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Overview
| Comment: | Enhance the query planner so that it is able to use indexed expressions to help fulfill an ORDER BY clause. |
|---|---|
| Downloads: | Tarball | ZIP archive | SQL archive |
| Timelines: | family | ancestors | descendants | both | trunk |
| Files: | files | file ages | folders |
| SHA1: |
668fc1ebaf426f9eed3ed7865e41f102 |
| User & Date: | drh 2015-09-24 18:47:59 |
Context
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2015-09-25
| ||
| 01:09 | Fix a problem computing affinities for indexes during skip-scan code generation when SQLITE_ENABLE_STAT4 is on. Bug introduced by check-in [1ee089a72d789002]. (check-in: 1350dd42 user: drh tags: trunk) | |
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2015-09-24
| ||
| 18:47 | Enhance the query planner so that it is able to use indexed expressions to help fulfill an ORDER BY clause. (check-in: 668fc1eb user: drh tags: trunk) | |
| 17:38 | Fix over-length source code lines in where.c. No logic changes. (check-in: 1c8c5380 user: drh tags: trunk) | |
Changes
Changes to src/where.c.
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*/
static int indexMightHelpWithOrderBy(
WhereLoopBuilder *pBuilder,
Index *pIndex,
int iCursor
){
ExprList *pOB;
int ii, jj;
if( pIndex->bUnordered ) return 0;
if( (pOB = pBuilder->pWInfo->pOrderBy)==0 ) return 0;
for(ii=0; ii<pOB->nExpr; ii++){
Expr *pExpr = sqlite3ExprSkipCollate(pOB->a[ii].pExpr);
if( pExpr->op!=TK_COLUMN ) return 0;
if( pExpr->iTable==iCursor ){
if( pExpr->iColumn<0 ) return 1;
for(jj=0; jj<pIndex->nKeyCol; jj++){
if( pExpr->iColumn==pIndex->aiColumn[jj] ) return 1;
}
}
}
return 0;
}
/*
................................................................................
isMatch = 0;
for(i=0; bOnce && i<nOrderBy; i++){
if( MASKBIT(i) & obSat ) continue;
pOBExpr = sqlite3ExprSkipCollate(pOrderBy->a[i].pExpr);
testcase( wctrlFlags & WHERE_GROUPBY );
testcase( wctrlFlags & WHERE_DISTINCTBY );
if( (wctrlFlags & (WHERE_GROUPBY|WHERE_DISTINCTBY))==0 ) bOnce = 0;
if( pOBExpr->op!=TK_COLUMN ) continue;
if( pOBExpr->iTable!=iCur ) continue;
if( pOBExpr->iColumn!=iColumn ) continue;
if( iColumn>=0 ){
pColl = sqlite3ExprCollSeq(pWInfo->pParse, pOrderBy->a[i].pExpr);
if( !pColl ) pColl = db->pDfltColl;
if( sqlite3StrICmp(pColl->zName, pIndex->azColl[j])!=0 ) continue;
}
isMatch = 1;
break;
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*/
static int indexMightHelpWithOrderBy(
WhereLoopBuilder *pBuilder,
Index *pIndex,
int iCursor
){
ExprList *pOB;
ExprList *aColExpr;
int ii, jj;
if( pIndex->bUnordered ) return 0;
if( (pOB = pBuilder->pWInfo->pOrderBy)==0 ) return 0;
for(ii=0; ii<pOB->nExpr; ii++){
Expr *pExpr = sqlite3ExprSkipCollate(pOB->a[ii].pExpr);
if( pExpr->op==TK_COLUMN && pExpr->iTable==iCursor ){
if( pExpr->iColumn<0 ) return 1;
for(jj=0; jj<pIndex->nKeyCol; jj++){
if( pExpr->iColumn==pIndex->aiColumn[jj] ) return 1;
}
}else if( (aColExpr = pIndex->aColExpr)!=0 ){
for(jj=0; jj<pIndex->nKeyCol; jj++){
if( pIndex->aiColumn[jj]!=(-2) ) continue;
if( sqlite3ExprCompare(pExpr,aColExpr->a[jj].pExpr,iCursor)==0 ){
return 1;
}
}
}
}
return 0;
}
/*
................................................................................
isMatch = 0;
for(i=0; bOnce && i<nOrderBy; i++){
if( MASKBIT(i) & obSat ) continue;
pOBExpr = sqlite3ExprSkipCollate(pOrderBy->a[i].pExpr);
testcase( wctrlFlags & WHERE_GROUPBY );
testcase( wctrlFlags & WHERE_DISTINCTBY );
if( (wctrlFlags & (WHERE_GROUPBY|WHERE_DISTINCTBY))==0 ) bOnce = 0;
if( iColumn>=(-1) ){
if( pOBExpr->op!=TK_COLUMN ) continue;
if( pOBExpr->iTable!=iCur ) continue;
if( pOBExpr->iColumn!=iColumn ) continue;
}else{
if( sqlite3ExprCompare(pOBExpr,pIndex->aColExpr->a[j].pExpr,iCur) ){
continue;
}
}
if( iColumn>=0 ){
pColl = sqlite3ExprCollSeq(pWInfo->pParse, pOrderBy->a[i].pExpr);
if( !pColl ) pColl = db->pDfltColl;
if( sqlite3StrICmp(pColl->zName, pIndex->azColl[j])!=0 ) continue;
}
isMatch = 1;
break;
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Changes to test/indexexpr1.test.
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} {1 1 1}
do_execsql_test indexexpr1-160eqp {
EXPLAIN QUERY PLAN
SELECT rowid, b, c FROM t1
WHERE substr(a,27,3)=='ord' AND d>=29;
} {/USING INDEX t1a2/}
do_execsql_test indexexpr1-200 {
DROP TABLE t1;
CREATE TABLE t1(id ANY PRIMARY KEY, a,b,c) WITHOUT ROWID;
INSERT INTO t1(id,a,b,c)
VALUES(1,'In_the_beginning_was_the_Word',1,1),
(2,'and_the_Word_was_with_God',1,2),
................................................................................
CREATE INDEX t72yz ON t72(y+z);
INSERT INTO t71(a,b,c) VALUES(1,11,2),(2,7,15),(3,5,4);
INSERT INTO t72(x,y,z) VALUES(1,10,3),(2,8,14),(3,9,9);
SELECT a, x, '|' FROM t71, t72
WHERE b+c=y+z
ORDER BY +a, +x;
} {1 1 | 2 2 |}
finish_test
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} {1 1 1}
do_execsql_test indexexpr1-160eqp {
EXPLAIN QUERY PLAN
SELECT rowid, b, c FROM t1
WHERE substr(a,27,3)=='ord' AND d>=29;
} {/USING INDEX t1a2/}
# ORDER BY using an indexed expression
#
do_execsql_test indexexpr1-170 {
CREATE INDEX t1alen ON t1(length(a));
SELECT length(a) FROM t1 ORDER BY length(a);
} {20 25 27 29 38 52}
do_execsql_test indexexpr1-170eqp {
EXPLAIN QUERY PLAN
SELECT length(a) FROM t1 ORDER BY length(a);
} {/SCAN TABLE t1 USING INDEX t1alen/}
do_execsql_test indexexpr1-171 {
SELECT length(a) FROM t1 ORDER BY length(a) DESC;
} {52 38 29 27 25 20}
do_execsql_test indexexpr1-171eqp {
EXPLAIN QUERY PLAN
SELECT length(a) FROM t1 ORDER BY length(a) DESC;
} {/SCAN TABLE t1 USING INDEX t1alen/}
do_execsql_test indexexpr1-200 {
DROP TABLE t1;
CREATE TABLE t1(id ANY PRIMARY KEY, a,b,c) WITHOUT ROWID;
INSERT INTO t1(id,a,b,c)
VALUES(1,'In_the_beginning_was_the_Word',1,1),
(2,'and_the_Word_was_with_God',1,2),
................................................................................
CREATE INDEX t72yz ON t72(y+z);
INSERT INTO t71(a,b,c) VALUES(1,11,2),(2,7,15),(3,5,4);
INSERT INTO t72(x,y,z) VALUES(1,10,3),(2,8,14),(3,9,9);
SELECT a, x, '|' FROM t71, t72
WHERE b+c=y+z
ORDER BY +a, +x;
} {1 1 | 2 2 |}
# Collating sequences on indexes of expressions
#
do_execsql_test indexexpr1-800 {
DROP TABLE IF EXISTS t8;
CREATE TABLE t8(a INTEGER PRIMARY KEY, b TEXT);
CREATE UNIQUE INDEX t8bx ON t8(substr(b,2,4) COLLATE nocase);
INSERT INTO t8(a,b) VALUES(1,'Alice'),(2,'Bartholemew'),(3,'Cynthia');
SELECT * FROM t8 WHERE substr(b,2,4)='ARTH' COLLATE nocase;
} {2 Bartholemew}
do_catchsql_test indexexpr1-810 {
INSERT INTO t8(a,b) VALUES(4,'BARTHMERE');
} {1 {UNIQUE constraint failed: index 't8bx'}}
do_catchsql_test indexexpr1-820 {
DROP INDEX t8bx;
CREATE UNIQUE INDEX t8bx ON t8(substr(b,2,4) COLLATE rtrim);
INSERT INTO t8(a,b) VALUES(4,'BARTHMERE');
} {0 {}}
finish_test
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