126 lines
3.1 KiB
C
126 lines
3.1 KiB
C
/*-------------------------------------------------------------------------
|
|
*
|
|
* hashutils.c--
|
|
* Utilities for finding applicable merge clauses and pathkeys
|
|
*
|
|
* Copyright (c) 1994, Regents of the University of California
|
|
*
|
|
*
|
|
* IDENTIFICATION
|
|
* $Header: /cvsroot/pgsql/src/backend/optimizer/path/Attic/hashutils.c,v 1.12 1999/02/10 03:52:39 momjian Exp $
|
|
*
|
|
*-------------------------------------------------------------------------
|
|
*/
|
|
#include "postgres.h"
|
|
#include "nodes/pg_list.h"
|
|
#include "nodes/relation.h"
|
|
|
|
#include "optimizer/internal.h"
|
|
#include "optimizer/paths.h"
|
|
#include "optimizer/clauses.h"
|
|
|
|
|
|
static HashInfo *match_hashop_hashinfo(Oid hashop, List *hashinfo_list);
|
|
|
|
/*
|
|
* group-clauses-by-hashop--
|
|
* If a join clause node in 'restrictinfo-list' is hashjoinable, store
|
|
* it within a hashinfo node containing other clause nodes with the same
|
|
* hash operator.
|
|
*
|
|
* 'restrictinfo-list' is the list of restrictinfo nodes
|
|
* 'inner-relid' is the relid of the inner join relation
|
|
*
|
|
* Returns the new list of hashinfo nodes.
|
|
*
|
|
*/
|
|
List *
|
|
group_clauses_by_hashop(List *restrictinfo_list,
|
|
int inner_relid)
|
|
{
|
|
List *hashinfo_list = NIL;
|
|
RestrictInfo *restrictinfo = (RestrictInfo *) NULL;
|
|
List *i = NIL;
|
|
Oid hashjoinop = 0;
|
|
|
|
foreach(i, restrictinfo_list)
|
|
{
|
|
restrictinfo = (RestrictInfo *) lfirst(i);
|
|
hashjoinop = restrictinfo->hashjoinoperator;
|
|
|
|
/*
|
|
* Create a new hashinfo node and add it to 'hashinfo-list' if one
|
|
* does not yet exist for this hash operator.
|
|
*/
|
|
if (hashjoinop)
|
|
{
|
|
HashInfo *xhashinfo = (HashInfo *) NULL;
|
|
Expr *clause = restrictinfo->clause;
|
|
Var *leftop = get_leftop(clause);
|
|
Var *rightop = get_rightop(clause);
|
|
JoinKey *joinkey = (JoinKey *) NULL;
|
|
|
|
xhashinfo = match_hashop_hashinfo(hashjoinop, hashinfo_list);
|
|
|
|
if (inner_relid == leftop->varno)
|
|
{
|
|
joinkey = makeNode(JoinKey);
|
|
joinkey->outer = rightop;
|
|
joinkey->inner = leftop;
|
|
}
|
|
else
|
|
{
|
|
joinkey = makeNode(JoinKey);
|
|
joinkey->outer = leftop;
|
|
joinkey->inner = rightop;
|
|
}
|
|
|
|
if (xhashinfo == NULL)
|
|
{
|
|
xhashinfo = makeNode(HashInfo);
|
|
xhashinfo->hashop = hashjoinop;
|
|
|
|
xhashinfo->jmethod.jmkeys = NIL;
|
|
xhashinfo->jmethod.clauses = NIL;
|
|
|
|
/* XXX was push */
|
|
hashinfo_list = lappend(hashinfo_list, xhashinfo);
|
|
hashinfo_list = nreverse(hashinfo_list);
|
|
}
|
|
|
|
xhashinfo->jmethod.clauses = lcons(clause, xhashinfo->jmethod.clauses);
|
|
|
|
xhashinfo->jmethod.jmkeys = lcons(joinkey, xhashinfo->jmethod.jmkeys);
|
|
}
|
|
}
|
|
return hashinfo_list;
|
|
}
|
|
|
|
|
|
/*
|
|
* match-hashop-hashinfo--
|
|
* Searches the list 'hashinfo-list' for a hashinfo node whose hash op
|
|
* field equals 'hashop'.
|
|
*
|
|
* Returns the node if it exists.
|
|
*
|
|
*/
|
|
static HashInfo *
|
|
match_hashop_hashinfo(Oid hashop, List *hashinfo_list)
|
|
{
|
|
Oid key = 0;
|
|
HashInfo *xhashinfo = (HashInfo *) NULL;
|
|
List *i = NIL;
|
|
|
|
foreach(i, hashinfo_list)
|
|
{
|
|
xhashinfo = (HashInfo *) lfirst(i);
|
|
key = xhashinfo->hashop;
|
|
if (hashop == key)
|
|
{ /* found */
|
|
return xhashinfo; /* should be a hashinfo node ! */
|
|
}
|
|
}
|
|
return (HashInfo *) NIL;
|
|
}
|