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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 1.16 1999/05/25 16:10:01 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.
*
*/
RelOptInfo *
get_base_rel(Query *root, int relid)
{
Relids relids;
RelOptInfo *rel;
relids = lconsi(relid, NIL);
rel = rel_member(relids, root->base_rel_list);
if (rel == NULL)
{
rel = makeNode(RelOptInfo);
rel->relids = relids;
rel->indexed = false;
rel->pages = 0;
rel->tuples = 0;
rel->width = 0;
rel->targetlist = NIL;
rel->pathlist = NIL;
rel->cheapestpath = (Path *) NULL;
rel->pruneable = true;
rel->classlist = NULL;
rel->ordering = NULL;
rel->relam = InvalidOid;
rel->restrictinfo = NIL;
rel->joininfo = NIL;
rel->innerjoin = NIL;
root->base_rel_list = lcons(rel, root->base_rel_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 = _NONAME_RELATION_PAGES_;
rel->tuples = _NONAME_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),
* or NULL.
*/
RelOptInfo *
get_join_rel(Query *root, Relids relid)
{
return rel_member(relid, root->join_rel_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.
*
*/
RelOptInfo *
rel_member(Relids relids, List *rels)
{
List *temp = NIL;
List *temprelid = NIL;
if (relids != NIL && rels != NIL)
{
foreach(temp, rels)
{
temprelid = ((RelOptInfo *) lfirst(temp))->relids;
if (same(temprelid, relids))
return (RelOptInfo *) (lfirst(temp));
}
}
return NULL;
}
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