database/postgres
1
0
Fork 0
mirror of https://github.com/postgres/postgres.git synced 2025-11-22 12:22:45 +03:00
Code Activity

Fix constraint exclusion to work in inherited UPDATE/DELETE queries

Browse Source 
... in fact, it will be applied now in any query whatsoever.  I'm still
a bit concerned about the cycles that might be expended in failed proof
attempts, but given that CE is turned off by default, it's the user's
choice whether to expend those cycles or not.  (Possibly we should
change the simple bool constraint_exclusion parameter to something
more fine-grained?)
This commit is contained in:
Tom Lane
2006-02-04 23:03:20 +00:00
parent 48d9ad3722
commit 3893127431
6 changed files with 97 additions and 80 deletions
Download Patch File Download Diff File Expand all files Collapse all files

52
src/backend/optimizer/util/plancat.c
View File

@@ -9,7 +9,7 @@
*
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/optimizer/util/plancat.c,v 1.117 2006/01/31 21:39:24 tgl Exp $
* $PostgreSQL: pgsql/src/backend/optimizer/util/plancat.c,v 1.118 2006/02/04 23:03:20 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@@ -25,6 +25,7 @@
#include "nodes/makefuncs.h"
#include "optimizer/clauses.h"
#include "optimizer/plancat.h"
#include "optimizer/predtest.h"
#include "optimizer/prep.h"
#include "optimizer/tlist.h"
#include "parser/parsetree.h"
@@ -40,8 +41,13 @@
#include "miscadmin.h"
/* GUC parameter */
bool constraint_exclusion = false;
static void estimate_rel_size(Relation rel, int32 *attr_widths,
BlockNumber *pages, double *tuples);
static List *get_relation_constraints(Oid relationObjectId, RelOptInfo *rel);
/*
@@ -360,7 +366,7 @@ estimate_rel_size(Relation rel, int32 *attr_widths,
* run, and in many cases it won't be invoked at all, so there seems no
* point in caching the data in RelOptInfo.
*/
List *
static List *
get_relation_constraints(Oid relationObjectId, RelOptInfo *rel)
{
List *result = NIL;
@@ -424,6 +430,48 @@ get_relation_constraints(Oid relationObjectId, RelOptInfo *rel)
}
/*
* relation_excluded_by_constraints
*
* Detect whether the relation need not be scanned because it has CHECK
* constraints that conflict with the query's WHERE clause.
*/
bool
relation_excluded_by_constraints(RelOptInfo *rel, RangeTblEntry *rte)
{
List *constraint_pred;
/* Skip the test if constraint exclusion is disabled */
if (!constraint_exclusion)
return false;
/* Only plain relations have constraints */
if (rte->rtekind != RTE_RELATION || rte->inh)
return false;
/* OK to fetch the constraint expressions */
constraint_pred = get_relation_constraints(rte->relid, rel);
/*
* We do not currently enforce that CHECK constraints contain only
* immutable functions, so it's necessary to check here. We daren't draw
* conclusions from plan-time evaluation of non-immutable functions.
*/
if (contain_mutable_functions((Node *) constraint_pred))
return false;
/*
* The constraints are effectively ANDed together, so we can just try to
* refute the entire collection at once. This may allow us to make proofs
* that would fail if we took them individually.
*/
if (predicate_refuted_by(constraint_pred, rel->baserestrictinfo))
return true;
return false;
}
/*
* build_physical_tlist
*