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Marginal performance hack: use a dedicated routine instead of copyObject

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to copy nodes that are known to be Vars during plan reference adjustment.
Saves useless memzero operation as well as the big switch in copyObject.
This commit is contained in:
Tom Lane 2007-04-30 00:16:43 +00:00
parent afaa6b9821
commit 57b82bf324
1 changed files with 20 additions and 4 deletions
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24
src/backend/optimizer/plan/setrefs.c
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@ -9,7 +9,7 @@
*
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/optimizer/plan/setrefs.c,v 1.134 2007/04/06 22:57:20 tgl Exp $
* $PostgreSQL: pgsql/src/backend/optimizer/plan/setrefs.c,v 1.135 2007/04/30 00:16:43 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@ -565,6 +565,22 @@ trivial_subqueryscan(SubqueryScan *plan)
return true;
}
/*
* copyVar
* Copy a Var node.
*
* fix_scan_expr and friends do this enough times that it's worth having
* a bespoke routine instead of using the generic copyObject() function.
*/
static inline Var *
copyVar(Var *var)
{
Var *newvar = (Var *) palloc(sizeof(Var));
*newvar = *var;
return newvar;
}
/*
* fix_scan_expr
* Do set_plan_references processing on a scan-level expression
@ -588,7 +604,7 @@ fix_scan_expr_mutator(Node *node, fix_scan_expr_context *context)
return NULL;
if (IsA(node, Var))
{
Var *var = (Var *) copyObject(node);
Var *var = copyVar((Var *) node);
Assert(var->varlevelsup == 0);
/*
@ -1091,7 +1107,7 @@ search_indexed_tlist_for_var(Var *var, indexed_tlist *itlist,
if (vinfo->varno == varno && vinfo->varattno == varattno)
{
/* Found a match */
Var *newvar = (Var *) copyObject(var);
Var *newvar = copyVar(var);
newvar->varno = newvarno;
newvar->varattno = vinfo->resno;
@ -1213,7 +1229,7 @@ fix_join_expr_mutator(Node *node, fix_join_expr_context *context)
/* If it's for acceptable_rel, adjust and return it */
if (var->varno == context->acceptable_rel)
{
var = (Var *) copyObject(var);
var = copyVar(var);
var->varno += context->rtoffset;
var->varnoold += context->rtoffset;
return (Node *) var;