/*-------------------------------------------------------------------------
 *
 * paths.h
 *	  prototypes for various files in optimizer/path
 *
 *
 * Portions Copyright (c) 1996-2006, PostgreSQL Global Development Group
 * Portions Copyright (c) 1994, Regents of the University of California
 *
 * $PostgreSQL: pgsql/src/include/optimizer/paths.h,v 1.92 2006/03/05 15:58:57 momjian Exp $
 *
 *-------------------------------------------------------------------------
 */
#ifndef PATHS_H
#define PATHS_H

#include "nodes/relation.h"


/*
 * allpaths.c
 */
extern bool enable_geqo;
extern int	geqo_threshold;

extern RelOptInfo *make_one_rel(PlannerInfo *root, List *joinlist);

#ifdef OPTIMIZER_DEBUG
extern void debug_print_rel(PlannerInfo *root, RelOptInfo *rel);
#endif

/*
 * indxpath.c
 *	  routines to generate index paths
 */
typedef enum
{
	/* Whether to use ScalarArrayOpExpr to build index qualifications */
	SAOP_FORBID,				/* Do not use ScalarArrayOpExpr */
	SAOP_ALLOW,					/* OK to use ScalarArrayOpExpr */
	SAOP_REQUIRE				/* Require ScalarArrayOpExpr */
} SaOpControl;

extern void create_index_paths(PlannerInfo *root, RelOptInfo *rel);
extern List *generate_bitmap_or_paths(PlannerInfo *root, RelOptInfo *rel,
						 List *clauses, List *outer_clauses,
						 bool isjoininner,
						 Relids outer_relids);
extern Path *best_inner_indexscan(PlannerInfo *root, RelOptInfo *rel,
					 Relids outer_relids, JoinType jointype);
extern List *group_clauses_by_indexkey(IndexOptInfo *index,
						  List *clauses, List *outer_clauses,
						  Relids outer_relids,
						  SaOpControl saop_control,
						  bool *found_clause);
extern bool match_index_to_operand(Node *operand, int indexcol,
					   IndexOptInfo *index);
extern List *expand_indexqual_conditions(IndexOptInfo *index,
							List *clausegroups);
extern void check_partial_indexes(PlannerInfo *root, RelOptInfo *rel);
extern List *flatten_clausegroups_list(List *clausegroups);

/*
 * orindxpath.c
 *	  additional routines for indexable OR clauses
 */
extern bool create_or_index_quals(PlannerInfo *root, RelOptInfo *rel);

/*
 * tidpath.h
 *	  routines to generate tid paths
 */
extern void create_tidscan_paths(PlannerInfo *root, RelOptInfo *rel);

/*
 * joinpath.c
 *	   routines to create join paths
 */
extern void add_paths_to_joinrel(PlannerInfo *root, RelOptInfo *joinrel,
					 RelOptInfo *outerrel,
					 RelOptInfo *innerrel,
					 JoinType jointype,
					 List *restrictlist);

/*
 * joinrels.c
 *	  routines to determine which relations to join
 */
extern List *make_rels_by_joins(PlannerInfo *root, int level, List **joinrels);
extern RelOptInfo *make_join_rel(PlannerInfo *root,
			  RelOptInfo *rel1, RelOptInfo *rel2);

/*
 * pathkeys.c
 *	  utilities for matching and building path keys
 */
typedef enum
{
	PATHKEYS_EQUAL,				/* pathkeys are identical */
	PATHKEYS_BETTER1,			/* pathkey 1 is a superset of pathkey 2 */
	PATHKEYS_BETTER2,			/* vice versa */
	PATHKEYS_DIFFERENT			/* neither pathkey includes the other */
} PathKeysComparison;

extern void add_equijoined_keys(PlannerInfo *root, RestrictInfo *restrictinfo);
extern bool exprs_known_equal(PlannerInfo *root, Node *item1, Node *item2);
extern void generate_implied_equalities(PlannerInfo *root);
extern List *canonicalize_pathkeys(PlannerInfo *root, List *pathkeys);
extern PathKeysComparison compare_pathkeys(List *keys1, List *keys2);
extern bool pathkeys_contained_in(List *keys1, List *keys2);
extern Path *get_cheapest_path_for_pathkeys(List *paths, List *pathkeys,
							   CostSelector cost_criterion);
extern Path *get_cheapest_fractional_path_for_pathkeys(List *paths,
										  List *pathkeys,
										  double fraction);
extern List *build_index_pathkeys(PlannerInfo *root, IndexOptInfo *index,
					 ScanDirection scandir, bool canonical);
extern List *convert_subquery_pathkeys(PlannerInfo *root, RelOptInfo *rel,
						  List *subquery_pathkeys);
extern List *build_join_pathkeys(PlannerInfo *root,
					RelOptInfo *joinrel,
					JoinType jointype,
					List *outer_pathkeys);
extern List *make_pathkeys_for_sortclauses(List *sortclauses,
							  List *tlist);
extern void cache_mergeclause_pathkeys(PlannerInfo *root,
						   RestrictInfo *restrictinfo);
extern List *find_mergeclauses_for_pathkeys(PlannerInfo *root,
							   List *pathkeys,
							   List *restrictinfos);
extern List *make_pathkeys_for_mergeclauses(PlannerInfo *root,
							   List *mergeclauses,
							   RelOptInfo *rel);
extern int pathkeys_useful_for_merging(PlannerInfo *root,
							RelOptInfo *rel,
							List *pathkeys);
extern int	pathkeys_useful_for_ordering(PlannerInfo *root, List *pathkeys);
extern List *truncate_useless_pathkeys(PlannerInfo *root,
						  RelOptInfo *rel,
						  List *pathkeys);

#endif   /* PATHS_H */
