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Fix some planner performance problems with large WHERE clauses, by

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introducing new 'FastList' list-construction subroutines to use in
hot spots.  This avoids the O(N^2) behavior of repeated lappend's
by keeping a tail pointer, while not changing behavior by reversing
list order as the lcons() method would do.
This commit is contained in:
Tom Lane
2003-05-28 22:32:50 +00:00
parent 0f3c68aa43
commit 8a6ac83dab
8 changed files with 374 additions and 202 deletions
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34
src/backend/executor/execQual.c
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@ -8,7 +8,7 @@
*
*
* IDENTIFICATION
* $Header: /cvsroot/pgsql/src/backend/executor/execQual.c,v 1.129 2003/05/02 20:54:33 tgl Exp $
* $Header: /cvsroot/pgsql/src/backend/executor/execQual.c,v 1.130 2003/05/28 22:32:49 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@ -2320,9 +2320,10 @@ ExecInitExpr(Expr *node, PlanState *parent)
{
CaseExpr *caseexpr = (CaseExpr *) node;
CaseExprState *cstate = makeNode(CaseExprState);
List *outlist = NIL;
FastList outlist;
List *inlist;
FastListInit(&outlist);
foreach(inlist, caseexpr->args)
{
CaseWhen *when = (CaseWhen *) lfirst(inlist);
@ -2332,9 +2333,9 @@ ExecInitExpr(Expr *node, PlanState *parent)
wstate->xprstate.expr = (Expr *) when;
wstate->expr = ExecInitExpr(when->expr, parent);
wstate->result = ExecInitExpr(when->result, parent);
outlist = lappend(outlist, wstate);
FastAppend(&outlist, wstate);
}
cstate->args = outlist;
cstate->args = FastListValue(&outlist);
/* caseexpr->arg should be null by now */
Assert(caseexpr->arg == NULL);
cstate->defresult = ExecInitExpr(caseexpr->defresult, parent);
@ -2345,18 +2346,19 @@ ExecInitExpr(Expr *node, PlanState *parent)
{
ArrayExpr *arrayexpr = (ArrayExpr *) node;
ArrayExprState *astate = makeNode(ArrayExprState);
List *outlist = NIL;
FastList outlist;
List *inlist;
FastListInit(&outlist);
foreach(inlist, arrayexpr->elements)
{
Expr *e = (Expr *) lfirst(inlist);
ExprState *estate;
estate = ExecInitExpr(e, parent);
outlist = lappend(outlist, estate);
FastAppend(&outlist, estate);
}
astate->elements = outlist;
astate->elements = FastListValue(&outlist);
/* do one-time catalog lookup for type info */
get_typlenbyvalalign(arrayexpr->element_typeid,
&astate->elemlength,
@ -2369,18 +2371,19 @@ ExecInitExpr(Expr *node, PlanState *parent)
{
CoalesceExpr *coalesceexpr = (CoalesceExpr *) node;
CoalesceExprState *cstate = makeNode(CoalesceExprState);
List *outlist = NIL;
FastList outlist;
List *inlist;
FastListInit(&outlist);
foreach(inlist, coalesceexpr->args)
{
Expr *e = (Expr *) lfirst(inlist);
ExprState *estate;
estate = ExecInitExpr(e, parent);
outlist = lappend(outlist, estate);
FastAppend(&outlist, estate);
}
cstate->args = outlist;
cstate->args = FastListValue(&outlist);
state = (ExprState *) cstate;
}
break;
@ -2434,17 +2437,18 @@ ExecInitExpr(Expr *node, PlanState *parent)
break;
case T_List:
{
List *outlist = NIL;
FastList outlist;
List *inlist;
FastListInit(&outlist);
foreach(inlist, (List *) node)
{
outlist = lappend(outlist,
ExecInitExpr((Expr *) lfirst(inlist),
parent));
FastAppend(&outlist,
ExecInitExpr((Expr *) lfirst(inlist),
parent));
}
/* Don't fall through to the "common" code below */
return (ExprState *) outlist;
return (ExprState *) FastListValue(&outlist);
}
default:
elog(ERROR, "ExecInitExpr: unknown expression type %d",