postgresql/src/include/optimizer/planner.h

/*-------------------------------------------------------------------------
 *
 * planner.h
 *	  prototypes for planner.c.
 *
 *
 * Portions Copyright (c) 1996-2000, PostgreSQL, Inc
 * Portions Copyright (c) 1994, Regents of the University of California
 *
 * $Id: planner.h,v 1.15 2000/03/21 05:11:51 tgl Exp $
 *
 *-------------------------------------------------------------------------
 */
#ifndef PLANNER_H
#define PLANNER_H

/*
*/

#include "nodes/parsenodes.h"
#include "nodes/plannodes.h"

extern Plan *planner(Query *parse);
extern Plan *subquery_planner(Query *parse, double tuple_fraction);
extern Plan *union_planner(Query *parse, double tuple_fraction);
extern void pg_checkretval(Oid rettype, List *querytree_list);

#endif	 /* PLANNER_H */
Postgres95 1.01 Distribution - Virgin Sources 1996-07-09 02:22:35 -04:00			`/*-------------------------------------------------------------------------`
			`*`
Change my-function-name-- to my_function_name, and optimizer renames. 1999-02-13 18:22:53 -05:00			`* planner.h`
Massive commit to run PGINDENT on all .c and .h files. 1997-09-07 01:04:48 -04:00			`* prototypes for planner.c.`
Postgres95 1.01 Distribution - Virgin Sources 1996-07-09 02:22:35 -04:00			`*`
			`*`
Add: * Portions Copyright (c) 1996-2000, PostgreSQL, Inc to all files copyright Regents of Berkeley. Man, that's a lot of files. 2000-01-26 00:58:53 -05:00			`* Portions Copyright (c) 1996-2000, PostgreSQL, Inc`
			`* Portions Copyright (c) 1994, Regents of the University of California`
Postgres95 1.01 Distribution - Virgin Sources 1996-07-09 02:22:35 -04:00			`*`
Restructure planning code so that preprocessing of targetlist and quals to simplify constant expressions and expand SubLink nodes into SubPlans is done in a separate routine subquery_planner() that calls union_planner(). We formerly did most of this work in query_planner(), but that's the wrong place because it may never see the real targetlist. Splitting union_planner into two routines also allows us to avoid redundant work when union_planner is invoked recursively for UNION and inheritance cases. Upshot is that it is now possible to do something like select float8(count()) / (select count() from int4_tbl) from int4_tbl group by f1; which has never worked before. 2000-03-21 00:12:12 -05:00			`* $Id: planner.h,v 1.15 2000/03/21 05:11:51 tgl Exp $`
Postgres95 1.01 Distribution - Virgin Sources 1996-07-09 02:22:35 -04:00			`*`
			`*-------------------------------------------------------------------------`
			`*/`
			`#ifndef PLANNER_H`
			`#define PLANNER_H`

			`/*`
			`*/`

Cleanup up include files. 1997-11-25 20:14:33 -05:00			`#include "nodes/parsenodes.h"`
			`#include "nodes/plannodes.h"`
Break parser functions into smaller files, group together. 1997-11-25 17:07:18 -05:00
Used modified version of indent that understands over 100 typedefs. 1997-09-08 17:56:23 -04:00			`extern Plan planner(Query parse);`
Restructure planning code so that preprocessing of targetlist and quals to simplify constant expressions and expand SubLink nodes into SubPlans is done in a separate routine subquery_planner() that calls union_planner(). We formerly did most of this work in query_planner(), but that's the wrong place because it may never see the real targetlist. Splitting union_planner into two routines also allows us to avoid redundant work when union_planner is invoked recursively for UNION and inheritance cases. Upshot is that it is now possible to do something like select float8(count()) / (select count() from int4_tbl) from int4_tbl group by f1; which has never worked before. 2000-03-21 00:12:12 -05:00			`extern Plan subquery_planner(Query parse, double tuple_fraction);`
New cost model for planning, incorporating a penalty for random page accesses versus sequential accesses, a (very crude) estimate of the effects of caching on random page accesses, and cost to evaluate WHERE- clause expressions. Export critical parameters for this model as SET variables. Also, create SET variables for the planner's enable flags (enable_seqscan, enable_indexscan, etc) so that these can be controlled more conveniently than via PGOPTIONS. Planner now estimates both startup cost (cost before retrieving first tuple) and total cost of each path, so it can optimize queries with LIMIT on a reasonable basis by interpolating between these costs. Same facility is a win for EXISTS(...) subqueries and some other cases. Redesign pathkey representation to achieve a major speedup in planning (I saw as much as 5X on a 10-way join); also minor changes in planner to reduce memory consumption by recycling discarded Path nodes and not constructing unnecessary lists. Minor cleanups to display more-plausible costs in some cases in EXPLAIN output. Initdb forced by change in interface to index cost estimation functions. 2000-02-15 15:49:31 -05:00			`extern Plan union_planner(Query parse, double tuple_fraction);`
Rip out QueryTreeList structure, root and branch. Querytree lists are now plain old garden-variety Lists, allocated with palloc, rather than specialized expansible-array data allocated with malloc. This substantially simplifies their handling and eliminates several sources of memory leakage. Several basic types of erroneous queries (syntax error, attempt to insert a duplicate key into a unique index) now demonstrably leak zero bytes per query. 1999-05-13 03:29:22 -04:00			`extern void pg_checkretval(Oid rettype, List *querytree_list);`
Postgres95 1.01 Distribution - Virgin Sources 1996-07-09 02:22:35 -04:00
OK, folks, here is the pgindent output. 1998-09-01 00:40:42 -04:00			`#endif /* PLANNER_H */`