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Clean up handling of variable-free qual clauses. System now does the

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right thing with variable-free clauses that contain noncachable functions,
such as 'WHERE random() < 0.5' --- these are evaluated once per
potential output tuple.  Expressions that contain only Params are
now candidates to be indexscan quals --- for example, 'var = ($1 + 1)'
can now be indexed.  Cope with RelabelType nodes atop potential indexscan
variables --- this oversight prevents 7.0.* from recognizing some
potentially indexscanable situations.
This commit is contained in:
Tom Lane
2000-08-13 02:50:35 +00:00
parent 766fb7f707
commit 37168b8da4
15 changed files with 410 additions and 177 deletions
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10
src/include/optimizer/clauses.h
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@@ -7,7 +7,7 @@
* Portions Copyright (c) 1996-2000, PostgreSQL, Inc
* Portions Copyright (c) 1994, Regents of the University of California
*
* $Id: clauses.h,v 1.37 2000/05/30 04:24:57 tgl Exp $
* $Id: clauses.h,v 1.38 2000/08/13 02:50:26 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@@ -53,7 +53,13 @@ extern bool contain_subplans(Node *clause);
extern List *pull_subplans(Node *clause);
extern void check_subplans_for_ungrouped_vars(Node *clause, Query *query);
extern List *pull_constant_clauses(List *quals, List **constantQual);
extern bool contain_noncachable_functions(Node *clause);
extern bool is_pseudo_constant_clause(Node *clause);
extern List *pull_constant_clauses(List *quals,
List **noncachableQual,
List **constantQual);
extern void clause_get_relids_vars(Node *clause, Relids *relids, List **vars);
extern int NumRelids(Node *clause);