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Overview
Comment: | Slight simplification to the query optimizer logic associated with IN (SELECT). |
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Downloads: | Tarball | ZIP archive |
Timelines: | family | ancestors | descendants | both | trunk |
Files: | files | file ages | folders |
SHA1: |
2c55c3c2950cafdc256ab540f60dc460 |
User & Date: | drh 2016-03-09 15:34:51.959 |
Context
2016-03-09
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18:17 | Fix a problem in fts3/4 that was causing it to discard data cached in-memory if an 'optimize' command is run when there is no data on disk. The usual way this would happen is if the very first transaction that writes to the fts3/4 table also includes an 'optimize' command. (check-in: 79338b991b user: dan tags: trunk) | |
15:34 | Slight simplification to the query optimizer logic associated with IN (SELECT). (check-in: 2c55c3c295 user: drh tags: trunk) | |
15:14 | Add another test case for bug [5e3c8867]. (check-in: d91e57e49f user: dan tags: trunk) | |
Changes
Changes to src/expr.c.
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1564 1565 1566 1567 1568 1569 1570 | if( sqlite3StrICmp(z, "_ROWID_")==0 ) return 1; if( sqlite3StrICmp(z, "ROWID")==0 ) return 1; if( sqlite3StrICmp(z, "OID")==0 ) return 1; return 0; } /* | | | < | < | | < < < | > > < | > > | | | | 1564 1565 1566 1567 1568 1569 1570 1571 1572 1573 1574 1575 1576 1577 1578 1579 1580 1581 1582 1583 1584 1585 1586 1587 1588 1589 1590 1591 1592 1593 1594 1595 1596 1597 1598 1599 1600 1601 1602 1603 1604 1605 1606 1607 1608 1609 1610 1611 1612 1613 1614 1615 1616 1617 | if( sqlite3StrICmp(z, "_ROWID_")==0 ) return 1; if( sqlite3StrICmp(z, "ROWID")==0 ) return 1; if( sqlite3StrICmp(z, "OID")==0 ) return 1; return 0; } /* ** pX is the RHS of an IN operator. If pX is a SELECT statement ** that can be simplified to a direct table access, then return ** a pointer to the SELECT statement. If pX is not a SELECT statement, ** or if the SELECT statement needs to be manifested into a transient ** table, then return NULL. */ #ifndef SQLITE_OMIT_SUBQUERY static Select *isCandidateForInOpt(Expr *pX){ Select *p; SrcList *pSrc; ExprList *pEList; Expr *pRes; Table *pTab; if( !ExprHasProperty(pX, EP_xIsSelect) ) return 0; /* Not a subquery */ if( ExprHasProperty(pX, EP_VarSelect) ) return 0; /* Correlated subq */ p = pX->x.pSelect; if( p->pPrior ) return 0; /* Not a compound SELECT */ if( p->selFlags & (SF_Distinct|SF_Aggregate) ){ testcase( (p->selFlags & (SF_Distinct|SF_Aggregate))==SF_Distinct ); testcase( (p->selFlags & (SF_Distinct|SF_Aggregate))==SF_Aggregate ); return 0; /* No DISTINCT keyword and no aggregate functions */ } assert( p->pGroupBy==0 ); /* Has no GROUP BY clause */ if( p->pLimit ) return 0; /* Has no LIMIT clause */ assert( p->pOffset==0 ); /* No LIMIT means no OFFSET */ if( p->pWhere ) return 0; /* Has no WHERE clause */ pSrc = p->pSrc; assert( pSrc!=0 ); if( pSrc->nSrc!=1 ) return 0; /* Single term in FROM clause */ if( pSrc->a[0].pSelect ) return 0; /* FROM is not a subquery or view */ pTab = pSrc->a[0].pTab; assert( pTab!=0 ); assert( pTab->pSelect==0 ); /* FROM clause is not a view */ if( IsVirtual(pTab) ) return 0; /* FROM clause not a virtual table */ pEList = p->pEList; if( pEList->nExpr!=1 ) return 0; /* One column in the result set */ pRes = pEList->a[0].pExpr; if( pRes->op!=TK_COLUMN ) return 0; /* Result is a column */ assert( pRes->iTable==pSrc->a[0].iCursor ); /* Not a correlated subquery */ return p; } #endif /* SQLITE_OMIT_SUBQUERY */ /* ** Code an OP_Once instruction and allocate space for its flag. Return the ** address of the new instruction. */ |
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1737 1738 1739 1740 1741 1742 1743 | assert( pX->op==TK_IN ); mustBeUnique = (inFlags & IN_INDEX_LOOP)!=0; /* Check to see if an existing table or index can be used to ** satisfy the query. This is preferable to generating a new ** ephemeral table. */ | < | < | 1735 1736 1737 1738 1739 1740 1741 1742 1743 1744 1745 1746 1747 1748 1749 1750 1751 1752 1753 1754 1755 | assert( pX->op==TK_IN ); mustBeUnique = (inFlags & IN_INDEX_LOOP)!=0; /* Check to see if an existing table or index can be used to ** satisfy the query. This is preferable to generating a new ** ephemeral table. */ if( pParse->nErr==0 && (p = isCandidateForInOpt(pX))!=0 ){ sqlite3 *db = pParse->db; /* Database connection */ Table *pTab; /* Table <table>. */ Expr *pExpr; /* Expression <column> */ i16 iCol; /* Index of column <column> */ i16 iDb; /* Database idx for pTab */ assert( p->pEList!=0 ); /* Because of isCandidateForInOpt(p) */ assert( p->pEList->a[0].pExpr!=0 ); /* Because of isCandidateForInOpt(p) */ assert( p->pSrc!=0 ); /* Because of isCandidateForInOpt(p) */ pTab = p->pSrc->a[0].pTab; pExpr = p->pEList->a[0].pExpr; iCol = (i16)pExpr->iColumn; |
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