128 lines
2.7 KiB
C
128 lines
2.7 KiB
C
/*-------------------------------------------------------------------------
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*
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* relnode.c
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* Relation manipulation routines
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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/util/relnode.c,v 1.18 1999/07/16 03:13:05 momjian 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 "optimizer/internal.h"
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#include "optimizer/pathnode.h"
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#include "optimizer/plancat.h"
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/*
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* get_base_rel
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* Returns relation entry corresponding to 'relid', creating a new one if
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* necessary. This is for base relations.
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*
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*/
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RelOptInfo *
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get_base_rel(Query *root, int relid)
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{
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Relids relids;
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RelOptInfo *rel;
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relids = lconsi(relid, NIL);
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rel = rel_member(relids, root->base_rel_list);
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if (rel == NULL)
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{
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rel = makeNode(RelOptInfo);
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rel->relids = relids;
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rel->indexed = false;
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rel->pages = 0;
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rel->tuples = 0;
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rel->width = 0;
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rel->targetlist = NIL;
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rel->pathlist = NIL;
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rel->cheapestpath = (Path *) NULL;
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rel->pruneable = true;
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rel->classlist = NULL;
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rel->ordering = NULL;
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rel->relam = InvalidOid;
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rel->restrictinfo = NIL;
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rel->joininfo = NIL;
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rel->innerjoin = NIL;
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root->base_rel_list = lcons(rel, root->base_rel_list);
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/*
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* ??? the old lispy C code (get_rel) do a listp(relid) here but
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* that can never happen since we already established relid is not
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* a list. -ay 10/94
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*/
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if (relid < 0)
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{
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/*
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* If the relation is a materialized relation, assume
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* constants for sizes.
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*/
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rel->pages = _NONAME_RELATION_PAGES_;
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rel->tuples = _NONAME_RELATION_TUPLES_;
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}
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else
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{
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bool hasindex;
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int pages,
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tuples;
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/*
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* Otherwise, retrieve relation characteristics from the
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* system catalogs.
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*/
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relation_info(root, relid, &hasindex, &pages, &tuples);
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rel->indexed = hasindex;
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rel->pages = pages;
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rel->tuples = tuples;
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}
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}
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return rel;
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}
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/*
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* get_join_rel
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* Returns relation entry corresponding to 'relid' (a list of relids),
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* or NULL.
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*/
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RelOptInfo *
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get_join_rel(Query *root, Relids relid)
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{
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return rel_member(relid, root->join_rel_list);
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}
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/*
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* rel_member
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* Determines whether a relation of id 'relid' is contained within a list
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* 'rels'.
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*
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* Returns the corresponding entry in 'rels' if it is there.
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*
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*/
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RelOptInfo *
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rel_member(Relids relids, List *rels)
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{
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List *temp = NIL;
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List *temprelid = NIL;
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if (relids != NIL && rels != NIL)
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{
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foreach(temp, rels)
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{
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temprelid = ((RelOptInfo *) lfirst(temp))->relids;
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if (same(temprelid, relids))
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return (RelOptInfo *) (lfirst(temp));
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}
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}
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return NULL;
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}
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