aboutsummaryrefslogtreecommitdiff
path: root/src/include/optimizer/subselect.h
Commit message (Collapse)AuthorAge
* Convert 'x IN (VALUES ...)' to 'x = ANY ...' then appropriateAlexander Korotkov2025-04-04
| | | | | | | | | | | | | | | | | | | | | | | | | | This commit implements the automatic conversion of 'x IN (VALUES ...)' into ScalarArrayOpExpr. That simplifies the query tree, eliminating the appearance of an unnecessary join. Since VALUES describes a relational table, and the value of such a list is a table row, the optimizer will likely face an underestimation problem due to the inability to estimate cardinality through MCV statistics. The cardinality evaluation mechanism can work with the array inclusion check operation. If the array is small enough (< 100 elements), it will perform a statistical evaluation element by element. We perform the transformation in the convert_ANY_sublink_to_join() if VALUES RTE is proper and the transformation is convertible. The conversion is only possible for operations on scalar values, not rows. Also, we currently support the transformation only when it ends up with a constant array. Otherwise, the evaluation of non-hashed SAOP might be slower than the corresponding Hash Join with VALUES. Discussion: https://postgr.es/m/0184212d-1248-4f1f-a42d-f5cb1c1976d2%40tantorlabs.com Author: Alena Rybakina <a.rybakina@postgrespro.ru> Author: Andrei Lepikhov <lepihov@gmail.com> Reviewed-by: Ivan Kush <ivan.kush@tantorlabs.com> Reviewed-by: Alexander Korotkov <aekorotkov@gmail.com>
* Update copyright for 2025Bruce Momjian2025-01-01
| | | | Backpatch-through: 13
* Update copyright for 2024Bruce Momjian2024-01-03
| | | | | | | | Reported-by: Michael Paquier Discussion: https://postgr.es/m/ZZKTDPxBBMt3C0J9@paquier.xyz Backpatch-through: 12
* Allow plan nodes with initPlans to be considered parallel-safe.Tom Lane2023-07-14
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | If the plan itself is parallel-safe, and the initPlans are too, there's no reason anymore to prevent the plan from being marked parallel-safe. That restriction (dating to commit ab77a5a45) was really a special case of the fact that we couldn't transmit subplans to parallel workers at all. We fixed that in commit 5e6d8d2bb and follow-ons, but this case never got addressed. We still forbid attaching initPlans to a Gather node that's inserted pursuant to debug_parallel_query = regress. That's because, when we hide the Gather from EXPLAIN output, we'd hide the initPlans too, causing cosmetic regression diffs. It seems inadvisable to kluge EXPLAIN to the extent required to make the output look the same, so just don't do it in that case. Along the way, this also takes care of some sloppiness about updating path costs to match when we move initplans from one place to another during createplan.c and setrefs.c. Since all the planning decisions are already made by that point, this is just cosmetic; but it seems good to keep EXPLAIN output consistent with where the initplans are. The diff in query_planner() might be worth remarking on. I found that one because after fixing things to allow parallel-safe initplans, one partition_prune test case changed plans (as shown in the patch) --- but only when debug_parallel_query was active. The reason proved to be that we only bothered to mark Result nodes as potentially parallel-safe when debug_parallel_query is on. This neglects the fact that parallel-safety may be of interest for a sub-query even though the Result itself doesn't parallelize. Discussion: https://postgr.es/m/1129530.1681317832@sss.pgh.pa.us
* Update copyright for 2023Bruce Momjian2023-01-02
| | | | Backpatch-through: 11
* Update copyright for 2022Bruce Momjian2022-01-07
| | | | Backpatch-through: 10
* Update copyright for 2021Bruce Momjian2021-01-02
| | | | Backpatch-through: 9.5
* Update copyrights for 2020Bruce Momjian2020-01-01
| | | | Backpatch-through: update all files in master, backpatch legal files through 9.4
* Phase 2 pgindent run for v12.Tom Lane2019-05-22
| | | | | | | | | Switch to 2.1 version of pg_bsd_indent. This formats multiline function declarations "correctly", that is with additional lines of parameter declarations indented to match where the first line's left parenthesis is. Discussion: https://postgr.es/m/CAEepm=0P3FeTXRcU5B2W3jv3PgRVZ-kGUXLGfd42FFhUROO3ug@mail.gmail.com
* Rename nodes/relation.h to nodes/pathnodes.h.Tom Lane2019-01-29
| | | | | | | | | | | | | The old name of this file was never a very good indication of what it was for. Now that there's also access/relation.h, we have a potential confusion hazard as well, so let's rename it to something more apropos. Per discussion, "pathnodes.h" is reasonable, since a good fraction of the file is Path node definitions. While at it, tweak a couple of other headers that were gratuitously importing relation.h into modules that don't need it. Discussion: https://postgr.es/m/7719.1548688728@sss.pgh.pa.us
* Avoid sharing PARAM_EXEC slots between different levels of NestLoop.Tom Lane2019-01-11
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Up to now, createplan.c attempted to share PARAM_EXEC slots for NestLoopParams across different plan levels, if the same underlying Var was being fed down to different righthand-side subplan trees by different NestLoops. This was, I think, more of an artifact of using subselect.c's PlannerParamItem infrastructure than an explicit design goal, but anyway that was the end result. This works well enough as long as the plan tree is executing synchronously, but the feature whereby Gather can execute the parallelized subplan locally breaks it. An upper NestLoop node might execute for a row retrieved from a parallel worker, and assign a value for a PARAM_EXEC slot from that row, while the leader's copy of the parallelized subplan is suspended with a different active value of the row the Var comes from. When control eventually returns to the leader's subplan, it gets the wrong answers if the same PARAM_EXEC slot is being used within the subplan, as reported in bug #15577 from Bartosz Polnik. This is pretty reminiscent of the problem fixed in commit 46c508fbc, and the proper fix seems to be the same: don't try to share PARAM_EXEC slots across different levels of controlling NestLoop nodes. This requires decoupling NestLoopParam handling from PlannerParamItem handling, although the logic remains somewhat similar. To avoid bizarre division of labor between subselect.c and createplan.c, I decided to move all the param-slot-assignment logic for both cases out of those files and put it into a new file paramassign.c. Hopefully it's a bit better documented now, too. A regression test case for this might be nice, but we don't know a test case that triggers the problem with a suitably small amount of data. Back-patch to 9.6 where we added Gather nodes. It's conceivable that related problems exist in older branches; but without some evidence for that, I'll leave the older branches alone. Discussion: https://postgr.es/m/15577-ca61ab18904af852@postgresql.org
* Update copyright for 2019Bruce Momjian2019-01-02
| | | | Backpatch-through: certain files through 9.4
* Update copyright for 2018Bruce Momjian2018-01-02
| | | | Backpatch-through: certain files through 9.3
* Phase 2 of pgindent updates.Tom Lane2017-06-21
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Change pg_bsd_indent to follow upstream rules for placement of comments to the right of code, and remove pgindent hack that caused comments following #endif to not obey the general rule. Commit e3860ffa4dd0dad0dd9eea4be9cc1412373a8c89 wasn't actually using the published version of pg_bsd_indent, but a hacked-up version that tried to minimize the amount of movement of comments to the right of code. The situation of interest is where such a comment has to be moved to the right of its default placement at column 33 because there's code there. BSD indent has always moved right in units of tab stops in such cases --- but in the previous incarnation, indent was working in 8-space tab stops, while now it knows we use 4-space tabs. So the net result is that in about half the cases, such comments are placed one tab stop left of before. This is better all around: it leaves more room on the line for comment text, and it means that in such cases the comment uniformly starts at the next 4-space tab stop after the code, rather than sometimes one and sometimes two tabs after. Also, ensure that comments following #endif are indented the same as comments following other preprocessor commands such as #else. That inconsistency turns out to have been self-inflicted damage from a poorly-thought-through post-indent "fixup" in pgindent. This patch is much less interesting than the first round of indent changes, but also bulkier, so I thought it best to separate the effects. Discussion: https://postgr.es/m/E1dAmxK-0006EE-1r@gemulon.postgresql.org Discussion: https://postgr.es/m/30527.1495162840@sss.pgh.pa.us
* Update copyright via script for 2017Bruce Momjian2017-01-03
|
* Make the upper part of the planner work by generating and comparing Paths.Tom Lane2016-03-07
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | I've been saying we needed to do this for more than five years, and here it finally is. This patch removes the ever-growing tangle of spaghetti logic that grouping_planner() used to use to try to identify the best plan for post-scan/join query steps. Now, there is (nearly) independent consideration of each execution step, and entirely separate construction of Paths to represent each of the possible ways to do that step. We choose the best Path or set of Paths using the same add_path() logic that's been used inside query_planner() for years. In addition, this patch removes the old restriction that subquery_planner() could return only a single Plan. It now returns a RelOptInfo containing a set of Paths, just as query_planner() does, and the parent query level can use each of those Paths as the basis of a SubqueryScanPath at its level. This allows finding some optimizations that we missed before, wherein a subquery was capable of returning presorted data and thereby avoiding a sort in the parent level, making the overall cost cheaper even though delivering sorted output was not the cheapest plan for the subquery in isolation. (A couple of regression test outputs change in consequence of that. However, there is very little change in visible planner behavior overall, because the point of this patch is not to get immediate planning benefits but to create the infrastructure for future improvements.) There is a great deal left to do here. This patch unblocks a lot of planner work that was basically impractical in the old code structure, such as allowing FDWs to implement remote aggregation, or rewriting plan_set_operations() to allow consideration of multiple implementation orders for set operations. (The latter will likely require a full rewrite of plan_set_operations(); what I've done here is only to fix it to return Paths not Plans.) I have also left unfinished some localized refactoring in createplan.c and planner.c, because it was not necessary to get this patch to a working state. Thanks to Robert Haas, David Rowley, and Amit Kapila for review.
* Update copyright for 2016Bruce Momjian2016-01-02
| | | | Backpatch certain files through 9.1
* Postpone extParam/allParam calculations until the very end of planning.Tom Lane2015-08-11
| | | | | | | | | | | | | | | | | | | | | | | | Until now we computed these Param ID sets at the end of subquery_planner, but that approach depends on subquery_planner returning a concrete Plan tree. We would like to switch over to returning one or more Paths for a subquery, and in that representation the necessary details aren't fully fleshed out (not to mention that we don't really want to do this work for Paths that end up getting discarded). Hence, refactor so that we can compute the param ID sets at the end of planning, just before set_plan_references is run. The main change necessary to make this work is that we need to capture the set of outer-level Param IDs available to the current query level before exiting subquery_planner, since the outer levels' plan_params lists are transient. (That's not going to pose a problem for returning Paths, since all the work involved in producing that data is part of expression preprocessing, which will continue to happen before Paths are produced.) On the plus side, this change gets rid of several existing kluges. Eventually I'd like to get rid of SS_finalize_plan altogether in favor of doing this work during set_plan_references, but that will require some complex rejiggering because SS_finalize_plan needs to visit subplans and initplans before the main plan. So leave that idea for another day.
* Update copyright for 2015Bruce Momjian2015-01-06
| | | | Backpatch certain files through 9.0
* Update copyright for 2014Bruce Momjian2014-01-07
| | | | | Update all files in head, and files COPYRIGHT and legal.sgml in all back branches.
* Update copyrights for 2013Bruce Momjian2013-01-01
| | | | | Fully update git head, and update back branches in ./COPYRIGHT and legal.sgml files.
* Run pgindent on 9.2 source tree in preparation for first 9.3Bruce Momjian2012-06-10
| | | | commit-fest.
* Update copyright notices for year 2012.Bruce Momjian2012-01-01
|
* Fix handling of PlaceHolderVars in nestloop parameter management.Tom Lane2011-11-03
| | | | | | | | | | | | | If we use a PlaceHolderVar from the outer relation in an inner indexscan, we need to reference the PlaceHolderVar as such as the value to be passed in from the outer relation. The previous code effectively tried to reconstruct the PHV from its component expression, which doesn't work since (a) the Vars therein aren't necessarily bubbled up far enough, and (b) it would be the wrong semantics anyway because of the possibility that the PHV is supposed to have gone to null at some point before the current join. Point (a) led to "variable not found in subplan target list" planner errors, but point (b) would have led to silently wrong answers. Per report from Roger Niederland.
* pgindent run before PG 9.1 beta 1.Bruce Momjian2011-04-10
|
* Per-column collation supportPeter Eisentraut2011-02-08
| | | | | | | | This adds collation support for columns and domains, a COLLATE clause to override it per expression, and B-tree index support. Peter Eisentraut reviewed by Pavel Stehule, Itagaki Takahiro, Robert Haas, Noah Misch
* Stamp copyrights for year 2011.Bruce Momjian2011-01-01
|
* Remove cvs keywords from all files.Magnus Hagander2010-09-20
|
* Make NestLoop plan nodes pass outer-relation variables into their innerTom Lane2010-07-12
| | | | | | | | | | | | 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.
* Update copyright for the year 2010.Bruce Momjian2010-01-02
|
* Re-implement EvalPlanQual processing to improve its performance and eliminateTom Lane2009-10-26
| | | | | | | | | | | | | | | | | | | | | | | | | 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.
* 8.4 pgindent run, with new combined Linux/FreeBSD/MinGW typedef listBruce Momjian2009-06-11
| | | | provided by Andrew.
* Get rid of the rather fuzzily defined FlattenedSubLink node type in favor ofTom Lane2009-02-25
| | | | | | | | | 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.
* Update copyright for 2009.Bruce Momjian2009-01-01
|
* Implement SQL-standard WITH clauses, including WITH RECURSIVE.Tom Lane2008-10-04
| | | | | | | | | | | | | 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
* Improve sublink pullup code to handle ANY/EXISTS sublinks that are at topTom Lane2008-08-17
| | | | | | | | | | | | | level of a JOIN/ON clause, not only at top level of WHERE. (However, we can't do this in an outer join's ON clause, unless the ANY/EXISTS refers only to the nullable side of the outer join, so that it can effectively be pushed down into the nullable side.) Per request from Kevin Grittner. In passing, fix a bug in the initial implementation of EXISTS pullup: it would Assert if the EXIST's WHERE clause used a join alias variable. Since we haven't yet flattened join aliases when this transformation happens, it's necessary to include join relids in the computed set of RHS relids.
* Implement SEMI and ANTI joins in the planner and executor. (Semijoins replaceTom Lane2008-08-14
| | | | | | | | | | | | | | the old JOIN_IN code, but antijoins are new functionality.) Teach the planner to convert appropriate EXISTS and NOT EXISTS subqueries into semi and anti joins respectively. Also, LEFT JOINs with suitable upper-level IS NULL filters are recognized as being anti joins. Unify the InClauseInfo and OuterJoinInfo infrastructure into "SpecialJoinInfo". With that change, it becomes possible to associate a SpecialJoinInfo with every join attempt, which permits some cleanup of join selectivity estimation. That needs to be taken much further than this patch does, but the next step is to change the API for oprjoin selectivity functions, which seems like material for a separate patch. So for the moment the output size estimates for semi and especially anti joins are quite bogus.
* Tighten up SS_finalize_plan's computation of valid_params to exclude Params ofTom Lane2008-07-10
| | | | | | | | | | | 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.
* Update copyrights in source tree to 2008.Bruce Momjian2008-01-01
|
* Get rid of some old and crufty global variables in the planner. WhenTom Lane2007-02-19
| | | | | | | | | 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.
* Update CVS HEAD for 2007 copyright. Back branches are typically notBruce Momjian2007-01-05
| | | | back-stamped for this.
* Update copyright for 2006. Update scripts.Bruce Momjian2006-03-05
|
* Standard pgindent run for 8.1.Bruce Momjian2005-10-15
|
* Remove planner's private fields from Query struct, and put them intoTom Lane2005-06-05
| | | | | | | | 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.
* Create the planner mechanism for optimizing simple MIN and MAX queriesTom Lane2005-04-11
| | | | | | into indexscans on matching indexes. For the moment, it only handles int4 and text datatypes; next step is to add a column to pg_aggregate so that all MIN/MAX aggregates can be handled. Per my recent proposal.
* Tag appropriate files for rc3PostgreSQL Daemon2004-12-31
| | | | | | | | Also performed an initial run through of upgrading our Copyright date to extend to 2005 ... first run here was very simple ... change everything where: grep 1996-2004 && the word 'Copyright' ... scanned through the generated list with 'less' first, and after, to make sure that I only picked up the right entries ...
* Update copyright to 2004.Bruce Momjian2004-08-29
|
* make sure the $Id tags are converted to $PostgreSQL as well ...PostgreSQL Daemon2003-11-29
|
* Update copyrights to 2003.Bruce Momjian2003-08-04
|
* Implement outer-level aggregates to conform to the SQL spec, withTom Lane2003-06-06
| | | | | | | | extensions to support our historical behavior. An aggregate belongs to the closest query level of any of the variables in its argument, or the current query level if there are no variables (e.g., COUNT(*)). The implementation involves adding an agglevelsup field to Aggref, and treating outer aggregates like outer variables at planning time.