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Rewrite OR indexscan processing to be more flexible. We can now for the

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first time generate an OR indexscan for a two-column index when the WHERE
condition is like 'col1 = foo AND (col2 = bar OR col2 = baz)' --- before,
the OR had to be on the first column of the index or we'd not notice the
possibility of using it.  Some progress towards extracting OR indexscans
from subclauses of an OR that references multiple relations, too, although
this code is #ifdef'd out because it needs more work.
This commit is contained in:
Tom Lane
2004-01-04 00:07:32 +00:00
parent 037e2fcf8f
commit 6cb1c0238b
11 changed files with 452 additions and 507 deletions
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64
src/backend/optimizer/plan/initsplan.c
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@@ -8,7 +8,7 @@
*
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/optimizer/plan/initsplan.c,v 1.94 2003/12/30 23:53:14 tgl Exp $
* $PostgreSQL: pgsql/src/backend/optimizer/plan/initsplan.c,v 1.95 2004/01/04 00:07:32 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@@ -23,6 +23,7 @@
#include "optimizer/pathnode.h"
#include "optimizer/paths.h"
#include "optimizer/planmain.h"
#include "optimizer/restrictinfo.h"
#include "optimizer/tlist.h"
#include "optimizer/var.h"
#include "parser/parsetree.h"
@@ -373,31 +374,11 @@ distribute_qual_to_rels(Query *root, Node *clause,
Relids outerjoin_nonnullable,
Relids qualscope)
{
RestrictInfo *restrictinfo = makeNode(RestrictInfo);
RelOptInfo *rel;
Relids relids;
List *vars;
bool can_be_equijoin;
restrictinfo->clause = (Expr *) clause;
restrictinfo->canjoin = false; /* set below, if join clause */
restrictinfo->left_relids = NULL;
restrictinfo->right_relids = NULL;
restrictinfo->subclauseindices = NIL;
restrictinfo->eval_cost.startup = -1; /* not computed until
* needed */
restrictinfo->this_selec = -1; /* not computed until needed */
restrictinfo->mergejoinoperator = InvalidOid;
restrictinfo->left_sortop = InvalidOid;
restrictinfo->right_sortop = InvalidOid;
restrictinfo->left_pathkey = NIL; /* not computable yet */
restrictinfo->right_pathkey = NIL;
restrictinfo->left_mergescansel = -1; /* not computed until
* needed */
restrictinfo->right_mergescansel = -1;
restrictinfo->hashjoinoperator = InvalidOid;
restrictinfo->left_bucketsize = -1; /* not computed until needed */
restrictinfo->right_bucketsize = -1;
RestrictInfo *restrictinfo;
RelOptInfo *rel;
/*
* Retrieve all relids and vars contained within the clause.
@@ -508,18 +489,17 @@ distribute_qual_to_rels(Query *root, Node *clause,
* same joinrel. A qual originating from WHERE is always considered
* "pushed down".
*/
restrictinfo->ispusheddown = ispusheddown || !bms_equal(relids,
qualscope);
if (!ispusheddown)
ispusheddown = !bms_equal(relids, qualscope);
/*
* If it's a binary opclause, set up left/right relids info.
* Build the RestrictInfo node itself.
*/
if (is_opclause(clause) && length(((OpExpr *) clause)->args) == 2)
{
restrictinfo->left_relids = pull_varnos(get_leftop((Expr *) clause));
restrictinfo->right_relids = pull_varnos(get_rightop((Expr *) clause));
}
restrictinfo = make_restrictinfo((Expr *) clause, ispusheddown);
/*
* Figure out where to attach it.
*/
switch (bms_membership(relids))
{
case BMS_SINGLETON:
@@ -553,7 +533,8 @@ distribute_qual_to_rels(Query *root, Node *clause,
* into a join rel's restriction list.)
*/
if (!isdeduced ||
!qual_is_redundant(root, restrictinfo, rel->baserestrictinfo))
!qual_is_redundant(root, restrictinfo,
rel->baserestrictinfo))
{
/* Add clause to rel's restriction list */
rel->baserestrictinfo = lappend(rel->baserestrictinfo,
@@ -564,23 +545,11 @@ distribute_qual_to_rels(Query *root, Node *clause,
/*
* 'clause' is a join clause, since there is more than one rel
* in the relid set. Set additional RestrictInfo fields for
* joining. First, does it look like a normal join clause,
* i.e., a binary operator relating expressions that come from
* distinct relations? If so we might be able to use it in a
* join algorithm.
* in the relid set.
*/
if (is_opclause(clause) && length(((OpExpr *) clause)->args) == 2)
{
if (!bms_is_empty(restrictinfo->left_relids) &&
!bms_is_empty(restrictinfo->right_relids) &&
!bms_overlap(restrictinfo->left_relids,
restrictinfo->right_relids))
restrictinfo->canjoin = true;
}
/*
* Now check for hash or mergejoinable operators.
* Check for hash or mergejoinable operators.
*
* We don't bother setting the hashjoin info if we're not going
* to need it. We do want to know about mergejoinable ops in
@@ -624,7 +593,8 @@ distribute_qual_to_rels(Query *root, Node *clause,
* equivalence for future use. (We can skip this for a deduced
* clause, since the keys are already known equivalent in that case.)
*/
if (can_be_equijoin && restrictinfo->mergejoinoperator != InvalidOid &&
if (can_be_equijoin &&
restrictinfo->mergejoinoperator != InvalidOid &&
!isdeduced)
add_equijoined_keys(root, restrictinfo);
}