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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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10
src/backend/optimizer/util/var.c
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@ -8,7 +8,7 @@
*
*
* IDENTIFICATION
* $Header: /cvsroot/pgsql/src/backend/optimizer/util/var.c,v 1.49 2003/02/08 20:20:55 tgl Exp $
* $Header: /cvsroot/pgsql/src/backend/optimizer/util/var.c,v 1.50 2003/05/28 22:32:50 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@ -37,7 +37,7 @@ typedef struct
typedef struct
{
List *varlist;
FastList varlist;
bool includeUpperVars;
} pull_var_clause_context;
@ -344,11 +344,11 @@ pull_var_clause(Node *node, bool includeUpperVars)
{
pull_var_clause_context context;
context.varlist = NIL;
FastListInit(&context.varlist);
context.includeUpperVars = includeUpperVars;
pull_var_clause_walker(node, &context);
return context.varlist;
return FastListValue(&context.varlist);
}
static bool
@ -359,7 +359,7 @@ pull_var_clause_walker(Node *node, pull_var_clause_context *context)
if (IsA(node, Var))
{
if (((Var *) node)->varlevelsup == 0 || context->includeUpperVars)
context->varlist = lappend(context->varlist, node);
FastAppend(&context->varlist, node);
return false;
}
return expression_tree_walker(node, pull_var_clause_walker,