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Improved handling of constants and especially constant functions in the

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ORDER BY clause of a query.  Do not optimize out "ORDER BY random()".
Fix for ticket [65bdeb9739605cc2296].

FossilOrigin-Name: dca1945aeb3fb005263f9be00ee8e72b966ae303
This commit is contained in:
drh
2014-02-26 02:26:09 +00:00
parent 0baa035a1e
commit 434a93147c
4 changed files with 48 additions and 25 deletions
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21
src/where.c
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@@ -4901,9 +4901,12 @@ static int wherePathSatisfiesOrderBy(
orderDistinctMask |= pLoop->maskSelf;
for(i=0; i<nOrderBy; i++){
Expr *p;
Bitmask mTerm;
if( MASKBIT(i) & obSat ) continue;
p = pOrderBy->a[i].pExpr;
if( (exprTableUsage(&pWInfo->sMaskSet, p)&~orderDistinctMask)==0 ){
mTerm = exprTableUsage(&pWInfo->sMaskSet,p);
if( mTerm==0 && !sqlite3ExprIsConstant(p) ) continue;
if( (mTerm&~orderDistinctMask)==0 ){
obSat |= MASKBIT(i);
}
}
@@ -5526,22 +5529,6 @@ WhereInfo *sqlite3WhereBegin(
goto whereBeginError;
}
/* If the ORDER BY (or GROUP BY) clause contains references to general
** expressions, then we won't be able to satisfy it using indices, so
** go ahead and disable it now.
*/
if( pOrderBy && (wctrlFlags & WHERE_WANT_DISTINCT)!=0 ){
for(ii=0; ii<pOrderBy->nExpr; ii++){
Expr *pExpr = sqlite3ExprSkipCollate(pOrderBy->a[ii].pExpr);
if( pExpr->op!=TK_COLUMN ){
pWInfo->pOrderBy = pOrderBy = 0;
break;
}else if( pExpr->iColumn<0 ){
break;
}
}
}
if( wctrlFlags & WHERE_WANT_DISTINCT ){
if( isDistinctRedundant(pParse, pTabList, &pWInfo->sWC, pResultSet) ){
/* The DISTINCT marking is pointless. Ignore it. */