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Experimental code that tries to put the computation of subqueries inside a

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subroutine, and reuse that subroutine if the same subquery is evaluated more
than once.  Current code does not work for CHECK constraints.

FossilOrigin-Name: 6c44838adbe5dc482bc010e91a6dd7a0f777c989f443dd600740d2c783208e0d
This commit is contained in:
drh
2018-12-24 02:34:49 +00:00
parent 85bcdce270
commit 2c04131ca7
7 changed files with 121 additions and 56 deletions
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10
src/wherecode.c
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@@ -538,16 +538,17 @@ static int codeEqualityTerm(
if( pLoop->aLTerm[i]->pExpr==pX ) nEq++;
}
iTab = 0;
if( (pX->flags & EP_xIsSelect)==0 || pX->x.pSelect->pEList->nExpr==1 ){
eType = sqlite3FindInIndex(pParse, pX, IN_INDEX_LOOP, 0, 0);
eType = sqlite3FindInIndex(pParse, pX, IN_INDEX_LOOP, 0, 0, &iTab);
}else{
sqlite3 *db = pParse->db;
pX = removeUnindexableInClauseTerms(pParse, iEq, pLoop, pX);
if( !db->mallocFailed ){
aiMap = (int*)sqlite3DbMallocZero(pParse->db, sizeof(int)*nEq);
eType = sqlite3FindInIndex(pParse, pX, IN_INDEX_LOOP, 0, aiMap);
pTerm->pExpr->iTable = pX->iTable;
eType = sqlite3FindInIndex(pParse, pX, IN_INDEX_LOOP, 0, aiMap, &iTab);
pTerm->pExpr->iTable = iTab;
}
sqlite3ExprDelete(db, pX);
pX = pTerm->pExpr;
@@ -557,7 +558,6 @@ static int codeEqualityTerm(
testcase( bRev );
bRev = !bRev;
}
iTab = pX->iTable;
sqlite3VdbeAddOp2(v, bRev ? OP_Last : OP_Rewind, iTab, 0);
VdbeCoverageIf(v, bRev);
VdbeCoverageIf(v, !bRev);
@@ -2197,7 +2197,7 @@ Bitmask sqlite3WhereCodeOneLoopStart(
if( pAlt->wtFlags & (TERM_CODED) ) continue;
if( (pAlt->eOperator & WO_IN)
&& (pAlt->pExpr->flags & EP_xIsSelect)
&& (pAlt->pExpr->x.pSelect->pEList->nExpr>1)
// && (pAlt->pExpr->x.pSelect->pEList->nExpr>1)
){
continue;
}