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path: root/src/backend/optimizer/plan/planagg.c
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* Split tuple struct defs from htup.h to htup_details.hAlvaro Herrera2012-08-30
| | | | | | | | | | | | This reduces unnecessary exposure of other headers through htup.h, which is very widely included by many files. I have chosen to move the function prototypes to the new file as well, because that means htup.h no longer needs to include tupdesc.h. In itself this doesn't have much effect in indirect inclusion of tupdesc.h throughout the tree, because it's also required by execnodes.h; but it's something to explore in the future, and it seemed best to do the htup.h change now while I'm busy with it.
* Fix up planner infrastructure to support LATERAL properly.Tom Lane2012-08-26
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch takes care of a number of problems having to do with failure to choose valid join orders and incorrect handling of lateral references pulled up from subqueries. Notable changes: * Add a LateralJoinInfo data structure similar to SpecialJoinInfo, to represent join ordering constraints created by lateral references. (I first considered extending the SpecialJoinInfo structure, but the semantics are different enough that a separate data structure seems better.) Extend join_is_legal() and related functions to prevent trying to form unworkable joins, and to ensure that we will consider joins that satisfy lateral references even if the joins would be clauseless. * Fill in the infrastructure needed for the last few types of relation scan paths to support parameterization. We'd have wanted this eventually anyway, but it is necessary now because a relation that gets pulled up out of a UNION ALL subquery may acquire a reltargetlist containing lateral references, meaning that its paths *have* to be parameterized whether or not we have any code that can push join quals down into the scan. * Compute data about lateral references early in query_planner(), and save in RelOptInfo nodes, to avoid repetitive calculations later. * Assorted corner-case bug fixes. There's probably still some bugs left, but this is a lot closer to being real than it was before.
* Account for SRFs in targetlists in planner rowcount estimates.Tom Lane2012-07-21
| | | | | | | | | | | | | We made use of the ROWS estimate for set-returning functions used in FROM, but not for those used in SELECT targetlists; which is a bit of an oversight considering there are common usages that require the latter approach. Improve that. (I had initially thought it might be worth folding this into cost_qual_eval, but after investigation concluded that that wouldn't be very helpful, so just do it separately.) Per complaint from David Johnston. Back-patch to 9.2, but not further, for fear of destabilizing plan choices in existing releases.
* Run pgindent on 9.2 source tree in preparation for first 9.3Bruce Momjian2012-06-10
| | | | commit-fest.
* Revisit handling of UNION ALL subqueries with non-Var output columns.Tom Lane2012-03-16
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | In commit 57664ed25e5dea117158a2e663c29e60b3546e1c I tried to fix a bug reported by Teodor Sigaev by making non-simple-Var output columns distinct (by wrapping their expressions with dummy PlaceHolderVar nodes). This did not work too well. Commit b28ffd0fcc583c1811e5295279e7d4366c3cae6c fixed some ensuing problems with matching to child indexes, but per a recent report from Claus Stadler, constraint exclusion of UNION ALL subqueries was still broken, because constant-simplification didn't handle the injected PlaceHolderVars well either. On reflection, the original patch was quite misguided: there is no reason to expect that EquivalenceClass child members will be distinct. So instead of trying to make them so, we should ensure that we can cope with the situation when they're not. Accordingly, this patch reverts the code changes in the above-mentioned commits (though the regression test cases they added stay). Instead, I've added assorted defenses to make sure that duplicate EC child members don't cause any problems. Teodor's original problem ("MergeAppend child's targetlist doesn't match MergeAppend") is addressed more directly by revising prepare_sort_from_pathkeys to let the parent MergeAppend's sort list guide creation of each child's sort list. In passing, get rid of add_sort_column; as far as I can tell, testing for duplicate sort keys at this stage is dead code. Certainly it doesn't trigger often enough to be worth expending cycles on in ordinary queries. And keeping the test would've greatly complicated the new logic in prepare_sort_from_pathkeys, because comparing pathkey list entries against a previous output array requires that we not skip any entries in the list. Back-patch to 9.1, like the previous patches. The only known issue in this area that wasn't caused by the ill-advised previous patches was the MergeAppend planning failure, which of course is not relevant before 9.1. It's possible that we need some of the new defenses against duplicate child EC entries in older branches, but until there's some clear evidence of that I'm going to refrain from back-patching further.
* Update copyright notices for year 2012.Bruce Momjian2012-01-01
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* Improve cost estimation for aggregates and window functions.Tom Lane2011-04-24
| | | | | | | | | | | | | | | | The previous coding failed to account properly for the costs of evaluating the input expressions of aggregates and window functions, as seen in a recent gripe from Claudio Freire. (I said at the time that it wasn't counting these costs at all; but on closer inspection, it was effectively charging these costs once per output tuple. That is completely wrong for aggregates, and not exactly right for window functions either.) There was also a hard-wired assumption that aggregates and window functions had procost 1.0, which is now fixed to respect the actual cataloged costs. The costing of WindowAgg is still pretty bogus, since it doesn't try to estimate the effects of spilling data to disk, but that seems like a separate issue.
* pgindent run before PG 9.1 beta 1.Bruce Momjian2011-04-10
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* Pass collation to makeConst() instead of looking it up internally.Tom Lane2011-03-25
| | | | | | | | | In nearly all cases, the caller already knows the correct collation, and in a number of places, the value the caller has handy is more correct than the default for the type would be. (In particular, this patch makes it significantly less likely that eval_const_expressions will result in changing the exposed collation of an expression.) So an internal lookup is both expensive and wrong.
* Reimplement planner's handling of MIN/MAX aggregate optimization (again).Tom Lane2011-03-22
| | | | | | | | | | | | | | Instead of playing cute games with pathkeys, just build a direct representation of the intended sub-select, and feed it through query_planner to get a Path for the index access. This is a bit slower than 9.1's previous method, since we'll duplicate most of the overhead of query_planner; but since the whole optimization only applies to rather simple single-table queries, that probably won't be much of a problem in practice. The advantage is that we get to do the right thing when there's a partial index that needs the implicit IS NOT NULL clause to be usable. Also, although this makes planagg.c be a bit more closely tied to the ordering of operations in grouping_planner, we can get rid of some coupling to lower-level parts of the planner. Per complaint from Marti Raudsepp.
* 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
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* Reimplement planner's handling of MIN/MAX aggregate optimization.Tom Lane2010-11-04
| | | | | | | | | | | | | | | | | | | | | | Per my recent proposal, get rid of all the direct inspection of indexes and manual generation of paths in planagg.c. Instead, set up EquivalenceClasses for the aggregate argument expressions, and let the regular path generation logic deal with creating paths that can satisfy those sort orders. This makes planagg.c a bit more visible to the rest of the planner than it was originally, but the approach is basically a lot cleaner than before. A major advantage of doing it this way is that we get MIN/MAX optimization on inheritance trees (using MergeAppend of indexscans) practically for free, whereas in the old way we'd have had to add a whole lot more duplicative logic. One small disadvantage of this approach is that MIN/MAX aggregates can no longer exploit partial indexes having an "x IS NOT NULL" predicate, unless that restriction or something that implies it is specified in the query. The previous implementation was able to use the added "x IS NOT NULL" condition as an extra predicate proof condition, but in this version we rely entirely on indexes that are considered usable by the main planning process. That seems a fair tradeoff for the simplicity and functionality gained.
* Provide hashing support for arrays.Tom Lane2010-10-30
| | | | | | | | | | | | | | | | | | | | | The core of this patch is hash_array() and associated typcache infrastructure, which works just about exactly like the existing support for array comparison. In addition I did some work to ensure that the planner won't think that an array type is hashable unless its element type is hashable, and similarly for sorting. This includes adding a datatype parameter to op_hashjoinable and op_mergejoinable, and adding an explicit "hashable" flag to SortGroupClause. The lack of a cross-check on the element type was a pre-existing bug in mergejoin support --- but it didn't matter so much before, because if you couldn't sort the element type there wasn't any good alternative to failing anyhow. Now that we have the alternative of hashing the array type, there are cases where we can avoid a failure by being picky at the planner stage, so it's time to be picky. The issue of exactly how to combine the per-element hash values to produce an array hash is still open for discussion, but the rest of this is pretty solid, so I'll commit it as-is.
* Remove cvs keywords from all files.Magnus Hagander2010-09-20
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* pgindent run for 9.0, second runBruce Momjian2010-07-06
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* When adding a "target IS NOT NULL" indexqual to the plan for an index-optimizedTom Lane2010-05-10
| | | | | | | | | MIN or MAX, we must take care to insert the added qual in a legal place among the existing indexquals, if any. The btree index AM requires the quals to appear in index-column order. We didn't have to worry about this before because "target IS NOT NULL" was just treated as a plain scan filter condition; but as of 9.0 it can be an index qual and then it has to follow the rule. Per report from Ian Barwick.
* Wrap calls to SearchSysCache and related functions using macros.Robert Haas2010-02-14
| | | | | | | | | | | | The purpose of this change is to eliminate the need for every caller of SearchSysCache, SearchSysCacheCopy, SearchSysCacheExists, GetSysCacheOid, and SearchSysCacheList to know the maximum number of allowable keys for a syscache entry (currently 4). This will make it far easier to increase the maximum number of keys in a future release should we choose to do so, and it makes the code shorter, too. Design and review by Tom Lane.
* Update copyright for the year 2010.Bruce Momjian2010-01-02
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* Add an "argisrow" field to NullTest nodes, following a plan made way back inTom Lane2010-01-01
| | | | | | 8.2beta but never carried out. This avoids repetitive tests of whether the argument is of scalar or composite type. Also, be a bit more paranoid about composite arguments in some places where we previously weren't checking.
* Support "x IS NOT NULL" clauses as indexscan conditions. This turns outTom Lane2010-01-01
| | | | | | | | | | | to be just a minor extension of the previous patch that made "x IS NULL" indexable, because we can treat the IS NOT NULL condition as if it were "x < NULL" or "x > NULL" (depending on the index's NULLS FIRST/LAST option), just like IS NULL is treated like "x = NULL". Aside from any possible usefulness in its own right, this is an important improvement for index-optimized MAX/MIN aggregates: it is now reliably possible to get a column's min or max value cheaply, even when there are a lot of nulls cluttering the interesting end of the index.
* Support ORDER BY within aggregate function calls, at long last providing aTom Lane2009-12-15
| | | | | | | | | | | | | non-kluge method for controlling the order in which values are fed to an aggregate function. At the same time eliminate the old implementation restriction that DISTINCT was only supported for single-argument aggregates. Possibly release-notable behavioral change: formerly, agg(DISTINCT x) dropped null values of x unconditionally. Now, it does so only if the agg transition function is strict; otherwise nulls are treated as DISTINCT normally would, ie, you get one copy. Andrew Gierth, reviewed by Hitoshi Harada
* 8.4 pgindent run, with new combined Linux/FreeBSD/MinGW typedef listBruce Momjian2009-06-11
| | | | provided by Andrew.
* Update copyright for 2009.Bruce Momjian2009-01-01
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* Support window functions a la SQL:2008.Tom Lane2008-12-28
| | | | Hitoshi Harada, with some kibitzing from Heikki and Tom.
* Move exprType(), exprTypmod(), expression_tree_walker(), and related routinesTom Lane2008-08-25
| | | | | | into nodes/nodeFuncs, so as to reduce wanton cross-subsystem #includes inside the backend. There's probably more that should be done along this line, but this is a start anyway.
* Rearrange the querytree representation of ORDER BY/GROUP BY/DISTINCT itemsTom Lane2008-08-02
| | | | | | | | | | | | | | | | | | | | | | | | | | | as per my recent proposal: 1. Fold SortClause and GroupClause into a single node type SortGroupClause. We were already relying on them to be struct-equivalent, so using two node tags wasn't accomplishing much except to get in the way of comparing items with equal(). 2. Add an "eqop" field to SortGroupClause to carry the associated equality operator. This is cheap for the parser to get at the same time it's looking up the sort operator, and storing it eliminates the need for repeated not-so-cheap lookups during planning. In future this will also let us represent GROUP/DISTINCT operations on datatypes that have hash opclasses but no btree opclasses (ie, they have equality but no natural sort order). The previous representation simply didn't work for that, since its only indicator of comparison semantics was a sort operator. 3. Add a hasDistinctOn boolean to struct Query to explicitly record whether the distinctClause came from DISTINCT or DISTINCT ON. This allows removing some complicated and not 100% bulletproof code that attempted to figure that out from the distinctClause alone. This patch doesn't in itself create any new capability, but it's necessary infrastructure for future attempts to use hash-based grouping for DISTINCT and UNION/INTERSECT/EXCEPT.
* 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.
* Fix mis-calculation of extParam/allParam sets for plan nodes, as seen inTom Lane2008-07-10
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | bug #4290. The fundamental bug is that masking extParam by outer_params, as finalize_plan had been doing, caused us to lose the information that an initPlan depended on the output of a sibling initPlan. On reflection the best thing to do seemed to be not to try to adjust outer_params for this case but get rid of it entirely. The only thing it was really doing for us was to filter out param IDs associated with SubPlan nodes, and that can be done (with greater accuracy) while processing individual SubPlan nodes in finalize_primnode. This approach was vindicated by the discovery that the masking method was hiding a second bug: SS_finalize_plan failed to remove extParam bits for initPlan output params that were referenced in the main plan tree (it only got rid of those referenced by other initPlans). It's not clear that this caused any real problems, given the limited use of extParam by the executor, but it's certainly not what was intended. I originally thought that there was also a problem with needing to include indirect dependencies on external params in initPlans' param sets, but it turns out that the executor handles this correctly so long as the depended-on initPlan is earlier in the initPlans list than the one using its output. That seems a bit of a fragile assumption, but it is true at the moment, so I just documented it in some code comments rather than making what would be rather invasive changes to remove the assumption. Back-patch to 8.1. Previous versions don't have the case of initPlans referring to other initPlans' outputs, so while the existing logic is still questionable for them, there are not any known bugs to be fixed. So I'll refrain from changing them for now.
* Improve our #include situation by moving pointer types away from theAlvaro Herrera2008-06-19
| | | | | | | corresponding struct definitions. This allows other headers to avoid including certain highly-loaded headers such as rel.h and relscan.h, instead using just relcache.h, heapam.h or genam.h, which are more lightweight and thus cause less unnecessary dependencies.
* Allow float8, int8, and related datatypes to be passed by value on machinesTom Lane2008-04-21
| | | | | | | | | | where Datum is 8 bytes wide. Since this will break old-style C functions (those still using version 0 calling convention) that have arguments or results of these types, provide a configure option to disable it and retain the old pass-by-reference behavior. Likewise, provide a configure option to disable the recently-committed float4 pass-by-value change. Zoltan Boszormenyi, plus configurability stuff by me.
* Apply my original fix for Taiki Yamaguchi's bug report about DISTINCT MAX().Tom Lane2008-03-31
| | | | Add some regression tests for plausible failures in this area.
* Update copyrights in source tree to 2008.Bruce Momjian2008-01-01
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* Fix build_minmax_path() to cope if an IS NULL clause turns up in theTom Lane2007-12-03
| | | | | | indexable-clauses list for a btree index. Formerly it just Asserted that all such clauses were opclauses, but that's no longer true in 8.3. Per bug #3796 from Matthias Schoeneich.
* pgindent run for 8.3.Bruce Momjian2007-11-15
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* Teach planagg.c that partial indexes specifying WHERE foo IS NOT NULL can beTom Lane2007-10-13
| | | | | | | | | used to perform MIN(foo) or MAX(foo), since we want to discard null rows in the indexscan anyway. (This would probably fall out for free if we were injecting the IS NOT NULL clause somewhere earlier, but given the current anatomy of the MIN/MAX optimization code we have to do it explicitly. Fortunately, very little added code is needed.) Per a discussion with Henk de Wit.
* Modify processing of DECLARE CURSOR and EXPLAIN so that they can resolve theTom Lane2007-04-27
| | | | | | | | | | | | | | types of unspecified parameters when submitted via extended query protocol. This worked in 8.2 but I had broken it during plancache changes. DECLARE CURSOR is now treated almost exactly like a plain SELECT through parse analysis, rewrite, and planning; only just before sending to the executor do we divert it away to ProcessUtility. This requires a special-case check in a number of places, but practically all of them were already special-casing SELECT INTO, so it's not too ugly. (Maybe it would be a good idea to merge the two by treating IntoClause as a form of utility statement? Not going to worry about that now, though.) That approach doesn't work for EXPLAIN, however, so for that I punted and used a klugy solution of running parse analysis an extra time if under extended query protocol.
* Some further performance tweaks for planning large inheritance trees thatTom Lane2007-04-21
| | | | | | | | are mostly excluded by constraints: do the CE test a bit earlier to save some adjust_appendrel_attrs() work on excluded children, and arrange to use array indexing rather than rt_fetch() to fetch RTEs in the main body of the planner. The latter is something I'd wanted to do for awhile anyway, but seeing list_nth_cell() as 35% of the runtime gets one's attention.
* Fix up the remaining places where the expression node structure would loseTom Lane2007-03-17
| | | | | | | | | | | | | | available information about the typmod of an expression; namely, Const, ArrayRef, ArrayExpr, and EXPR and ARRAY SubLinks. In the ArrayExpr and SubLink cases it wasn't really the data structure's fault, but exprTypmod() being lazy. This seems like a good idea in view of the expected increase in typmod usage from Teodor's work to allow user-defined types to have typmods. In particular this responds to the concerns we had about eliminating the special-purpose hack that exprTypmod() used to have for BPCHAR Consts. We can now tell whether or not such a Const has been cast to a specific length, and report or display properly if so. initdb forced due to changes in stored rules.
* Turn the rangetable used by the executor into a flat list, and avoid storingTom Lane2007-02-22
| | | | | | | | | | | | | | | | | useless substructure for its RangeTblEntry nodes. (I chose to keep using the same struct node type and just zero out the link fields for unneeded info, rather than making a separate ExecRangeTblEntry type --- it seemed too fragile to have two different rangetable representations.) Along the way, put subplans into a list in the toplevel PlannedStmt node, and have SubPlan nodes refer to them by list index instead of direct pointers. Vadim wanted to do that years ago, but I never understood what he was on about until now. It makes things a *whole* lot more robust, because we can stop worrying about duplicate processing of subplans during expression tree traversals. That's been a constant source of bugs, and it's finally gone. There are some consequent simplifications yet to be made, like not using a separate EState for subplans in the executor, but I'll tackle that later.
* Remove the Query structure from the executor's API. This allows us to stopTom Lane2007-02-20
| | | | | | | | | | | | | | | storing mostly-redundant Query trees in prepared statements, portals, etc. To replace Query, a new node type called PlannedStmt is inserted by the planner at the top of a completed plan tree; this carries just the fields of Query that are still needed at runtime. The statement lists kept in portals etc. now consist of intermixed PlannedStmt and bare utility-statement nodes --- no Query. This incidentally allows us to remove some fields from Query and Plan nodes that shouldn't have been there in the first place. Still to do: simplify the execution-time range table; at the moment the range table passed to the executor still contains Query trees for subqueries. initdb forced due to change of stored rules.
* 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.
* Fix a performance regression in 8.2: optimization of MIN/MAX into indexscansTom Lane2007-02-06
| | | | | | | had stopped working for tables buried inside views or sub-selects. This is because I had gotten rid of the simplify_jointree() preprocessing step, and optimize_minmax_aggregates() wasn't smart enough to deal with a non-canonical FromExpr. Per gripe from Bill Howe.
* Support ORDER BY ... NULLS FIRST/LAST, and add ASC/DESC/NULLS FIRST/NULLS LASTTom Lane2007-01-09
| | | | | | | | | | | | per-column options for btree indexes. The planner's support for this is still pretty rudimentary; it does not yet know how to plan mergejoins with nondefault ordering options. The documentation is pretty rudimentary, too. I'll work on improving that stuff later. Note incompatible change from prior behavior: ORDER BY ... USING will now be rejected if the operator is not a less-than or greater-than member of some btree opclass. This prevents less-than-sane behavior if an operator that doesn't actually define a proper sort ordering is selected.
* Update CVS HEAD for 2007 copyright. Back branches are typically notBruce Momjian2007-01-05
| | | | back-stamped for this.
* Restructure operator classes to allow improved handling of cross-data-typeTom Lane2006-12-23
| | | | | | | | | | | | | | | | cases. Operator classes now exist within "operator families". While most families are equivalent to a single class, related classes can be grouped into one family to represent the fact that they are semantically compatible. Cross-type operators are now naturally adjunct parts of a family, without having to wedge them into a particular opclass as we had done originally. This commit restructures the catalogs and cleans up enough of the fallout so that everything still works at least as well as before, but most of the work needed to actually improve the planner's behavior will come later. Also, there are not yet CREATE/DROP/ALTER OPERATOR FAMILY commands; the only way to create a new family right now is to allow CREATE OPERATOR CLASS to make one by default. I owe some more documentation work, too. But that can all be done in smaller pieces once this infrastructure is in place.
* pgindent run for 8.2.Bruce Momjian2006-10-04
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* Add INSERT/UPDATE/DELETE RETURNING, with basic docs and regression tests.Tom Lane2006-08-12
| | | | | | | | plpgsql support to come later. Along the way, convert execMain's SELECT INTO support into a DestReceiver, in order to eliminate some ugly special cases. Jonah Harris and Tom Lane
* Aggregate functions now support multiple input arguments. I also tookTom Lane2006-07-27
| | | | | | | | the opportunity to treat COUNT(*) as a zero-argument aggregate instead of the old hack that equated it to COUNT(1); this is materially cleaner (no more weird ANYOID cases) and ought to be at least a tiny bit faster. Original patch by Sergey Koposov; review, documentation, simple regression tests, pg_dump and psql support by moi.
* Code review for bigint-LIMIT patch. Fix missed planner dependency,Tom Lane2006-07-26
| | | | | | eliminate unnecessary code, force initdb because stored rules change (limit nodes are now supposed to be int8 not int4 expressions). Update comments and error messages, which still all said 'integer'.