Fix set_append_rel_pathlist() to deal intelligently with cases where
substituting a child rel's output expressions into the appendrel's restriction clauses yields a pseudoconstant restriction. We might be able to skip scanning that child rel entirely (if we get constant FALSE), or generate a one-time filter. 8.3 more or less accidentally generated plans that weren't completely stupid in these cases, but that was only because an extra recursive level of subquery_planner() always occurred and allowed const-simplification to happen. 8.4's ability to pull up appendrel members with non-Var outputs exposes the fact that we need to work harder here. Per gripe from Sergey Burladyan.
This commit is contained in:
Tom Lane
parent
bf6570abef
commit
9b27eab71c
|
|
@ -8,7 +8,7 @@
|
|||
*
|
||||
*
|
||||
* IDENTIFICATION
|
||||
* $PostgreSQL: pgsql/src/backend/optimizer/path/allpaths.c,v 1.183 2009/06/11 14:48:58 momjian Exp $
|
||||
* $PostgreSQL: pgsql/src/backend/optimizer/path/allpaths.c,v 1.184 2009/07/06 18:26:30 tgl Exp $
|
||||
*
|
||||
*-------------------------------------------------------------------------
|
||||
*/
|
||||
|
|
@ -29,6 +29,7 @@
|
|||
#include "optimizer/plancat.h"
|
||||
#include "optimizer/planner.h"
|
||||
#include "optimizer/prep.h"
|
||||
#include "optimizer/restrictinfo.h"
|
||||
#include "optimizer/var.h"
|
||||
#include "parser/parse_clause.h"
|
||||
#include "parser/parsetree.h"
|
||||
|
|
@ -318,6 +319,8 @@ set_append_rel_pathlist(PlannerInfo *root, RelOptInfo *rel,
|
|||
int childRTindex;
|
||||
RangeTblEntry *childRTE;
|
||||
RelOptInfo *childrel;
|
||||
List *childquals;
|
||||
Node *childqual;
|
||||
Path *childpath;
|
||||
ListCell *parentvars;
|
||||
ListCell *childvars;
|
||||
|
|
@ -342,10 +345,34 @@ set_append_rel_pathlist(PlannerInfo *root, RelOptInfo *rel,
|
|||
* baserestrictinfo quals are needed before we can check for
|
||||
* constraint exclusion; so do that first and then check to see if we
|
||||
* can disregard this child.
|
||||
*
|
||||
* As of 8.4, the child rel's targetlist might contain non-Var
|
||||
* expressions, which means that substitution into the quals
|
||||
* could produce opportunities for const-simplification, and perhaps
|
||||
* even pseudoconstant quals. To deal with this, we strip the
|
||||
* RestrictInfo nodes, do the substitution, do const-simplification,
|
||||
* and then reconstitute the RestrictInfo layer.
|
||||
*/
|
||||
childrel->baserestrictinfo = (List *)
|
||||
adjust_appendrel_attrs((Node *) rel->baserestrictinfo,
|
||||
appinfo);
|
||||
childquals = get_all_actual_clauses(rel->baserestrictinfo);
|
||||
childquals = (List *) adjust_appendrel_attrs((Node *) childquals,
|
||||
appinfo);
|
||||
childqual = eval_const_expressions(root, (Node *)
|
||||
make_ands_explicit(childquals));
|
||||
if (childqual && IsA(childqual, Const) &&
|
||||
(((Const *) childqual)->constisnull ||
|
||||
!DatumGetBool(((Const *) childqual)->constvalue)))
|
||||
{
|
||||
/*
|
||||
* Restriction reduces to constant FALSE or constant NULL after
|
||||
* substitution, so this child need not be scanned.
|
||||
*/
|
||||
set_dummy_rel_pathlist(childrel);
|
||||
continue;
|
||||
}
|
||||
childquals = make_ands_implicit((Expr *) childqual);
|
||||
childquals = make_restrictinfos_from_actual_clauses(root,
|
||||
childquals);
|
||||
childrel->baserestrictinfo = childquals;
|
||||
|
||||
if (relation_excluded_by_constraints(root, childrel, childRTE))
|
||||
{
|
||||
|
|
|
|||
|
|
@ -22,7 +22,7 @@
|
|||
*
|
||||
*
|
||||
* IDENTIFICATION
|
||||
* $PostgreSQL: pgsql/src/backend/optimizer/prep/prepunion.c,v 1.171 2009/06/11 14:48:59 momjian Exp $
|
||||
* $PostgreSQL: pgsql/src/backend/optimizer/prep/prepunion.c,v 1.172 2009/07/06 18:26:30 tgl Exp $
|
||||
*
|
||||
*-------------------------------------------------------------------------
|
||||
*/
|
||||
|
|
@ -1636,57 +1636,7 @@ adjust_appendrel_attrs_mutator(Node *node, AppendRelInfo *context)
|
|||
Assert(!IsA(node, SpecialJoinInfo));
|
||||
Assert(!IsA(node, AppendRelInfo));
|
||||
Assert(!IsA(node, PlaceHolderInfo));
|
||||
|
||||
/*
|
||||
* We have to process RestrictInfo nodes specially.
|
||||
*/
|
||||
if (IsA(node, RestrictInfo))
|
||||
{
|
||||
RestrictInfo *oldinfo = (RestrictInfo *) node;
|
||||
RestrictInfo *newinfo = makeNode(RestrictInfo);
|
||||
|
||||
/* Copy all flat-copiable fields */
|
||||
memcpy(newinfo, oldinfo, sizeof(RestrictInfo));
|
||||
|
||||
/* Recursively fix the clause itself */
|
||||
newinfo->clause = (Expr *)
|
||||
adjust_appendrel_attrs_mutator((Node *) oldinfo->clause, context);
|
||||
|
||||
/* and the modified version, if an OR clause */
|
||||
newinfo->orclause = (Expr *)
|
||||
adjust_appendrel_attrs_mutator((Node *) oldinfo->orclause, context);
|
||||
|
||||
/* adjust relid sets too */
|
||||
newinfo->clause_relids = adjust_relid_set(oldinfo->clause_relids,
|
||||
context->parent_relid,
|
||||
context->child_relid);
|
||||
newinfo->required_relids = adjust_relid_set(oldinfo->required_relids,
|
||||
context->parent_relid,
|
||||
context->child_relid);
|
||||
newinfo->left_relids = adjust_relid_set(oldinfo->left_relids,
|
||||
context->parent_relid,
|
||||
context->child_relid);
|
||||
newinfo->right_relids = adjust_relid_set(oldinfo->right_relids,
|
||||
context->parent_relid,
|
||||
context->child_relid);
|
||||
|
||||
/*
|
||||
* Reset cached derivative fields, since these might need to have
|
||||
* different values when considering the child relation.
|
||||
*/
|
||||
newinfo->eval_cost.startup = -1;
|
||||
newinfo->norm_selec = -1;
|
||||
newinfo->outer_selec = -1;
|
||||
newinfo->left_ec = NULL;
|
||||
newinfo->right_ec = NULL;
|
||||
newinfo->left_em = NULL;
|
||||
newinfo->right_em = NULL;
|
||||
newinfo->scansel_cache = NIL;
|
||||
newinfo->left_bucketsize = -1;
|
||||
newinfo->right_bucketsize = -1;
|
||||
|
||||
return (Node *) newinfo;
|
||||
}
|
||||
Assert(!IsA(node, RestrictInfo));
|
||||
|
||||
/*
|
||||
* NOTE: we do not need to recurse into sublinks, because they should
|
||||
|
|
|
|||
|
|
@ -8,7 +8,7 @@
|
|||
*
|
||||
*
|
||||
* IDENTIFICATION
|
||||
* $PostgreSQL: pgsql/src/backend/optimizer/util/restrictinfo.c,v 1.60 2009/06/11 14:48:59 momjian Exp $
|
||||
* $PostgreSQL: pgsql/src/backend/optimizer/util/restrictinfo.c,v 1.61 2009/07/06 18:26:30 tgl Exp $
|
||||
*
|
||||
*-------------------------------------------------------------------------
|
||||
*/
|
||||
|
|
@ -271,6 +271,57 @@ make_restrictinfo_from_bitmapqual(Path *bitmapqual,
|
|||
return result;
|
||||
}
|
||||
|
||||
/*
|
||||
* make_restrictinfos_from_actual_clauses
|
||||
*
|
||||
* Given a list of implicitly-ANDed restriction clauses, produce a list
|
||||
* of RestrictInfo nodes. This is used to reconstitute the RestrictInfo
|
||||
* representation after doing transformations of a list of clauses.
|
||||
*
|
||||
* We assume that the clauses are relation-level restrictions and therefore
|
||||
* we don't have to worry about is_pushed_down, outerjoin_delayed, or
|
||||
* nullable_relids (these can be assumed true, false, and NULL, respectively).
|
||||
* We do take care to recognize pseudoconstant clauses properly.
|
||||
*/
|
||||
List *
|
||||
make_restrictinfos_from_actual_clauses(PlannerInfo *root,
|
||||
List *clause_list)
|
||||
{
|
||||
List *result = NIL;
|
||||
ListCell *l;
|
||||
|
||||
foreach(l, clause_list)
|
||||
{
|
||||
Expr *clause = (Expr *) lfirst(l);
|
||||
bool pseudoconstant;
|
||||
RestrictInfo *rinfo;
|
||||
|
||||
/*
|
||||
* It's pseudoconstant if it contains no Vars and no volatile
|
||||
* functions. We probably can't see any sublinks here, so
|
||||
* contain_var_clause() would likely be enough, but for safety
|
||||
* use contain_vars_of_level() instead.
|
||||
*/
|
||||
pseudoconstant =
|
||||
!contain_vars_of_level((Node *) clause, 0) &&
|
||||
!contain_volatile_functions((Node *) clause);
|
||||
if (pseudoconstant)
|
||||
{
|
||||
/* tell createplan.c to check for gating quals */
|
||||
root->hasPseudoConstantQuals = true;
|
||||
}
|
||||
|
||||
rinfo = make_restrictinfo(clause,
|
||||
true,
|
||||
false,
|
||||
pseudoconstant,
|
||||
NULL,
|
||||
NULL);
|
||||
result = lappend(result, rinfo);
|
||||
}
|
||||
return result;
|
||||
}
|
||||
|
||||
/*
|
||||
* make_restrictinfo_internal
|
||||
*
|
||||
|
|
@ -481,6 +532,31 @@ get_actual_clauses(List *restrictinfo_list)
|
|||
return result;
|
||||
}
|
||||
|
||||
/*
|
||||
* get_all_actual_clauses
|
||||
*
|
||||
* Returns a list containing the bare clauses from 'restrictinfo_list'.
|
||||
*
|
||||
* This loses the distinction between regular and pseudoconstant clauses,
|
||||
* so be careful what you use it for.
|
||||
*/
|
||||
List *
|
||||
get_all_actual_clauses(List *restrictinfo_list)
|
||||
{
|
||||
List *result = NIL;
|
||||
ListCell *l;
|
||||
|
||||
foreach(l, restrictinfo_list)
|
||||
{
|
||||
RestrictInfo *rinfo = (RestrictInfo *) lfirst(l);
|
||||
|
||||
Assert(IsA(rinfo, RestrictInfo));
|
||||
|
||||
result = lappend(result, rinfo->clause);
|
||||
}
|
||||
return result;
|
||||
}
|
||||
|
||||
/*
|
||||
* extract_actual_clauses
|
||||
*
|
||||
|
|
|
|||
|
|
@ -7,7 +7,7 @@
|
|||
* Portions Copyright (c) 1996-2009, PostgreSQL Global Development Group
|
||||
* Portions Copyright (c) 1994, Regents of the University of California
|
||||
*
|
||||
* $PostgreSQL: pgsql/src/include/optimizer/restrictinfo.h,v 1.44 2009/05/09 22:51:41 tgl Exp $
|
||||
* $PostgreSQL: pgsql/src/include/optimizer/restrictinfo.h,v 1.45 2009/07/06 18:26:30 tgl Exp $
|
||||
*
|
||||
*-------------------------------------------------------------------------
|
||||
*/
|
||||
|
|
@ -30,8 +30,11 @@ extern RestrictInfo *make_restrictinfo(Expr *clause,
|
|||
extern List *make_restrictinfo_from_bitmapqual(Path *bitmapqual,
|
||||
bool is_pushed_down,
|
||||
bool include_predicates);
|
||||
extern List *make_restrictinfos_from_actual_clauses(PlannerInfo *root,
|
||||
List *clause_list);
|
||||
extern bool restriction_is_or_clause(RestrictInfo *restrictinfo);
|
||||
extern List *get_actual_clauses(List *restrictinfo_list);
|
||||
extern List *get_all_actual_clauses(List *restrictinfo_list);
|
||||
extern List *extract_actual_clauses(List *restrictinfo_list,
|
||||
bool pseudoconstant);
|
||||
extern void extract_actual_join_clauses(List *restrictinfo_list,
|
||||
|
|
|
|||
Loading…
Reference in a new issue