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121 lines
3.0 KiB
121 lines
3.0 KiB
30 years ago
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/*-------------------------------------------------------------------------
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*
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* hashutils.c--
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* Utilities for finding applicable merge clauses and pathkeys
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*
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* Copyright (c) 1994, Regents of the University of California
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*
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*
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* IDENTIFICATION
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* $Header: /cvsroot/pgsql/src/backend/optimizer/path/Attic/hashutils.c,v 1.1.1.1 1996/07/09 06:21:35 scrappy Exp $
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*
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*-------------------------------------------------------------------------
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*/
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#include "postgres.h"
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#include "nodes/pg_list.h"
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#include "nodes/relation.h"
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#include "optimizer/internal.h"
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#include "optimizer/paths.h"
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#include "optimizer/clauses.h"
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static HInfo *match_hashop_hashinfo(Oid hashop, List *hashinfo_list);
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/*
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* group-clauses-by-hashop--
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* If a join clause node in 'clauseinfo-list' is hashjoinable, store
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* it within a hashinfo node containing other clause nodes with the same
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* hash operator.
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*
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* 'clauseinfo-list' is the list of clauseinfo nodes
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* 'inner-relid' is the relid of the inner join relation
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*
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* Returns the new list of hashinfo nodes.
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*
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*/
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List *
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group_clauses_by_hashop(List *clauseinfo_list,
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int inner_relid)
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{
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List *hashinfo_list = NIL;
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CInfo *clauseinfo = (CInfo*)NULL;
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List *i = NIL;
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Oid hashjoinop = 0;
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foreach (i,clauseinfo_list) {
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clauseinfo = (CInfo*)lfirst(i);
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hashjoinop = clauseinfo->hashjoinoperator;
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/*
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* Create a new hashinfo node and add it to 'hashinfo-list' if one
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* does not yet exist for this hash operator.
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*/
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if (hashjoinop ) {
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HInfo *xhashinfo = (HInfo*)NULL;
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Expr *clause = clauseinfo->clause;
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Var *leftop = get_leftop(clause);
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Var *rightop = get_rightop(clause);
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JoinKey *keys = (JoinKey*)NULL;
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xhashinfo =
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match_hashop_hashinfo(hashjoinop,hashinfo_list);
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if (inner_relid == leftop->varno){
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keys = makeNode(JoinKey);
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keys->outer = rightop;
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keys->inner = leftop;
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} else {
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keys = makeNode(JoinKey);
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keys->outer = leftop;
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keys->inner = rightop;
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}
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if (xhashinfo==NULL) {
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xhashinfo = makeNode(HInfo);
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xhashinfo->hashop = hashjoinop;
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xhashinfo->jmethod.jmkeys = NIL;
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xhashinfo->jmethod.clauses = NIL;
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/* XXX was push */
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hashinfo_list = lappend(hashinfo_list,xhashinfo);
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hashinfo_list = nreverse(hashinfo_list);
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}
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xhashinfo->jmethod.clauses =
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lcons(clause, xhashinfo->jmethod.clauses);
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xhashinfo->jmethod.jmkeys =
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lcons(keys, xhashinfo->jmethod.jmkeys);
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}
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}
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return(hashinfo_list);
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}
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/*
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* match-hashop-hashinfo--
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* Searches the list 'hashinfo-list' for a hashinfo node whose hash op
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* field equals 'hashop'.
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*
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* Returns the node if it exists.
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*
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*/
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static HInfo *
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match_hashop_hashinfo(Oid hashop, List *hashinfo_list)
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{
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Oid key = 0;
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HInfo *xhashinfo = (HInfo*)NULL;
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List *i = NIL;
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foreach( i, hashinfo_list) {
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xhashinfo = (HInfo*)lfirst(i);
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key = xhashinfo->hashop;
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if (hashop == key) { /* found */
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return(xhashinfo); /* should be a hashinfo node ! */
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}
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}
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return((HInfo*)NIL);
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}
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