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Overview
| Comment: | Improved comments. Fix a problem when an indexed expression is used in an ORDER BY clause. |
|---|---|
| Downloads: | Tarball | ZIP archive | SQL archive |
| Timelines: | family | ancestors | descendants | both | covering-index-on-expr |
| Files: | files | file ages | folders |
| SHA3-256: |
c59eaf2b7cd2596733f349fc0fe979f7 |
| User & Date: | drh 2017-04-11 01:01:27 |
Context
|
2017-04-11
| ||
| 01:30 | When evaluating a query that uses an index on an expression, try to use the expression values read directly from the index rather than reevaluating the expression. check-in: a47efb7c user: drh tags: trunk | |
| 01:01 | Improved comments. Fix a problem when an indexed expression is used in an ORDER BY clause. Closed-Leaf check-in: c59eaf2b user: drh tags: covering-index-on-expr | |
|
2017-04-10
| ||
| 23:42 | Merge changes from trunk. check-in: 8978465f user: drh tags: covering-index-on-expr | |
Changes
Changes to src/select.c.
1526 1527 1528 1529 1530 1531 1532 1533 1534 1535 1536 1537 1538 1539 .... 1549 1550 1551 1552 1553 1554 1555 1556 1557 1558 1559 1560 1561 1562 1563 1564 1565 1566 1567 1568 1569 1570 1571 1572 1573 1574 1575 .... 1586 1587 1588 1589 1590 1591 1592 1593 1594 1595 1596 1597 1598 1599 1600 1601 1602 1603 1604 1605 1606 1607 1608 |
){
#ifndef SQLITE_OMIT_DECLTYPE
Vdbe *v = pParse->pVdbe;
int i;
NameContext sNC;
sNC.pSrcList = pTabList;
sNC.pParse = pParse;
for(i=0; i<pEList->nExpr; i++){
Expr *p = pEList->a[i].pExpr;
const char *zType;
#ifdef SQLITE_ENABLE_COLUMN_METADATA
const char *zOrigDb = 0;
const char *zOrigTab = 0;
const char *zOrigCol = 0;
................................................................................
#else
zType = columnType(&sNC, p, 0, 0, 0, 0);
#endif
sqlite3VdbeSetColName(v, i, COLNAME_DECLTYPE, zType, SQLITE_TRANSIENT);
}
#endif /* !defined(SQLITE_OMIT_DECLTYPE) */
}
/*
** Generate code that will tell the VDBE the names of columns
** in the result set. This information is used to provide the
** azCol[] values in the callback.
*/
static void generateColumnNames(
Parse *pParse, /* Parser context */
SrcList *pTabList, /* List of tables */
ExprList *pEList /* Expressions defining the result set */
){
Vdbe *v = pParse->pVdbe;
int i, j;
sqlite3 *db = pParse->db;
int fullNames, shortNames;
#ifndef SQLITE_OMIT_EXPLAIN
/* If this is an EXPLAIN, skip this step */
if( pParse->explain ){
return;
................................................................................
for(i=0; i<pEList->nExpr; i++){
Expr *p;
p = pEList->a[i].pExpr;
if( NEVER(p==0) ) continue;
if( pEList->a[i].zName ){
char *zName = pEList->a[i].zName;
sqlite3VdbeSetColName(v, i, COLNAME_NAME, zName, SQLITE_TRANSIENT);
}else if( p->op==TK_COLUMN || p->op==TK_AGG_COLUMN ){
Table *pTab;
char *zCol;
int iCol = p->iColumn;
for(j=0; ALWAYS(j<pTabList->nSrc); j++){
if( pTabList->a[j].iCursor==p->iTable ) break;
}
assert( j<pTabList->nSrc );
pTab = pTabList->a[j].pTab;
if( iCol<0 ) iCol = pTab->iPKey;
assert( iCol==-1 || (iCol>=0 && iCol<pTab->nCol) );
if( iCol<0 ){
zCol = "rowid";
}else{
zCol = pTab->aCol[iCol].zName;
}
|
> > > > > > > > > > > > > > | > | | > < < < < < |
1526 1527 1528 1529 1530 1531 1532 1533 1534 1535 1536 1537 1538 1539 1540 .... 1550 1551 1552 1553 1554 1555 1556 1557 1558 1559 1560 1561 1562 1563 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 .... 1601 1602 1603 1604 1605 1606 1607 1608 1609 1610 1611 1612 1613 1614 1615 1616 1617 1618 1619 |
){
#ifndef SQLITE_OMIT_DECLTYPE
Vdbe *v = pParse->pVdbe;
int i;
NameContext sNC;
sNC.pSrcList = pTabList;
sNC.pParse = pParse;
sNC.pNext = 0;
for(i=0; i<pEList->nExpr; i++){
Expr *p = pEList->a[i].pExpr;
const char *zType;
#ifdef SQLITE_ENABLE_COLUMN_METADATA
const char *zOrigDb = 0;
const char *zOrigTab = 0;
const char *zOrigCol = 0;
................................................................................
#else
zType = columnType(&sNC, p, 0, 0, 0, 0);
#endif
sqlite3VdbeSetColName(v, i, COLNAME_DECLTYPE, zType, SQLITE_TRANSIENT);
}
#endif /* !defined(SQLITE_OMIT_DECLTYPE) */
}
/*
** Return the Table objecct in the SrcList that has cursor iCursor.
** Or return NULL if no such Table object exists in the SrcList.
*/
static Table *tableWithCursor(SrcList *pList, int iCursor){
int j;
for(j=0; j<pList->nSrc; j++){
if( pList->a[j].iCursor==iCursor ) return pList->a[j].pTab;
}
return 0;
}
/*
** Generate code that will tell the VDBE the names of columns
** in the result set. This information is used to provide the
** azCol[] values in the callback.
*/
static void generateColumnNames(
Parse *pParse, /* Parser context */
SrcList *pTabList, /* List of tables */
ExprList *pEList /* Expressions defining the result set */
){
Vdbe *v = pParse->pVdbe;
int i;
Table *pTab;
sqlite3 *db = pParse->db;
int fullNames, shortNames;
#ifndef SQLITE_OMIT_EXPLAIN
/* If this is an EXPLAIN, skip this step */
if( pParse->explain ){
return;
................................................................................
for(i=0; i<pEList->nExpr; i++){
Expr *p;
p = pEList->a[i].pExpr;
if( NEVER(p==0) ) continue;
if( pEList->a[i].zName ){
char *zName = pEList->a[i].zName;
sqlite3VdbeSetColName(v, i, COLNAME_NAME, zName, SQLITE_TRANSIENT);
}else if( (p->op==TK_COLUMN || p->op==TK_AGG_COLUMN)
&& (pTab = tableWithCursor(pTabList, p->iTable))!=0
){
char *zCol;
int iCol = p->iColumn;
if( iCol<0 ) iCol = pTab->iPKey;
assert( iCol==-1 || (iCol>=0 && iCol<pTab->nCol) );
if( iCol<0 ){
zCol = "rowid";
}else{
zCol = pTab->aCol[iCol].zName;
}
|
Changes to src/wherecode.c.
1035 1036 1037 1038 1039 1040 1041 1042 1043 1044 1045 1046 1047 1048 1049 1050 1051 1052 1053 1054 1055 1056 .... 1088 1089 1090 1091 1092 1093 1094 1095 1096 1097 1098 1099 1100 1101 1102 .... 1671 1672 1673 1674 1675 1676 1677 1678 1679 1680 1681 1682 1683 1684 1685 1686 1687 |
}
}else{
assert( nReg==1 );
sqlite3ExprCode(pParse, p, iReg);
}
}
#if 1 /* INDEXEXPRTRANS */
typedef struct IdxExprTrans {
Expr *pIdxExpr; /* The index expression */
int iTabCur; /* The cursor of the corresponding table */
int iIdxCur; /* The cursor for the index */
int iIdxCol; /* The column for the index */
} IdxExprTrans;
static int whereIndexExprTransNode(Walker *p, Expr *pExpr){
IdxExprTrans *pX = p->u.pIdxTrans;
if( sqlite3ExprCompare(pExpr, pX->pIdxExpr, pX->iTabCur)==0 ){
pExpr->op = TK_COLUMN;
pExpr->iTable = pX->iIdxCur;
pExpr->iColumn = pX->iIdxCol;
pExpr->pTab = 0;
................................................................................
x.iIdxCol = iIdxCol;
x.pIdxExpr = aColExpr->a[iIdxCol].pExpr;
sqlite3WalkExpr(&w, pWInfo->pWhere);
sqlite3WalkExprList(&w, pWInfo->pOrderBy);
sqlite3WalkExprList(&w, pWInfo->pResultSet);
}
}
#endif
/*
** Generate code for the start of the iLevel-th loop in the WHERE clause
** implementation described by pWInfo.
*/
Bitmask sqlite3WhereCodeOneLoopStart(
WhereInfo *pWInfo, /* Complete information about the WHERE clause */
................................................................................
k = sqlite3ColumnOfIndex(pIdx, pPk->aiColumn[j]);
sqlite3VdbeAddOp3(v, OP_Column, iIdxCur, k, iRowidReg+j);
}
sqlite3VdbeAddOp4Int(v, OP_NotFound, iCur, addrCont,
iRowidReg, pPk->nKeyCol); VdbeCoverage(v);
}
#if 1 /* INDEXEXPRTANS */
whereIndexExprTrans(pIdx, iCur, iIdxCur, pWInfo);
#endif
/* Record the instruction used to terminate the loop. */
if( pLoop->wsFlags & WHERE_ONEROW ){
pLevel->op = OP_Noop;
}else if( bRev ){
pLevel->op = OP_Prev;
}else{
|
| > > > > > > > > > < | > > > < > |
1035 1036 1037 1038 1039 1040 1041 1042 1043 1044 1045 1046 1047 1048 1049 1050 1051 1052 1053 1054 1055 1056 1057 1058 1059 1060 1061 1062 1063 1064 1065 .... 1097 1098 1099 1100 1101 1102 1103 1104 1105 1106 1107 1108 1109 1110 .... 1679 1680 1681 1682 1683 1684 1685 1686 1687 1688 1689 1690 1691 1692 1693 1694 1695 1696 1697 1698 |
}
}else{
assert( nReg==1 );
sqlite3ExprCode(pParse, p, iReg);
}
}
/* An instance of the IdxExprTrans object carries information about a
** mapping from an expression on table columns into a column in an index
** down through the Walker.
*/
typedef struct IdxExprTrans {
Expr *pIdxExpr; /* The index expression */
int iTabCur; /* The cursor of the corresponding table */
int iIdxCur; /* The cursor for the index */
int iIdxCol; /* The column for the index */
} IdxExprTrans;
/* The walker node callback used to transform matching expressions into
** a reference to an index column for an index on an expression.
**
** If pExpr matches, then transform it into a reference to the index column
** that contains the value of pExpr.
*/
static int whereIndexExprTransNode(Walker *p, Expr *pExpr){
IdxExprTrans *pX = p->u.pIdxTrans;
if( sqlite3ExprCompare(pExpr, pX->pIdxExpr, pX->iTabCur)==0 ){
pExpr->op = TK_COLUMN;
pExpr->iTable = pX->iIdxCur;
pExpr->iColumn = pX->iIdxCol;
pExpr->pTab = 0;
................................................................................
x.iIdxCol = iIdxCol;
x.pIdxExpr = aColExpr->a[iIdxCol].pExpr;
sqlite3WalkExpr(&w, pWInfo->pWhere);
sqlite3WalkExprList(&w, pWInfo->pOrderBy);
sqlite3WalkExprList(&w, pWInfo->pResultSet);
}
}
/*
** Generate code for the start of the iLevel-th loop in the WHERE clause
** implementation described by pWInfo.
*/
Bitmask sqlite3WhereCodeOneLoopStart(
WhereInfo *pWInfo, /* Complete information about the WHERE clause */
................................................................................
k = sqlite3ColumnOfIndex(pIdx, pPk->aiColumn[j]);
sqlite3VdbeAddOp3(v, OP_Column, iIdxCur, k, iRowidReg+j);
}
sqlite3VdbeAddOp4Int(v, OP_NotFound, iCur, addrCont,
iRowidReg, pPk->nKeyCol); VdbeCoverage(v);
}
/* If pIdx is an index on one or more expressions, then look through
** all the expressions in pWInfo and try to transform matching expressions
** into reference to index columns.
*/
whereIndexExprTrans(pIdx, iCur, iIdxCur, pWInfo);
/* Record the instruction used to terminate the loop. */
if( pLoop->wsFlags & WHERE_ONEROW ){
pLevel->op = OP_Noop;
}else if( bRev ){
pLevel->op = OP_Prev;
}else{
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