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Deactivate the DISTINCT in a SELECT on the right-hand side of an IN operator,

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since it should not make any difference in the output but dues consume extra
memory and CPU time.

FossilOrigin-Name: f4cb53651b1e352fae7378878b830a902bcd9248
This commit is contained in:
drh
2014-07-31 15:44:44 +00:00
parent 0174ffa976
commit 4387006c18
3 changed files with 15 additions and 12 deletions
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11
src/expr.c
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@@ -1624,7 +1624,7 @@ int sqlite3FindInIndex(Parse *pParse, Expr *pX, int *prNotFound){
}
if( eType==0 ){
/* Could not found an existing table or index to use as the RHS b-tree.
/* Could not find an existing table or index to use as the RHS b-tree.
** We will have to generate an ephemeral table to do the job.
*/
u32 savedNQueryLoop = pParse->nQueryLoop;
@@ -1754,6 +1754,7 @@ int sqlite3CodeSubselect(
** Generate code to write the results of the select into the temporary
** table allocated and opened above.
*/
Select *pSelect = pExpr->x.pSelect;
SelectDest dest;
ExprList *pEList;
@@ -1761,13 +1762,15 @@ int sqlite3CodeSubselect(
sqlite3SelectDestInit(&dest, SRT_Set, pExpr->iTable);
dest.affSdst = (u8)affinity;
assert( (pExpr->iTable&0x0000FFFF)==pExpr->iTable );
pExpr->x.pSelect->iLimit = 0;
pSelect->iLimit = 0;
testcase( pSelect->selFlags & SF_Distinct );
pSelect->selFlags &= ~SF_Distinct;
testcase( pKeyInfo==0 ); /* Caused by OOM in sqlite3KeyInfoAlloc() */
if( sqlite3Select(pParse, pExpr->x.pSelect, &dest) ){
if( sqlite3Select(pParse, pSelect, &dest) ){
sqlite3KeyInfoUnref(pKeyInfo);
return 0;
}
pEList = pExpr->x.pSelect->pEList;
pEList = pSelect->pEList;
assert( pKeyInfo!=0 ); /* OOM will cause exit after sqlite3Select() */
assert( pEList!=0 );
assert( pEList->nExpr>0 );