postgresql/src/backend/optimizer/util/relnode.c

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/*-------------------------------------------------------------------------
*
* relnode.c--
* Relation manipulation routines
*
* Copyright (c) 1994, Regents of the University of California
*
*
* IDENTIFICATION
* $Header: /cvsroot/pgsql/src/backend/optimizer/util/relnode.c,v 1.5 1998/02/26 04:33:21 momjian Exp $
*
*-------------------------------------------------------------------------
*/
#include "postgres.h"
#include "nodes/relation.h"
#include "optimizer/internal.h"
#include "optimizer/pathnode.h" /* where the decls go */
#include "optimizer/plancat.h"
/*
* get_base_rel--
* Returns relation entry corresponding to 'relid', creating a new one if
* necessary. This is for base relations.
*
*/
Rel *
get_base_rel(Query *root, int relid)
{
List *relids;
Rel *rel;
relids = lconsi(relid, NIL);
rel = rel_member(relids, root->base_relation_list_);
if (rel == NULL)
{
rel = makeNode(Rel);
rel->relids = relids;
rel->indexed = false;
rel->pages = 0;
rel->tuples = 0;
rel->width = 0;
rel->targetlist = NIL;
rel->pathlist = NIL;
rel->unorderedpath = (Path *) NULL;
rel->cheapestpath = (Path *) NULL;
rel->pruneable = true;
rel->classlist = NULL;
rel->ordering = NULL;
rel->relam = InvalidOid;
rel->clauseinfo = NIL;
rel->joininfo = NIL;
rel->innerjoin = NIL;
rel->superrels = NIL;
root->base_relation_list_ = lcons(rel,
root->base_relation_list_);
/*
* ??? the old lispy C code (get_rel) do a listp(relid) here but
* that can never happen since we already established relid is not
* a list. -ay 10/94
*/
if (relid < 0)
{
/*
* If the relation is a materialized relation, assume
* constants for sizes.
*/
rel->pages = _TEMP_RELATION_PAGES_;
rel->tuples = _TEMP_RELATION_TUPLES_;
}
else
{
bool hasindex;
int pages,
tuples;
/*
* Otherwise, retrieve relation characteristics from the
* system catalogs.
*/
relation_info(root, relid, &hasindex, &pages, &tuples);
rel->indexed = hasindex;
rel->pages = pages;
rel->tuples = tuples;
}
}
return rel;
}
/*
* get_join_rel--
* Returns relation entry corresponding to 'relid' (a list of relids),
* creating a new one if necessary. This is for join relations.
*
*/
Rel *
get_join_rel(Query *root, List *relid)
{
return rel_member(relid, root->join_relation_list_);
}
/*
* rel-member--
* Determines whether a relation of id 'relid' is contained within a list
* 'rels'.
*
* Returns the corresponding entry in 'rels' if it is there.
*
*/
Rel *
rel_member(List *relid, List *rels)
{
List *temp = NIL;
List *temprelid = NIL;
if (relid != NIL && rels != NIL)
{
foreach(temp, rels)
{
temprelid = ((Rel *) lfirst(temp))->relids;
if (same(temprelid, relid))
return ((Rel *) (lfirst(temp)));
}
}
return (NULL);
}