ){ sqlite3VdbeResolveLabel(v, addrBypass); sqlite3WhereEnd(pWInfo); }else if( pPk ){ sqlite3VdbeAddOp2(v, OP_Next, iEphCur, addrLoop+1); VdbeCoverage(v); sqlite3VdbeJumpHere(v, addrLoop); }else{ sqlite3VdbeGoto(v, addrLoop); sqlite3VdbeJumpHere(v, addrLoop); } /* Close the cursors open on the table and its indexes. */ if( !isView && !IsVirtual(pTab) ){ if( !pPk ) sqlite3VdbeAddOp1(v, OP_Close, iDataCur); for(i=0, pIdx=pTab->pIndex; pIdx; i++, pIdx=pIdx->pNext){ sqlite3VdbeAddOp1(v, OP_Close, iIdxCur + i); } } } /* End non-truncate path */ /* Update the sqlite_sequence table by storing the content of the ** maximum rowid counter values recorded while inserting into ** autoincrement tables. */ if( pParse->nested==0 && pParse->pTriggerTab==0 ){ sqlite3AutoincrementEnd(pParse); } /* Return the number of rows that were deleted. If this routine is ** generating code because of a call to sqlite3NestedParse(), do not ** invoke the callback function. */ if( (db->flags&SQLITE_CountRows) && !pParse->nested && !pParse->pTriggerTab ){ sqlite3VdbeAddOp2(v, OP_ResultRow, memCnt, 1); sqlite3VdbeSetNumCols(v, 1); sqlite3VdbeSetColName(v, 0, COLNAME_NAME, "rows deleted", SQLITE_STATIC); } delete_from_cleanup: sqlite3AuthContextPop(&sContext); sqlite3SrcListDelete(db, pTabList); sqlite3ExprDelete(db, pWhere); sqlite3DbFree(db, aToOpen); return; }
/* ** Generate code for a DELETE FROM statement. ** ** DELETE FROM table_wxyz WHERE a<5 AND b NOT NULL; ** \________/ \________________/ ** pTabList pWhere */ void sqlite3DeleteFrom( Parse *pParse, /* The parser context */ SrcList *pTabList, /* The table from which we should delete things */ Expr *pWhere /* The WHERE clause. May be null */ ){ Vdbe *v; /* The virtual database engine */ Table *pTab; /* The table from which records will be deleted */ const char *zDb; /* Name of database holding pTab */ int end, addr = 0; /* A couple addresses of generated code */ int i; /* Loop counter */ WhereInfo *pWInfo; /* Information about the WHERE clause */ Index *pIdx; /* For looping over indices of the table */ int iCur; /* VDBE Cursor number for pTab */ sqlite3 *db; /* Main database structure */ AuthContext sContext; /* Authorization context */ NameContext sNC; /* Name context to resolve expressions in */ int iDb; /* Database number */ int memCnt = -1; /* Memory cell used for change counting */ int rcauth; /* Value returned by authorization callback */ #ifndef SQLITE_OMIT_TRIGGER int isView; /* True if attempting to delete from a view */ Trigger *pTrigger; /* List of table triggers, if required */ #endif memset(&sContext, 0, sizeof(sContext)); db = pParse->db; if( pParse->nErr || db->mallocFailed ){ goto delete_from_cleanup; } assert( pTabList->nSrc==1 ); /* Locate the table which we want to delete. This table has to be ** put in an SrcList structure because some of the subroutines we ** will be calling are designed to work with multiple tables and expect ** an SrcList* parameter instead of just a Table* parameter. */ pTab = sqlite3SrcListLookup(pParse, pTabList); if( pTab==0 ) goto delete_from_cleanup; /* Figure out if we have any triggers and if the table being ** deleted from is a view */ #ifndef SQLITE_OMIT_TRIGGER pTrigger = sqlite3TriggersExist(pParse, pTab, TK_DELETE, 0, 0); isView = pTab->pSelect!=0; #else # define pTrigger 0 # define isView 0 #endif #ifdef SQLITE_OMIT_VIEW # undef isView # define isView 0 #endif /* If pTab is really a view, make sure it has been initialized. */ if( sqlite3ViewGetColumnNames(pParse, pTab) ){ goto delete_from_cleanup; } if( sqlite3IsReadOnly(pParse, pTab, (pTrigger?1:0)) ){ goto delete_from_cleanup; } iDb = sqlite3SchemaToIndex(db, pTab->pSchema); assert( iDb<db->nDb ); zDb = db->aDb[iDb].zName; rcauth = sqlite3AuthCheck(pParse, SQLITE_DELETE, pTab->zName, 0, zDb); assert( rcauth==SQLITE_OK || rcauth==SQLITE_DENY || rcauth==SQLITE_IGNORE ); if( rcauth==SQLITE_DENY ){ goto delete_from_cleanup; } assert(!isView || pTrigger); /* Assign cursor number to the table and all its indices. */ assert( pTabList->nSrc==1 ); iCur = pTabList->a[0].iCursor = pParse->nTab++; for(pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext){ pParse->nTab++; } /* Start the view context */ if( isView ){ sqlite3AuthContextPush(pParse, &sContext, pTab->zName); } /* Begin generating code. */ v = sqlite3GetVdbe(pParse); if( v==0 ){ goto delete_from_cleanup; } if( pParse->nested==0 ) sqlite3VdbeCountChanges(v); sqlite3BeginWriteOperation(pParse, 1, iDb); /* If we are trying to delete from a view, realize that view into ** a ephemeral table. */ #if !defined(SQLITE_OMIT_VIEW) && !defined(SQLITE_OMIT_TRIGGER) if( isView ){ sqlite3MaterializeView(pParse, pTab, pWhere, iCur); } #endif /* Resolve the column names in the WHERE clause. */ memset(&sNC, 0, sizeof(sNC)); sNC.pParse = pParse; sNC.pSrcList = pTabList; if( sqlite3ResolveExprNames(&sNC, pWhere) ){ goto delete_from_cleanup; } /* Initialize the counter of the number of rows deleted, if ** we are counting rows. */ if( db->flags & SQLITE_CountRows ){ memCnt = ++pParse->nMem; sqlite3VdbeAddOp2(v, OP_Integer, 0, memCnt); } #ifndef SQLITE_OMIT_TRUNCATE_OPTIMIZATION /* Special case: A DELETE without a WHERE clause deletes everything. ** It is easier just to erase the whole table. Prior to version 3.6.5, ** this optimization caused the row change count (the value returned by ** API function sqlite3_count_changes) to be set incorrectly. */ if( rcauth==SQLITE_OK && pWhere==0 && !pTrigger && !IsVirtual(pTab) && 0==sqlite3FkRequired(pParse, pTab, 0, 0) ){ assert( !isView ); sqlite3TableLock(pParse, iDb, pTab->tnum, 1, pTab->zName); sqlite3VdbeAddOp4(v, OP_Clear, pTab->tnum, iDb, memCnt, pTab->zName, P4_STATIC); for(pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext){ assert( pIdx->pSchema==pTab->pSchema ); sqlite3VdbeAddOp2(v, OP_Clear, pIdx->tnum, iDb); } }else #endif /* SQLITE_OMIT_TRUNCATE_OPTIMIZATION */ /* The usual case: There is a WHERE clause so we have to scan through ** the table and pick which records to delete. */ { int iRowSet = ++pParse->nMem; /* Register for rowset of rows to delete */ int iRowid = ++pParse->nMem; /* Used for storing rowid values. */ int regRowid; /* Actual register containing rowids */ /* Collect rowids of every row to be deleted. */ sqlite3VdbeAddOp2(v, OP_Null, 0, iRowSet); pWInfo = sqlite3WhereBegin( pParse, pTabList, pWhere, 0, 0, WHERE_DUPLICATES_OK, 0 ); if( pWInfo==0 ) goto delete_from_cleanup; regRowid = sqlite3ExprCodeGetColumn(pParse, pTab, -1, iCur, iRowid, 0); sqlite3VdbeAddOp2(v, OP_RowSetAdd, iRowSet, regRowid); if( db->flags & SQLITE_CountRows ){ sqlite3VdbeAddOp2(v, OP_AddImm, memCnt, 1); } sqlite3WhereEnd(pWInfo); /* Delete every item whose key was written to the list during the ** database scan. We have to delete items after the scan is complete ** because deleting an item can change the scan order. */ end = sqlite3VdbeMakeLabel(v); /* Unless this is a view, open cursors for the table we are ** deleting from and all its indices. If this is a view, then the ** only effect this statement has is to fire the INSTEAD OF ** triggers. */ if( !isView ){ sqlite3OpenTableAndIndices(pParse, pTab, iCur, OP_OpenWrite); } addr = sqlite3VdbeAddOp3(v, OP_RowSetRead, iRowSet, end, iRowid); /* Delete the row */ #ifndef SQLITE_OMIT_VIRTUALTABLE if( IsVirtual(pTab) ){ const char *pVTab = (const char *)sqlite3GetVTable(db, pTab); sqlite3VtabMakeWritable(pParse, pTab); sqlite3VdbeAddOp4(v, OP_VUpdate, 0, 1, iRowid, pVTab, P4_VTAB); sqlite3VdbeChangeP5(v, OE_Abort); sqlite3MayAbort(pParse); }else #endif { int count = (pParse->nested==0); /* True to count changes */ sqlite3GenerateRowDelete(pParse, pTab, iCur, iRowid, count, pTrigger, OE_Default); } /* End of the delete loop */ sqlite3VdbeAddOp2(v, OP_Goto, 0, addr); sqlite3VdbeResolveLabel(v, end); /* Close the cursors open on the table and its indexes. */ if( !isView && !IsVirtual(pTab) ){ for(i=1, pIdx=pTab->pIndex; pIdx; i++, pIdx=pIdx->pNext){ sqlite3VdbeAddOp2(v, OP_Close, iCur + i, pIdx->tnum); } sqlite3VdbeAddOp1(v, OP_Close, iCur); } } /* Update the sqlite_sequence table by storing the content of the ** maximum rowid counter values recorded while inserting into ** autoincrement tables. */ if( pParse->nested==0 && pParse->pTriggerTab==0 ){ sqlite3AutoincrementEnd(pParse); } /* Return the number of rows that were deleted. If this routine is ** generating code because of a call to sqlite3NestedParse(), do not ** invoke the callback function. */ if( (db->flags&SQLITE_CountRows) && !pParse->nested && !pParse->pTriggerTab ){ sqlite3VdbeAddOp2(v, OP_ResultRow, memCnt, 1); sqlite3VdbeSetNumCols(v, 1); sqlite3VdbeSetColName(v, 0, COLNAME_NAME, "rows deleted", SQLITE_STATIC); } delete_from_cleanup: sqlite3AuthContextPop(&sContext); sqlite3SrcListDelete(db, pTabList); sqlite3ExprDelete(db, pWhere); return; }
/* ** This function is called when inserting, deleting or updating a row of ** table pTab to generate VDBE code to perform foreign key constraint ** processing for the operation. ** ** For a DELETE operation, parameter regOld is passed the index of the ** first register in an array of (pTab->nCol+1) registers containing the ** rowid of the row being deleted, followed by each of the column values ** of the row being deleted, from left to right. Parameter regNew is passed ** zero in this case. ** ** For an INSERT operation, regOld is passed zero and regNew is passed the ** first register of an array of (pTab->nCol+1) registers containing the new ** row data. ** ** For an UPDATE operation, this function is called twice. Once before ** the original record is deleted from the table using the calling convention ** described for DELETE. Then again after the original record is deleted ** but before the new record is inserted using the INSERT convention. */ void sqlite3FkCheck( Parse *pParse, /* Parse context */ Table *pTab, /* Row is being deleted from this table */ int regOld, /* Previous row data is stored here */ int regNew /* New row data is stored here */ ){ sqlite3 *db = pParse->db; /* Database handle */ FKey *pFKey; /* Used to iterate through FKs */ int iDb; /* Index of database containing pTab */ const char *zDb; /* Name of database containing pTab */ int isIgnoreErrors = pParse->disableTriggers; /* Exactly one of regOld and regNew should be non-zero. */ assert( (regOld==0)!=(regNew==0) ); /* If foreign-keys are disabled, this function is a no-op. */ if( (db->flags&SQLITE_ForeignKeys)==0 ) return; iDb = sqlite3SchemaToIndex(db, pTab->pSchema); zDb = db->aDb[iDb].zName; /* Loop through all the foreign key constraints for which pTab is the ** child table (the table that the foreign key definition is part of). */ for(pFKey=pTab->pFKey; pFKey; pFKey=pFKey->pNextFrom){ Table *pTo; /* Parent table of foreign key pFKey */ Index *pIdx = 0; /* Index on key columns in pTo */ int *aiFree = 0; int *aiCol; int iCol; int i; int isIgnore = 0; /* Find the parent table of this foreign key. Also find a unique index ** on the parent key columns in the parent table. If either of these ** schema items cannot be located, set an error in pParse and return ** early. */ if( pParse->disableTriggers ){ pTo = sqlite3FindTable(db, pFKey->zTo, zDb); }else{ pTo = sqlite3LocateTable(pParse, 0, pFKey->zTo, zDb); } if( !pTo || locateFkeyIndex(pParse, pTo, pFKey, &pIdx, &aiFree) ){ assert( isIgnoreErrors==0 || (regOld!=0 && regNew==0) ); if( !isIgnoreErrors || db->mallocFailed ) return; if( pTo==0 ){ /* If isIgnoreErrors is true, then a table is being dropped. In this ** case SQLite runs a "DELETE FROM xxx" on the table being dropped ** before actually dropping it in order to check FK constraints. ** If the parent table of an FK constraint on the current table is ** missing, behave as if it is empty. i.e. decrement the relevant ** FK counter for each row of the current table with non-NULL keys. */ Vdbe *v = sqlite3GetVdbe(pParse); int iJump = sqlite3VdbeCurrentAddr(v) + pFKey->nCol + 1; for(i=0; i<pFKey->nCol; i++){ int iReg = pFKey->aCol[i].iFrom + regOld + 1; sqlite3VdbeAddOp2(v, OP_IsNull, iReg, iJump); } sqlite3VdbeAddOp2(v, OP_FkCounter, pFKey->isDeferred, -1); } continue; } assert( pFKey->nCol==1 || (aiFree && pIdx) ); if( aiFree ){ aiCol = aiFree; }else{ iCol = pFKey->aCol[0].iFrom; aiCol = &iCol; } for(i=0; i<pFKey->nCol; i++){ if( aiCol[i]==pTab->iPKey ){ aiCol[i] = -1; } #ifndef SQLITE_OMIT_AUTHORIZATION /* Request permission to read the parent key columns. If the ** authorization callback returns SQLITE_IGNORE, behave as if any ** values read from the parent table are NULL. */ if( db->xAuth ){ int rcauth; char *zCol = pTo->aCol[pIdx ? pIdx->aiColumn[i] : pTo->iPKey].zName; rcauth = sqlite3AuthReadCol(pParse, pTo->zName, zCol, iDb); isIgnore = (rcauth==SQLITE_IGNORE); } #endif } /* Take a shared-cache advisory read-lock on the parent table. Allocate ** a cursor to use to search the unique index on the parent key columns ** in the parent table. */ sqlite3TableLock(pParse, iDb, pTo->tnum, 0, pTo->zName); pParse->nTab++; if( regOld!=0 ){ /* A row is being removed from the child table. Search for the parent. ** If the parent does not exist, removing the child row resolves an ** outstanding foreign key constraint violation. */ fkLookupParent(pParse, iDb, pTo, pIdx, pFKey, aiCol, regOld, -1,isIgnore); } if( regNew!=0 ){ /* A row is being added to the child table. If a parent row cannot ** be found, adding the child row has violated the FK constraint. */ fkLookupParent(pParse, iDb, pTo, pIdx, pFKey, aiCol, regNew, +1,isIgnore); } sqlite3DbFree(db, aiFree); } /* Loop through all the foreign key constraints that refer to this table */ for(pFKey = sqlite3FkReferences(pTab); pFKey; pFKey=pFKey->pNextTo){ Index *pIdx = 0; /* Foreign key index for pFKey */ SrcList *pSrc; int *aiCol = 0; if( !pFKey->isDeferred && !pParse->pToplevel && !pParse->isMultiWrite ){ assert( regOld==0 && regNew!=0 ); /* Inserting a single row into a parent table cannot cause an immediate ** foreign key violation. So do nothing in this case. */ continue; } if( locateFkeyIndex(pParse, pTab, pFKey, &pIdx, &aiCol) ){ if( !isIgnoreErrors || db->mallocFailed ) return; continue; } assert( aiCol || pFKey->nCol==1 ); /* Create a SrcList structure containing a single table (the table ** the foreign key that refers to this table is attached to). This ** is required for the sqlite3WhereXXX() interface. */ pSrc = sqlite3SrcListAppend(db, 0, 0, 0); if( pSrc ){ struct SrcList_item *pItem = pSrc->a; pItem->pTab = pFKey->pFrom; pItem->zName = pFKey->pFrom->zName; pItem->pTab->nRef++; pItem->iCursor = pParse->nTab++; if( regNew!=0 ){ fkScanChildren(pParse, pSrc, pTab, pIdx, pFKey, aiCol, regNew, -1); } if( regOld!=0 ){ /* If there is a RESTRICT action configured for the current operation ** on the parent table of this FK, then throw an exception ** immediately if the FK constraint is violated, even if this is a ** deferred trigger. That's what RESTRICT means. To defer checking ** the constraint, the FK should specify NO ACTION (represented ** using OE_None). NO ACTION is the default. */ fkScanChildren(pParse, pSrc, pTab, pIdx, pFKey, aiCol, regOld, 1); } pItem->zName = 0; sqlite3SrcListDelete(db, pSrc); } sqlite3DbFree(db, aiCol); } }
/* ** Generate code to do an analysis of all indices associated with ** a single table. */ static void analyzeOneTable( Parse *pParse, /* Parser context */ Table *pTab, /* Table whose indices are to be analyzed */ int iStatCur, /* Cursor that writes to the sqlite_stat1 table */ int iMem /* Available memory locations begin here */ ){ Index *pIdx; /* An index to being analyzed */ int iIdxCur; /* Cursor number for index being analyzed */ int nCol; /* Number of columns in the index */ Vdbe *v; /* The virtual machine being built up */ int i; /* Loop counter */ int topOfLoop; /* The top of the loop */ int endOfLoop; /* The end of the loop */ int addr; /* The address of an instruction */ int iDb; /* Index of database containing pTab */ v = sqlite3GetVdbe(pParse); if( v==0 || pTab==0 || pTab->pIndex==0 ){ /* Do no analysis for tables that have no indices */ return; } assert( sqlite3BtreeHoldsAllMutexes(pParse->db) ); iDb = sqlite3SchemaToIndex(pParse->db, pTab->pSchema); assert( iDb>=0 ); #ifndef SQLITE_OMIT_AUTHORIZATION if( sqlite3AuthCheck(pParse, SQLITE_ANALYZE, pTab->zName, 0, pParse->db->aDb[iDb].zName ) ){ return; } #endif /* Establish a read-lock on the table at the shared-cache level. */ sqlite3TableLock(pParse, iDb, pTab->tnum, 0, pTab->zName); iIdxCur = pParse->nTab; for(pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext){ KeyInfo *pKey = sqlite3IndexKeyinfo(pParse, pIdx); /* Open a cursor to the index to be analyzed */ assert( iDb==sqlite3SchemaToIndex(pParse->db, pIdx->pSchema) ); sqlite3VdbeAddOp(v, OP_Integer, iDb, 0); VdbeComment((v, "# %s", pIdx->zName)); sqlite3VdbeOp3(v, OP_OpenRead, iIdxCur, pIdx->tnum, (char *)pKey, P3_KEYINFO_HANDOFF); nCol = pIdx->nColumn; if( iMem+nCol*2>=pParse->nMem ){ pParse->nMem = iMem+nCol*2+1; } sqlite3VdbeAddOp(v, OP_SetNumColumns, iIdxCur, nCol+1); /* Memory cells are used as follows: ** ** mem[iMem]: The total number of rows in the table. ** mem[iMem+1]: Number of distinct values in column 1 ** ... ** mem[iMem+nCol]: Number of distinct values in column N ** mem[iMem+nCol+1] Last observed value of column 1 ** ... ** mem[iMem+nCol+nCol]: Last observed value of column N ** ** Cells iMem through iMem+nCol are initialized to 0. The others ** are initialized to NULL. */ for(i=0; i<=nCol; i++){ sqlite3VdbeAddOp(v, OP_MemInt, 0, iMem+i); } for(i=0; i<nCol; i++){ sqlite3VdbeAddOp(v, OP_MemNull, iMem+nCol+i+1, 0); } /* Do the analysis. */ endOfLoop = sqlite3VdbeMakeLabel(v); sqlite3VdbeAddOp(v, OP_Rewind, iIdxCur, endOfLoop); topOfLoop = sqlite3VdbeCurrentAddr(v); sqlite3VdbeAddOp(v, OP_MemIncr, 1, iMem); for(i=0; i<nCol; i++){ sqlite3VdbeAddOp(v, OP_Column, iIdxCur, i); sqlite3VdbeAddOp(v, OP_MemLoad, iMem+nCol+i+1, 0); sqlite3VdbeAddOp(v, OP_Ne, 0x100, 0); } sqlite3VdbeAddOp(v, OP_Goto, 0, endOfLoop); for(i=0; i<nCol; i++){ addr = sqlite3VdbeAddOp(v, OP_MemIncr, 1, iMem+i+1); sqlite3VdbeChangeP2(v, topOfLoop + 3*i + 3, addr); sqlite3VdbeAddOp(v, OP_Column, iIdxCur, i); sqlite3VdbeAddOp(v, OP_MemStore, iMem+nCol+i+1, 1); } sqlite3VdbeResolveLabel(v, endOfLoop); sqlite3VdbeAddOp(v, OP_Next, iIdxCur, topOfLoop); sqlite3VdbeAddOp(v, OP_Close, iIdxCur, 0); /* Store the results. ** ** The result is a single row of the sqlite_stat1 table. The first ** two columns are the names of the table and index. The third column ** is a string composed of a list of integer statistics about the ** index. The first integer in the list is the total number of entires ** in the index. There is one additional integer in the list for each ** column of the table. This additional integer is a guess of how many ** rows of the table the index will select. If D is the count of distinct ** values and K is the total number of rows, then the integer is computed ** as: ** ** I = (K+D-1)/D ** ** If K==0 then no entry is made into the sqlite_stat1 table. ** If K>0 then it is always the case the D>0 so division by zero ** is never possible. */ sqlite3VdbeAddOp(v, OP_MemLoad, iMem, 0); addr = sqlite3VdbeAddOp(v, OP_IfNot, 0, 0); sqlite3VdbeAddOp(v, OP_NewRowid, iStatCur, 0); sqlite3VdbeOp3(v, OP_String8, 0, 0, pTab->zName, 0); sqlite3VdbeOp3(v, OP_String8, 0, 0, pIdx->zName, 0); sqlite3VdbeAddOp(v, OP_MemLoad, iMem, 0); sqlite3VdbeOp3(v, OP_String8, 0, 0, " ", 0); for(i=0; i<nCol; i++){ sqlite3VdbeAddOp(v, OP_MemLoad, iMem, 0); sqlite3VdbeAddOp(v, OP_MemLoad, iMem+i+1, 0); sqlite3VdbeAddOp(v, OP_Add, 0, 0); sqlite3VdbeAddOp(v, OP_AddImm, -1, 0); sqlite3VdbeAddOp(v, OP_MemLoad, iMem+i+1, 0); sqlite3VdbeAddOp(v, OP_Divide, 0, 0); sqlite3VdbeAddOp(v, OP_ToInt, 0, 0); if( i==nCol-1 ){ sqlite3VdbeAddOp(v, OP_Concat, nCol*2-1, 0); }else{ sqlite3VdbeAddOp(v, OP_Dup, 1, 0); } } sqlite3VdbeOp3(v, OP_MakeRecord, 3, 0, "aaa", 0); sqlite3VdbeAddOp(v, OP_Insert, iStatCur, OPFLAG_APPEND); sqlite3VdbeJumpHere(v, addr); } }
/* ** This routine generates code that opens the sqlite_stat1 table for ** writing with cursor iStatCur. If the library was built with the ** SQLITE_ENABLE_STAT2 macro defined, then the sqlite_stat2 table is ** opened for writing using cursor (iStatCur+1) ** ** If the sqlite_stat1 tables does not previously exist, it is created. ** Similarly, if the sqlite_stat2 table does not exist and the library ** is compiled with SQLITE_ENABLE_STAT2 defined, it is created. ** ** Argument zWhere may be a pointer to a buffer containing a table name, ** or it may be a NULL pointer. If it is not NULL, then all entries in ** the sqlite_stat1 and (if applicable) sqlite_stat2 tables associated ** with the named table are deleted. If zWhere==0, then code is generated ** to delete all stat table entries. */ static void openStatTable( Parse *pParse, /* Parsing context */ int iDb, /* The database we are looking in */ int iStatCur, /* Open the sqlite_stat1 table on this cursor */ const char *zWhere, /* Delete entries for this table or index */ const char *zWhereType /* Either "tbl" or "idx" */ ){ static const struct { const char *zName; const char *zCols; } aTable[] = { { "sqlite_stat1", "tbl,idx,stat" }, #ifdef SQLITE_ENABLE_STAT2 { "sqlite_stat2", "tbl,idx,sampleno,sample" }, #endif }; int aRoot[] = {0, 0}; u8 aCreateTbl[] = {0, 0}; int i; sqlite3 *db = pParse->db; Db *pDb; Vdbe *v = sqlite3GetVdbe(pParse); if( v==0 ) return; assert( sqlite3BtreeHoldsAllMutexes(db) ); assert( sqlite3VdbeDb(v)==db ); pDb = &db->aDb[iDb]; for(i=0; i<ArraySize(aTable); i++){ const char *zTab = aTable[i].zName; Table *pStat; if( (pStat = sqlite3FindTable(db, zTab, pDb->zName))==0 ){ /* The sqlite_stat[12] table does not exist. Create it. Note that a ** side-effect of the CREATE TABLE statement is to leave the rootpage ** of the new table in register pParse->regRoot. This is important ** because the OpenWrite opcode below will be needing it. */ sqlite3NestedParse(pParse, "CREATE TABLE %Q.%s(%s)", pDb->zName, zTab, aTable[i].zCols ); aRoot[i] = pParse->regRoot; aCreateTbl[i] = 1; }else{ /* The table already exists. If zWhere is not NULL, delete all entries ** associated with the table zWhere. If zWhere is NULL, delete the ** entire contents of the table. */ aRoot[i] = pStat->tnum; sqlite3TableLock(pParse, iDb, aRoot[i], 1, zTab); if( zWhere ){ sqlite3NestedParse(pParse, "DELETE FROM %Q.%s WHERE %s=%Q", pDb->zName, zTab, zWhereType, zWhere ); }else{ /* The sqlite_stat[12] table already exists. Delete all rows. */ sqlite3VdbeAddOp2(v, OP_Clear, aRoot[i], iDb); } } } /* Open the sqlite_stat[12] tables for writing. */ for(i=0; i<ArraySize(aTable); i++){ sqlite3VdbeAddOp3(v, OP_OpenWrite, iStatCur+i, aRoot[i], iDb); sqlite3VdbeChangeP4(v, -1, (char *)3, P4_INT32); sqlite3VdbeChangeP5(v, aCreateTbl[i]); } }
/* ** Generate code to do an analysis of all indices associated with ** a single table. */ static void analyzeOneTable( Parse *pParse, /* Parser context */ Table *pTab, /* Table whose indices are to be analyzed */ Index *pOnlyIdx, /* If not NULL, only analyze this one index */ int iStatCur, /* Index of VdbeCursor that writes the sqlite_stat1 table */ int iMem /* Available memory locations begin here */ ){ sqlite3 *db = pParse->db; /* Database handle */ Index *pIdx; /* An index to being analyzed */ int iIdxCur; /* Cursor open on index being analyzed */ Vdbe *v; /* The virtual machine being built up */ int i; /* Loop counter */ int topOfLoop; /* The top of the loop */ int endOfLoop; /* The end of the loop */ int jZeroRows = -1; /* Jump from here if number of rows is zero */ int iDb; /* Index of database containing pTab */ int regTabname = iMem++; /* Register containing table name */ int regIdxname = iMem++; /* Register containing index name */ int regSampleno = iMem++; /* Register containing next sample number */ int regCol = iMem++; /* Content of a column analyzed table */ int regRec = iMem++; /* Register holding completed record */ int regTemp = iMem++; /* Temporary use register */ int regRowid = iMem++; /* Rowid for the inserted record */ #ifdef SQLITE_ENABLE_STAT2 int addr = 0; /* Instruction address */ int regTemp2 = iMem++; /* Temporary use register */ int regSamplerecno = iMem++; /* Index of next sample to record */ int regRecno = iMem++; /* Current sample index */ int regLast = iMem++; /* Index of last sample to record */ int regFirst = iMem++; /* Index of first sample to record */ #endif v = sqlite3GetVdbe(pParse); if( v==0 || NEVER(pTab==0) ){ return; } if( pTab->tnum==0 ){ /* Do not gather statistics on views or virtual tables */ return; } if( memcmp(pTab->zName, "sqlite_", 7)==0 ){ /* Do not gather statistics on system tables */ return; } assert( sqlite3BtreeHoldsAllMutexes(db) ); iDb = sqlite3SchemaToIndex(db, pTab->pSchema); assert( iDb>=0 ); assert( sqlite3SchemaMutexHeld(db, iDb, 0) ); #ifndef SQLITE_OMIT_AUTHORIZATION if( sqlite3AuthCheck(pParse, SQLITE_ANALYZE, pTab->zName, 0, db->aDb[iDb].zName ) ){ return; } #endif /* Establish a read-lock on the table at the shared-cache level. */ sqlite3TableLock(pParse, iDb, pTab->tnum, 0, pTab->zName); iIdxCur = pParse->nTab++; sqlite3VdbeAddOp4(v, OP_String8, 0, regTabname, 0, pTab->zName, 0); for(pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext){ int nCol; KeyInfo *pKey; if( pOnlyIdx && pOnlyIdx!=pIdx ) continue; nCol = pIdx->nColumn; pKey = sqlite3IndexKeyinfo(pParse, pIdx); if( iMem+1+(nCol*2)>pParse->nMem ){ pParse->nMem = iMem+1+(nCol*2); } /* Open a cursor to the index to be analyzed. */ assert( iDb==sqlite3SchemaToIndex(db, pIdx->pSchema) ); sqlite3VdbeAddOp4(v, OP_OpenRead, iIdxCur, pIdx->tnum, iDb, (char *)pKey, P4_KEYINFO_HANDOFF); VdbeComment((v, "%s", pIdx->zName)); /* Populate the register containing the index name. */ sqlite3VdbeAddOp4(v, OP_String8, 0, regIdxname, 0, pIdx->zName, 0); #ifdef SQLITE_ENABLE_STAT2 /* If this iteration of the loop is generating code to analyze the ** first index in the pTab->pIndex list, then register regLast has ** not been populated. In this case populate it now. */ if( pTab->pIndex==pIdx ){ sqlite3VdbeAddOp2(v, OP_Integer, SQLITE_INDEX_SAMPLES, regSamplerecno); sqlite3VdbeAddOp2(v, OP_Integer, SQLITE_INDEX_SAMPLES*2-1, regTemp); sqlite3VdbeAddOp2(v, OP_Integer, SQLITE_INDEX_SAMPLES*2, regTemp2); sqlite3VdbeAddOp2(v, OP_Count, iIdxCur, regLast); sqlite3VdbeAddOp2(v, OP_Null, 0, regFirst); addr = sqlite3VdbeAddOp3(v, OP_Lt, regSamplerecno, 0, regLast); sqlite3VdbeAddOp3(v, OP_Divide, regTemp2, regLast, regFirst); sqlite3VdbeAddOp3(v, OP_Multiply, regLast, regTemp, regLast); sqlite3VdbeAddOp2(v, OP_AddImm, regLast, SQLITE_INDEX_SAMPLES*2-2); sqlite3VdbeAddOp3(v, OP_Divide, regTemp2, regLast, regLast); sqlite3VdbeJumpHere(v, addr); } /* Zero the regSampleno and regRecno registers. */ sqlite3VdbeAddOp2(v, OP_Integer, 0, regSampleno); sqlite3VdbeAddOp2(v, OP_Integer, 0, regRecno); sqlite3VdbeAddOp2(v, OP_Copy, regFirst, regSamplerecno); #endif /* The block of memory cells initialized here is used as follows. ** ** iMem: ** The total number of rows in the table. ** ** iMem+1 .. iMem+nCol: ** Number of distinct entries in index considering the ** left-most N columns only, where N is between 1 and nCol, ** inclusive. ** ** iMem+nCol+1 .. Mem+2*nCol: ** Previous value of indexed columns, from left to right. ** ** Cells iMem through iMem+nCol are initialized to 0. The others are ** initialized to contain an SQL NULL. */ for(i=0; i<=nCol; i++){ sqlite3VdbeAddOp2(v, OP_Integer, 0, iMem+i); } for(i=0; i<nCol; i++){ sqlite3VdbeAddOp2(v, OP_Null, 0, iMem+nCol+i+1); } /* Start the analysis loop. This loop runs through all the entries in ** the index b-tree. */ endOfLoop = sqlite3VdbeMakeLabel(v); sqlite3VdbeAddOp2(v, OP_Rewind, iIdxCur, endOfLoop); topOfLoop = sqlite3VdbeCurrentAddr(v); sqlite3VdbeAddOp2(v, OP_AddImm, iMem, 1); for(i=0; i<nCol; i++){ CollSeq *pColl; sqlite3VdbeAddOp3(v, OP_Column, iIdxCur, i, regCol); if( i==0 ){ #ifdef SQLITE_ENABLE_STAT2 /* Check if the record that cursor iIdxCur points to contains a ** value that should be stored in the sqlite_stat2 table. If so, ** store it. */ int ne = sqlite3VdbeAddOp3(v, OP_Ne, regRecno, 0, regSamplerecno); assert( regTabname+1==regIdxname && regTabname+2==regSampleno && regTabname+3==regCol ); sqlite3VdbeChangeP5(v, SQLITE_JUMPIFNULL); sqlite3VdbeAddOp4(v, OP_MakeRecord, regTabname, 4, regRec, "aaab", 0); sqlite3VdbeAddOp2(v, OP_NewRowid, iStatCur+1, regRowid); sqlite3VdbeAddOp3(v, OP_Insert, iStatCur+1, regRec, regRowid); /* Calculate new values for regSamplerecno and regSampleno. ** ** sampleno = sampleno + 1 ** samplerecno = samplerecno+(remaining records)/(remaining samples) */ sqlite3VdbeAddOp2(v, OP_AddImm, regSampleno, 1); sqlite3VdbeAddOp3(v, OP_Subtract, regRecno, regLast, regTemp); sqlite3VdbeAddOp2(v, OP_AddImm, regTemp, -1); sqlite3VdbeAddOp2(v, OP_Integer, SQLITE_INDEX_SAMPLES, regTemp2); sqlite3VdbeAddOp3(v, OP_Subtract, regSampleno, regTemp2, regTemp2); sqlite3VdbeAddOp3(v, OP_Divide, regTemp2, regTemp, regTemp); sqlite3VdbeAddOp3(v, OP_Add, regSamplerecno, regTemp, regSamplerecno); sqlite3VdbeJumpHere(v, ne); sqlite3VdbeAddOp2(v, OP_AddImm, regRecno, 1); #endif /* Always record the very first row */ sqlite3VdbeAddOp1(v, OP_IfNot, iMem+1); } assert( pIdx->azColl!=0 ); assert( pIdx->azColl[i]!=0 ); pColl = sqlite3LocateCollSeq(pParse, pIdx->azColl[i]); sqlite3VdbeAddOp4(v, OP_Ne, regCol, 0, iMem+nCol+i+1, (char*)pColl, P4_COLLSEQ); sqlite3VdbeChangeP5(v, SQLITE_NULLEQ); } if( db->mallocFailed ){ /* If a malloc failure has occurred, then the result of the expression ** passed as the second argument to the call to sqlite3VdbeJumpHere() ** below may be negative. Which causes an assert() to fail (or an ** out-of-bounds write if SQLITE_DEBUG is not defined). */ return; } sqlite3VdbeAddOp2(v, OP_Goto, 0, endOfLoop); for(i=0; i<nCol; i++){ int addr2 = sqlite3VdbeCurrentAddr(v) - (nCol*2); if( i==0 ){ sqlite3VdbeJumpHere(v, addr2-1); /* Set jump dest for the OP_IfNot */ } sqlite3VdbeJumpHere(v, addr2); /* Set jump dest for the OP_Ne */ sqlite3VdbeAddOp2(v, OP_AddImm, iMem+i+1, 1); sqlite3VdbeAddOp3(v, OP_Column, iIdxCur, i, iMem+nCol+i+1); } /* End of the analysis loop. */ sqlite3VdbeResolveLabel(v, endOfLoop); sqlite3VdbeAddOp2(v, OP_Next, iIdxCur, topOfLoop); sqlite3VdbeAddOp1(v, OP_Close, iIdxCur); /* Store the results in sqlite_stat1. ** ** The result is a single row of the sqlite_stat1 table. The first ** two columns are the names of the table and index. The third column ** is a string composed of a list of integer statistics about the ** index. The first integer in the list is the total number of entries ** in the index. There is one additional integer in the list for each ** column of the table. This additional integer is a guess of how many ** rows of the table the index will select. If D is the count of distinct ** values and K is the total number of rows, then the integer is computed ** as: ** ** I = (K+D-1)/D ** ** If K==0 then no entry is made into the sqlite_stat1 table. ** If K>0 then it is always the case the D>0 so division by zero ** is never possible. */ sqlite3VdbeAddOp2(v, OP_SCopy, iMem, regSampleno); if( jZeroRows<0 ){ jZeroRows = sqlite3VdbeAddOp1(v, OP_IfNot, iMem); } for(i=0; i<nCol; i++){ sqlite3VdbeAddOp4(v, OP_String8, 0, regTemp, 0, " ", 0); sqlite3VdbeAddOp3(v, OP_Concat, regTemp, regSampleno, regSampleno); sqlite3VdbeAddOp3(v, OP_Add, iMem, iMem+i+1, regTemp); sqlite3VdbeAddOp2(v, OP_AddImm, regTemp, -1); sqlite3VdbeAddOp3(v, OP_Divide, iMem+i+1, regTemp, regTemp); sqlite3VdbeAddOp1(v, OP_ToInt, regTemp); sqlite3VdbeAddOp3(v, OP_Concat, regTemp, regSampleno, regSampleno); } sqlite3VdbeAddOp4(v, OP_MakeRecord, regTabname, 3, regRec, "aaa", 0); sqlite3VdbeAddOp2(v, OP_NewRowid, iStatCur, regRowid); sqlite3VdbeAddOp3(v, OP_Insert, iStatCur, regRec, regRowid); sqlite3VdbeChangeP5(v, OPFLAG_APPEND); } /* If the table has no indices, create a single sqlite_stat1 entry ** containing NULL as the index name and the row count as the content. */ if( pTab->pIndex==0 ){ sqlite3VdbeAddOp3(v, OP_OpenRead, iIdxCur, pTab->tnum, iDb); VdbeComment((v, "%s", pTab->zName)); sqlite3VdbeAddOp2(v, OP_Count, iIdxCur, regSampleno); sqlite3VdbeAddOp1(v, OP_Close, iIdxCur); jZeroRows = sqlite3VdbeAddOp1(v, OP_IfNot, regSampleno); }else{ sqlite3VdbeJumpHere(v, jZeroRows); jZeroRows = sqlite3VdbeAddOp0(v, OP_Goto); } sqlite3VdbeAddOp2(v, OP_Null, 0, regIdxname); sqlite3VdbeAddOp4(v, OP_MakeRecord, regTabname, 3, regRec, "aaa", 0); sqlite3VdbeAddOp2(v, OP_NewRowid, iStatCur, regRowid); sqlite3VdbeAddOp3(v, OP_Insert, iStatCur, regRec, regRowid); sqlite3VdbeChangeP5(v, OPFLAG_APPEND); if( pParse->nMem<regRec ) pParse->nMem = regRec; sqlite3VdbeJumpHere(v, jZeroRows); }