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postgresql/src/include/optimizer/subselect.h

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Subselects...
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/*-------------------------------------------------------------------------
*
Change my-function-name-- to my_function_name, and optimizer renames.
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* subselect.h
Subselects...
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*
Update copyright for the year 2010.
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* Portions Copyright (c) 1996-2010, PostgreSQL Global Development Group
IN clauses appearing at top level of WHERE can now be handled as joins. There are two implementation techniques: the executor understands a new JOIN_IN jointype, which emits at most one matching row per left-hand row, or the result of the IN's sub-select can be fed through a DISTINCT filter and then joined as an ordinary relation. Along the way, some minor code cleanup in the optimizer; notably, break out most of the jointree-rearrangement preprocessing in planner.c and put it in a new file prep/prepjointree.c.
2003-01-20 13:55:07 -05:00
* Portions Copyright (c) 1994, Regents of the University of California
*
Remove cvs keywords from all files.
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* src/include/optimizer/subselect.h
IN clauses appearing at top level of WHERE can now be handled as joins. There are two implementation techniques: the executor understands a new JOIN_IN jointype, which emits at most one matching row per left-hand row, or the result of the IN's sub-select can be fed through a DISTINCT filter and then joined as an ordinary relation. Along the way, some minor code cleanup in the optimizer; notably, break out most of the jointree-rearrangement preprocessing in planner.c and put it in a new file prep/prepjointree.c.
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*
Subselects...
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*-------------------------------------------------------------------------
*/
#ifndef SUBSELECT_H
#define SUBSELECT_H
Cleanup of /include #include's, for 6.6 only.
1999-07-13 21:20:30 -04:00
#include "nodes/plannodes.h"
Remove planner's private fields from Query struct, and put them into a new PlannerInfo struct, which is passed around instead of the bare Query in all the planning code. This commit is essentially just a code-beautification exercise, but it does open the door to making larger changes to the planner data structures without having to muck with the widely-known Query struct.
2005-06-05 18:32:58 -04:00
#include "nodes/relation.h"
Implement SQL-standard WITH clauses, including WITH RECURSIVE. There are some unimplemented aspects: recursive queries must use UNION ALL (should allow UNION too), and we don't have SEARCH or CYCLE clauses. These might or might not get done for 8.4, but even without them it's a pretty useful feature. There are also a couple of small loose ends and definitional quibbles, which I'll send a memo about to pgsql-hackers shortly. But let's land the patch now so we can get on with other development. Yoshiyuki Asaba, with lots of help from Tatsuo Ishii and Tom Lane
2008-10-04 17:56:55 -04:00
extern void SS_process_ctes(PlannerInfo *root);
Get rid of the rather fuzzily defined FlattenedSubLink node type in favor of making pull_up_sublinks() construct a full-blown JoinExpr tree representation of IN/EXISTS SubLinks that it is able to convert to semi or anti joins. This makes pull_up_sublinks() a shade more complex, but the gain in semantic clarity is worth it. I still have more to do in this area to address the previously-discussed problems, but this commit in itself fixes at least one bug in HEAD, as shown by added regression test case.
2009-02-24 22:30:38 -05:00
extern JoinExpr *convert_ANY_sublink_to_join(PlannerInfo *root,
8.4 pgindent run, with new combined Linux/FreeBSD/MinGW typedef list provided by Andrew.
2009-06-11 10:49:15 -04:00
SubLink *sublink,
Relids available_rels);
Get rid of the rather fuzzily defined FlattenedSubLink node type in favor of making pull_up_sublinks() construct a full-blown JoinExpr tree representation of IN/EXISTS SubLinks that it is able to convert to semi or anti joins. This makes pull_up_sublinks() a shade more complex, but the gain in semantic clarity is worth it. I still have more to do in this area to address the previously-discussed problems, but this commit in itself fixes at least one bug in HEAD, as shown by added regression test case.
2009-02-24 22:30:38 -05:00
extern JoinExpr *convert_EXISTS_sublink_to_join(PlannerInfo *root,
8.4 pgindent run, with new combined Linux/FreeBSD/MinGW typedef list provided by Andrew.
2009-06-11 10:49:15 -04:00
SubLink *sublink,
bool under_not,
Relids available_rels);
Get rid of some old and crufty global variables in the planner. When this code was last gone over, there wasn't really any alternative to globals because we didn't have the PlannerInfo struct being passed all through the planner code. Now that we do, we can restructure things to avoid non-reentrancy. I'm fooling with this because otherwise I'd have had to add another global variable for the planned compact range table list.
2007-02-19 02:03:34 -05:00
extern Node *SS_replace_correlation_vars(PlannerInfo *root, Node *expr);
extern Node *SS_process_sublinks(PlannerInfo *root, Node *expr, bool isQual);
Tighten up SS_finalize_plan's computation of valid_params to exclude Params of the current query level that aren't in fact output parameters of the current initPlans. (This means, for example, output parameters of regular subplans.) To make this work correctly for output parameters coming from sibling initplans requires rejiggering the API of SS_finalize_plan just a bit: we need the siblings to be visible to it, rather than hidden as SS_make_initplan_from_plan had been doing. This is really part of my response to bug #4290, but I concluded this part probably shouldn't be back-patched, since all that it's doing is to make a debugging cross-check tighter.
2008-07-09 22:14:03 -04:00
extern void SS_finalize_plan(PlannerInfo *root, Plan *plan,
8.4 pgindent run, with new combined Linux/FreeBSD/MinGW typedef list provided by Andrew.
2009-06-11 10:49:15 -04:00
bool attach_initplans);
Remove planner's private fields from Query struct, and put them into a new PlannerInfo struct, which is passed around instead of the bare Query in all the planning code. This commit is essentially just a code-beautification exercise, but it does open the door to making larger changes to the planner data structures without having to muck with the widely-known Query struct.
2005-06-05 18:32:58 -04:00
extern Param *SS_make_initplan_from_plan(PlannerInfo *root, Plan *plan,
Standard pgindent run for 8.1.
2005-10-14 22:49:52 -04:00
Oid resulttype, int32 resulttypmod);
Make NestLoop plan nodes pass outer-relation variables into their inner relation using the general PARAM_EXEC executor parameter mechanism, rather than the ad-hoc kluge of passing the outer tuple down through ExecReScan. The previous method was hard to understand and could never be extended to handle parameters coming from multiple join levels. This patch doesn't change the set of possible plans nor have any significant performance effect, but it's necessary infrastructure for future generalization of the concept of an inner indexscan plan. ExecReScan's second parameter is now unused, so it's removed.
2010-07-12 13:01:06 -04:00
extern Param *assign_nestloop_param(PlannerInfo *root, Var *var);
Re-implement EvalPlanQual processing to improve its performance and eliminate a lot of strange behaviors that occurred in join cases. We now identify the "current" row for every joined relation in UPDATE, DELETE, and SELECT FOR UPDATE/SHARE queries. If an EvalPlanQual recheck is necessary, we jam the appropriate row into each scan node in the rechecking plan, forcing it to emit only that one row. The former behavior could rescan the whole of each joined relation for each recheck, which was terrible for performance, and what's much worse could result in duplicated output tuples. Also, the original implementation of EvalPlanQual could not re-use the recheck execution tree --- it had to go through a full executor init and shutdown for every row to be tested. To avoid this overhead, I've associated a special runtime Param with each LockRows or ModifyTable plan node, and arranged to make every scan node below such a node depend on that Param. Thus, by signaling a change in that Param, the EPQ machinery can just rescan the already-built test plan. This patch also adds a prohibition on set-returning functions in the targetlist of SELECT FOR UPDATE/SHARE. This is needed to avoid the duplicate-output-tuple problem. It seems fairly reasonable since the other restrictions on SELECT FOR UPDATE are meant to ensure that there is a unique correspondence between source tuples and result tuples, which an output SRF destroys as much as anything else does.
2009-10-25 22:26:45 -04:00
extern int SS_assign_special_param(PlannerInfo *root);
Another pgindent run. Fixes enum indenting, and improves #endif spacing. Also adds space for one-line comments.
2001-10-28 01:26:15 -05:00
New pgindent run with fixes suggested by Tom. Patch manually reviewed, initdb/regression tests pass.
2001-11-05 12:46:40 -05:00
#endif /* SUBSELECT_H */
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