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postgresql/src/include/optimizer/planmain.h

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Postgres95 1.01 Distribution - Virgin Sources
1996-07-09 08:22:35 +02:00
/*-------------------------------------------------------------------------
*
Change my-function-name-- to my_function_name, and optimizer renames.
1999-02-14 00:22:53 +01:00
* planmain.h
Massive commit to run PGINDENT on all *.c and *.h files.
1997-09-07 07:04:48 +02:00
* prototypes for various files in optimizer/plan
Postgres95 1.01 Distribution - Virgin Sources
1996-07-09 08:22:35 +02:00
*
*
Update copyright to 2002.
2002-06-20 22:29:54 +02:00
* Portions Copyright (c) 1996-2002, PostgreSQL Global Development Group
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 06:58:53 +01:00
* Portions Copyright (c) 1994, Regents of the University of California
Postgres95 1.01 Distribution - Virgin Sources
1996-07-09 08:22:35 +02:00
*
Add an at-least-marginally-plausible method of estimating the number of groups produced by GROUP BY. This improves the accuracy of planning estimates for grouped subselects, and is needed to check whether a hashed aggregation plan risks memory overflow.
2002-11-20 00:22:00 +01:00
* $Id: planmain.h,v 1.62 2002/11/19 23:22:00 tgl Exp $
Postgres95 1.01 Distribution - Virgin Sources
1996-07-09 08:22:35 +02:00
*
*-------------------------------------------------------------------------
*/
#ifndef PLANMAIN_H
#define PLANMAIN_H
Cleanup up include files.
1997-11-26 02:14:33 +01:00
#include "nodes/plannodes.h"
#include "nodes/relation.h"
Postgres95 1.01 Distribution - Virgin Sources
1996-07-09 08:22:35 +02:00
/*
* prototypes for plan/planmain.c
*/
First phase of implementing hash-based grouping/aggregation. An AGG plan node now does its own grouping of the input rows, and has no need for a preceding GROUP node in the plan pipeline. This allows elimination of the misnamed tuplePerGroup option for GROUP, and actually saves more code in nodeGroup.c than it costs in nodeAgg.c, as well as being presumably faster. Restructure the API of query_planner so that we do not commit to using a sorted or unsorted plan in query_planner; instead grouping_planner makes the decision. (Right now it isn't any smarter than query_planner was, but that will change as soon as it has the option to select a hash- based aggregation step.) Despite all the hackery, no initdb needed since only in-memory node types changed.
2002-11-06 01:00:45 +01:00
extern void query_planner(Query *root, List *tlist, double tuple_fraction,
Path **cheapest_path, Path **sorted_path);
Postgres95 1.01 Distribution - Virgin Sources
1996-07-09 08:22:35 +02:00
/*
* prototypes for plan/createplan.c
*/
Another round of planner/optimizer work. This is just restructuring and code cleanup; no major improvements yet. However, EXPLAIN does produce more intuitive outputs for nested loops with indexscans now...
2000-01-09 01:26:47 +01:00
extern Plan *create_plan(Query *root, Path *best_path);
Reimplementation of UNION/INTERSECT/EXCEPT. INTERSECT/EXCEPT now meet the SQL92 semantics, including support for ALL option. All three can be used in subqueries and views. DISTINCT and ORDER BY work now in views, too. This rewrite fixes many problems with cross-datatype UNIONs and INSERT/SELECT where the SELECT yields different datatypes than the INSERT needs. I did that by making UNION subqueries and SELECT in INSERT be treated like subselects-in-FROM, thereby allowing an extra level of targetlist where the datatype conversions can be inserted safely. INITDB NEEDED!
2000-10-05 21:11:39 +02:00
extern SubqueryScan *make_subqueryscan(List *qptlist, List *qpqual,
pgindent run. Make it all clean.
2001-03-22 05:01:46 +01:00
Index scanrelid, Plan *subplan);
Restructure handling of inheritance queries so that they work with outer joins, and clean things up a good deal at the same time. Append plan node no longer hacks on rangetable at runtime --- instead, all child tables are given their own RT entries during planning. Concept of multiple target tables pushed up into execMain, replacing bug-prone implementation within nodeAppend. Planner now supports generating Append plans for inheritance sets either at the top of the plan (the old way) or at the bottom. Expanding at the bottom is appropriate for tables used as sources, since they may appear inside an outer join; but we must still expand at the top when the target of an UPDATE or DELETE is an inheritance set, because we actually need a different targetlist and junkfilter for each target table in that case. Fortunately a target table can't be inside an outer join... Bizarre mutual recursion between union_planner and prepunion.c is gone --- in fact, union_planner doesn't really have much to do with union queries anymore, so I renamed it grouping_planner.
2000-11-12 01:37:02 +01:00
extern Append *make_append(List *appendplans, bool isTarget, List *tlist);
Further work on making use of new statistics in planner. Adjust APIs of costsize.c routines to pass Query root, so that costsize can figure more things out by itself and not be so dependent on its callers to tell it everything it needs to know. Use selectivity of hash or merge clause to estimate number of tuples processed internally in these joins (this is more useful than it would've been before, since eqjoinsel is somewhat more accurate than before).
2001-06-05 07:26:05 +02:00
extern Sort *make_sort(Query *root, List *tlist,
pgindent run on all C files. Java run to follow. initdb/regression tests pass.
2001-10-25 07:50:21 +02:00
Plan *lefttree, int keycount);
Further work on making use of new statistics in planner. Adjust APIs of costsize.c routines to pass Query root, so that costsize can figure more things out by itself and not be so dependent on its callers to tell it everything it needs to know. Use selectivity of hash or merge clause to estimate number of tuples processed internally in these joins (this is more useful than it would've been before, since eqjoinsel is somewhat more accurate than before).
2001-06-05 07:26:05 +02:00
extern Sort *make_sort_from_pathkeys(Query *root, List *tlist,
pgindent run on all C files. Java run to follow. initdb/regression tests pass.
2001-10-25 07:50:21 +02:00
Plan *lefttree, List *pathkeys);
First phase of implementing hash-based grouping/aggregation. An AGG plan node now does its own grouping of the input rows, and has no need for a preceding GROUP node in the plan pipeline. This allows elimination of the misnamed tuplePerGroup option for GROUP, and actually saves more code in nodeGroup.c than it costs in nodeAgg.c, as well as being presumably faster. Restructure the API of query_planner so that we do not commit to using a sorted or unsorted plan in query_planner; instead grouping_planner makes the decision. (Right now it isn't any smarter than query_planner was, but that will change as soon as it has the option to select a hash- based aggregation step.) Despite all the hackery, no initdb needed since only in-memory node types changed.
2002-11-06 01:00:45 +01:00
extern Agg *make_agg(List *tlist, List *qual, AggStrategy aggstrategy,
Add an at-least-marginally-plausible method of estimating the number of groups produced by GROUP BY. This improves the accuracy of planning estimates for grouped subselects, and is needed to check whether a hashed aggregation plan risks memory overflow.
2002-11-20 00:22:00 +01:00
int ngrp, AttrNumber *grpColIdx,
long numGroups, int numAggs,
Plan *lefttree);
extern Group *make_group(List *tlist,
int ngrp, AttrNumber *grpColIdx, double numGroups,
First phase of implementing hash-based grouping/aggregation. An AGG plan node now does its own grouping of the input rows, and has no need for a preceding GROUP node in the plan pipeline. This allows elimination of the misnamed tuplePerGroup option for GROUP, and actually saves more code in nodeGroup.c than it costs in nodeAgg.c, as well as being presumably faster. Restructure the API of query_planner so that we do not commit to using a sorted or unsorted plan in query_planner; instead grouping_planner makes the decision. (Right now it isn't any smarter than query_planner was, but that will change as soon as it has the option to select a hash- based aggregation step.) Despite all the hackery, no initdb needed since only in-memory node types changed.
2002-11-06 01:00:45 +01:00
Plan *lefttree);
Reimplement nodeMaterial to use a temporary BufFile (or even memory, if the materialized tupleset is small enough) instead of a temporary relation. This was something I was thinking of doing anyway for performance, and Jan says he needs it for TOAST because he doesn't want to cope with toasting noname relations. With this change, the 'noname table' support in heap.c is dead code, and I have accordingly removed it. Also clean up 'noname' plan handling in planner --- nonames are either sort or materialize plans, and it seems less confusing to handle them separately under those names.
2000-06-19 00:44:35 +02:00
extern Material *make_material(List *tlist, Plan *lefttree);
Redesign DISTINCT ON as discussed in pgsql-sql 1/25/00: syntax is now SELECT DISTINCT ON (expr [, expr ...]) targetlist ... and there is a check to make sure that the user didn't specify an ORDER BY that's incompatible with the DISTINCT operation. Reimplement nodeUnique and nodeGroup to use the proper datatype-specific equality function for each column being compared --- they used to do bitwise comparisons or convert the data to text strings and strcmp(). (To add insult to injury, they'd look up the conversion functions once for each tuple...) Parse/plan representation of DISTINCT is now a list of SortClause nodes. initdb forced by querytree change...
2000-01-27 19:11:50 +01:00
extern Unique *make_unique(List *tlist, Plan *lefttree, List *distinctList);
Re-implement LIMIT/OFFSET as a plan node type, instead of a hack in ExecutorRun. This allows LIMIT to work in a view. Also, LIMIT in a cursor declaration will behave in a reasonable fashion, whereas before it was overridden by the FETCH count.
2000-10-26 23:38:24 +02:00
extern Limit *make_limit(List *tlist, Plan *lefttree,
pgindent run. Make it all clean.
2001-03-22 05:01:46 +01:00
Node *limitOffset, Node *limitCount);
Reimplementation of UNION/INTERSECT/EXCEPT. INTERSECT/EXCEPT now meet the SQL92 semantics, including support for ALL option. All three can be used in subqueries and views. DISTINCT and ORDER BY work now in views, too. This rewrite fixes many problems with cross-datatype UNIONs and INSERT/SELECT where the SELECT yields different datatypes than the INSERT needs. I did that by making UNION subqueries and SELECT in INSERT be treated like subselects-in-FROM, thereby allowing an extra level of targetlist where the datatype conversions can be inserted safely. INITDB NEEDED!
2000-10-05 21:11:39 +02:00
extern SetOp *make_setop(SetOpCmd cmd, List *tlist, Plan *lefttree,
pgindent run. Make it all clean.
2001-03-22 05:01:46 +01:00
List *distinctList, AttrNumber flagColIdx);
Further planner/optimizer cleanups. Move all set_tlist_references and fix_opids processing to a single recursive pass over the plan tree executed at the very tail end of planning, rather than haphazardly here and there at different places. Now that tlist Vars do not get modified until the very end, it's possible to get rid of the klugy var_equal and match_varid partial-matching routines, and just use plain equal() throughout the optimizer. This is a step towards allowing merge and hash joins to be done on expressions instead of only Vars ...
1999-08-22 22:15:04 +02:00
extern Result *make_result(List *tlist, Node *resconstantqual, Plan *subplan);
Postgres95 1.01 Distribution - Virgin Sources
1996-07-09 08:22:35 +02:00
/*
* prototypes for plan/initsplan.c
*/
Restructure representation of join alias variables. An explicit JOIN now has an RTE of its own, and references to its outputs now are Vars referencing the JOIN RTE, rather than CASE-expressions. This allows reverse-listing in ruleutils.c to use the correct alias easily, rather than painfully reverse-engineering the alias namespace as it used to do. Also, nested FULL JOINs work correctly, because the result of the inner joins are simple Vars that the planner can cope with. This fixes a bug reported a couple times now, notably by Tatsuo on 18-Nov-01. The alias Vars are expanded into COALESCE expressions where needed at the very end of planning, rather than during parsing. Also, beginnings of support for showing plan qualifier expressions in EXPLAIN. There are probably still cases that need work. initdb forced due to change of stored-rule representation.
2002-03-12 01:52:10 +01:00
extern List *add_base_rels_to_query(Query *root, Node *jtnode);
First cut at full support for OUTER JOINs. There are still a few loose ends to clean up (see my message of same date to pghackers), but mostly it works. INITDB REQUIRED!
2000-09-12 23:07:18 +02:00
extern void build_base_rel_tlists(Query *root, List *tlist);
Subselects in FROM clause, per ISO syntax: FROM (SELECT ...) [AS] alias. (Don't forget that an alias is required.) Views reimplemented as expanding to subselect-in-FROM. Grouping, aggregates, DISTINCT in views actually work now (he says optimistically). No UNION support in subselects/views yet, but I have some ideas about that. Rule-related permissions checking moved out of rewriter and into executor. INITDB REQUIRED!
2000-09-29 20:21:41 +02:00
extern Relids distribute_quals_to_rels(Query *root, Node *jtnode);
Deduce equality constraints that are implied by transitivity of mergejoinable qual clauses, and add them to the query quals. For example, WHERE a = b AND b = c will cause us to add AND a = c. This is necessary to ensure that it's safe to use these variables as interchangeable sort keys, which is something 7.0 knows how to do. Should provide a useful improvement in planning ability, too.
2000-07-24 05:11:01 +02:00
extern void process_implied_equality(Query *root, Node *item1, Node *item2,
pgindent run. Make it all clean.
2001-03-22 05:01:46 +01:00
Oid sortop1, Oid sortop2);
Add an at-least-marginally-plausible method of estimating the number of groups produced by GROUP BY. This improves the accuracy of planning estimates for grouped subselects, and is needed to check whether a hashed aggregation plan risks memory overflow.
2002-11-20 00:22:00 +01:00
extern bool vars_known_equal(Query *root, Var *var1, Var *var2);
Postgres95 1.01 Distribution - Virgin Sources
1996-07-09 08:22:35 +02:00
/*
* prototypes for plan/setrefs.c
*/
Change set_plan_references and join_references to take an rtable List rather than a Query node; this allows set_plan_references to recurse into subplans correctly. Fixes core dump on full outer joins in subplans. Also, invoke preprocess_expression on function RTEs' function expressions. This seems to fix the planner's problems with outer-level Vars in function RTEs.
2002-05-18 04:25:50 +02:00
extern void set_plan_references(Plan *plan, List *rtable);
extern List *join_references(List *clauses, List *rtable,
pgindent run.
2002-09-04 22:31:48 +02:00
List *outer_tlist, List *inner_tlist,
Index acceptable_rel);
Further planner/optimizer cleanups. Move all set_tlist_references and fix_opids processing to a single recursive pass over the plan tree executed at the very tail end of planning, rather than haphazardly here and there at different places. Now that tlist Vars do not get modified until the very end, it's possible to get rid of the klugy var_equal and match_varid partial-matching routines, and just use plain equal() throughout the optimizer. This is a step towards allowing merge and hash joins to be done on expressions instead of only Vars ...
1999-08-22 22:15:04 +02:00
extern void fix_opids(Node *node);
Major revision of sort-node handling: push knowledge of query sort order down into planner, instead of handling it only at the very top level of the planner. This fixes many things. An explicit sort is now avoided if there is a cheaper alternative (typically an indexscan) not only for ORDER BY, but also for the internal sort of GROUP BY. It works even when there is no other reason (such as a WHERE condition) to consider the indexscan. It works for indexes on functions. It works for indexes on functions, backwards. It's just so cool... CAUTION: I have changed the representation of SortClause nodes, therefore THIS UPDATE BREAKS STORED RULES. You will need to initdb.
1999-08-21 05:49:17 +02:00
New pgindent run with fixes suggested by Tom. Patch manually reviewed, initdb/regression tests pass.
2001-11-05 18:46:40 +01:00
#endif /* PLANMAIN_H */