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path: root/src/backend/optimizer/plan/createplan.c
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* Phase 2 of read-only-plans project: restructure expression-tree nodesTom Lane2002-12-12
| | | | | | | | | so that all executable expression nodes inherit from a common supertype Expr. This is somewhat of an exercise in code purity rather than any real functional advance, but getting rid of the extra Oper or Func node formerly used in each operator or function call should provide at least a little space and speed improvement. initdb forced by changes in stored-rules representation.
* Phase 1 of read-only-plans project: cause executor state nodes to pointTom Lane2002-12-05
| | | | | | | | | | to plan nodes, not vice-versa. All executor state nodes now inherit from struct PlanState. Copying of plan trees has been simplified by not storing a list of SubPlans in Plan nodes (eliminating duplicate links). The executor still needs such a list, but it can build it during ExecutorStart since it has to scan the plan tree anyway. No initdb forced since no stored-on-disk structures changed, but you will need a full recompile because of node-numbering changes.
* Be more realistic about plans involving Materialize nodes: take theirTom Lane2002-11-30
| | | | cost into account while planning.
* Upgrade planner and executor to allow multiple hash keys for a hash join,Tom Lane2002-11-30
| | | | | | instead of only one. This should speed up planning (only one hash path to consider for a given pair of relations) as well as allow more effective hashing, when there are multiple hashable joinclauses.
* Finish implementation of hashed aggregation. Add enable_hashagg GUCTom Lane2002-11-21
| | | | | | parameter to allow it to be forced off for comparison purposes. Add ORDER BY clauses to a bunch of regression test queries that will otherwise produce randomly-ordered output in the new regime.
* Add an at-least-marginally-plausible method of estimating the numberTom Lane2002-11-19
| | | | | | 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.
* Push qual clauses containing subplans to the back of the qual listTom Lane2002-11-15
| | | | at each plan node. Per gripe from Ross Reedstrom.
* Phase 2 of hashed-aggregation project. nodeAgg.c now knows how to doTom Lane2002-11-06
| | | | hashed aggregation, but there's not yet planner support for it.
* First phase of implementing hash-based grouping/aggregation. An AGG planTom Lane2002-11-06
| | | | | | | | | | | | | 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.
* Extend pg_cast castimplicit column to a three-way value; this allows usTom Lane2002-09-18
| | | | | | | | | | | | | | | | | | | | | | | | to be flexible about assignment casts without introducing ambiguity in operator/function resolution. Introduce a well-defined promotion hierarchy for numeric datatypes (int2->int4->int8->numeric->float4->float8). Change make_const to initially label numeric literals as int4, int8, or numeric (never float8 anymore). Explicitly mark Func and RelabelType nodes to indicate whether they came from a function call, explicit cast, or implicit cast; use this to do reverse-listing more accurately and without so many heuristics. Explicit casts to char, varchar, bit, varbit will truncate or pad without raising an error (the pre-7.2 behavior), while assigning to a column without any explicit cast will still raise an error for wrong-length data like 7.3. This more nearly follows the SQL spec than 7.2 behavior (we should be reporting a 'completion condition' in the explicit-cast cases, but we have no mechanism for that, so just do silent truncation). Fix some problems with enforcement of typmod for array elements; it didn't work at all in 'UPDATE ... SET array[n] = foo', for example. Provide a generalized array_length_coerce() function to replace the specialized per-array-type functions that used to be needed (and were missing for NUMERIC as well as all the datetime types). Add missing conversions int8<->float4, text<->numeric, oid<->int8. initdb forced.
* pgindent run.Bruce Momjian2002-09-04
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* Remove sys/types.h in files that include postgres.h, and hence c.h,Bruce Momjian2002-09-02
| | | | because c.h has sys/types.h.
* Update copyright to 2002.Bruce Momjian2002-06-20
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* Change set_plan_references and join_references to take an rtable ListTom Lane2002-05-18
| | | | | | | | 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.
* First pass at set-returning-functions in FROM, by Joe Conway withTom Lane2002-05-12
| | | | | | some kibitzing from Tom Lane. Not everything works yet, and there's no documentation or regression test, but let's commit this so Joe doesn't need to cope with tracking changes in so many files ...
* Second try at fixing join alias variables. Instead of attaching miscellaneousTom Lane2002-04-28
| | | | | | | | lists to join RTEs, attach a list of Vars and COALESCE expressions that will replace the join's alias variables during planning. This simplifies flatten_join_alias_vars while still making it easy to fix up varno references when transforming the query tree. Add regression test cases for interactions of subqueries with outer joins.
* Restructure representation of join alias variables. An explicit JOINTom Lane2002-03-12
| | | | | | | | | | | | | | | 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.
* Another pgindent run. Fixes enum indenting, and improves #endifBruce Momjian2001-10-28
| | | | spacing. Also adds space for one-line comments.
* pgindent run on all C files. Java run to follow. initdb/regressionBruce Momjian2001-10-25
| | | | tests pass.
* Produce slightly saner-looking EXPLAIN output for a Result node.Tom Lane2001-09-21
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* Restructure pg_opclass, pg_amop, and pg_amproc per previous discussions inTom Lane2001-08-21
| | | | | | | | | | | | | | | | | | | | pgsql-hackers. pg_opclass now has a row for each opclass supported by each index AM, not a row for each opclass name. This allows pg_opclass to show directly whether an AM supports an opclass, and furthermore makes it possible to store additional information about an opclass that might be AM-dependent. pg_opclass and pg_amop now store "lossy" and "haskeytype" information that we previously expected the user to remember to provide in CREATE INDEX commands. Lossiness is no longer an index-level property, but is associated with the use of a particular operator in a particular index opclass. Along the way, IndexSupportInitialize now uses the syscaches to retrieve pg_amop and pg_amproc entries. I find this reduces backend launch time by about ten percent, at the cost of a couple more special cases in catcache.c's IndexScanOK. Initial work by Oleg Bartunov and Teodor Sigaev, further hacking by Tom Lane. initdb forced.
* Further work on making use of new statistics in planner. Adjust APIsTom Lane2001-06-05
| | | | | | | | | 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).
* Modify optimizer data structures so that IndexOptInfo lists built forTom Lane2001-05-20
| | | | | | | | create_index_paths are not immediately discarded, but are available for subsequent planner work. This allows avoiding redundant syscache lookups in several places. Change interface to operator selectivity estimation procedures to allow faster and more flexible estimation. Initdb forced due to change of pg_proc entries for selectivity functions!
* Rewrite of planner statistics-gathering code. ANALYZE is now available asTom Lane2001-05-07
| | | | | | | | | | | | | | | | | a separate statement (though it can still be invoked as part of VACUUM, too). pg_statistic redesigned to be more flexible about what statistics are stored. ANALYZE now collects a list of several of the most common values, not just one, plus a histogram (not just the min and max values). Random sampling is used to make the process reasonably fast even on very large tables. The number of values and histogram bins collected is now user-settable via an ALTER TABLE command. There is more still to do; the new stats are not being used everywhere they could be in the planner. But the remaining changes for this project should be localized, and the behavior is already better than before. A not-very-related change is that sorting now makes use of btree comparison routines if it can find one, rather than invoking '<' twice.
* pgindent run. Make it all clean.Bruce Momjian2001-03-22
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* Change Copyright from PostgreSQL, Inc to PostgreSQL Global Development Group.Bruce Momjian2001-01-24
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* Compute reasonable cost and output-row-count estimates for LIMIT planTom Lane2000-12-23
| | | | nodes.
* Change SearchSysCache coding conventions so that a reference count isTom Lane2000-11-16
| | | | | | | maintained for each cache entry. A cache entry will not be freed until the matching ReleaseSysCache call has been executed. This eliminates worries about cache entries getting dropped while still in use. See my posting to pg-hackers of even date for more info.
* Restructure handling of inheritance queries so that they work with outerTom Lane2000-11-12
| | | | | | | | | | | | | | | | | 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.
* Re-implement LIMIT/OFFSET as a plan node type, instead of a hack inTom Lane2000-10-26
| | | | | | 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.
* Reimplementation of UNION/INTERSECT/EXCEPT. INTERSECT/EXCEPT now meet theTom Lane2000-10-05
| | | | | | | | | | | 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!
* Subselects in FROM clause, per ISO syntax: FROM (SELECT ...) [AS] alias.Tom Lane2000-09-29
| | | | | | | | | (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!
* First cut at full support for OUTER JOINs. There are still a few looseTom Lane2000-09-12
| | | | | ends to clean up (see my message of same date to pghackers), but mostly it works. INITDB REQUIRED!
* Clean up handling of variable-free qual clauses. System now does theTom Lane2000-08-13
| | | | | | | | | | right thing with variable-free clauses that contain noncachable functions, such as 'WHERE random() < 0.5' --- these are evaluated once per potential output tuple. Expressions that contain only Params are now candidates to be indexscan quals --- for example, 'var = ($1 + 1)' can now be indexed. Cope with RelabelType nodes atop potential indexscan variables --- this oversight prevents 7.0.* from recognizing some potentially indexscanable situations.
* First stage of reclaiming memory in executor by resetting short-termTom Lane2000-07-12
| | | | | | memory contexts. Currently, only leaks in expressions executed as quals or projections are handled. Clean up some old dead cruft in executor while at it --- unused fields in state nodes, that sort of thing.
* Reimplement nodeMaterial to use a temporary BufFile (or even memory, if theTom Lane2000-06-18
| | | | | | | | | | 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.
* Clean up #include's.Bruce Momjian2000-06-15
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* Mark functions as static and ifdef NOT_USED as appropriate.Bruce Momjian2000-06-08
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* Fix problem in which sloppily-coded test in ExecInitIndexScan wouldTom Lane2000-05-23
| | | | | | | | | | | | think that both sides of indexqual look like index keys. An example is create table inside (f1 float8 primary key); create table outside (g1 float8, g2 float8); select * from inside,outside where f1 = atan2(g1+1, g2); ERROR: ExecInitIndexScan: both left and right ops are rel-vars (note that failure is potentially platform-dependent). Solution is a cleanup I had had in mind to make anyway: functional index keys should be represented as Var nodes in the fixed indexqual, just like regular index keys.
* Ye-old pgindent run. Same 4-space tabs.Bruce Momjian2000-04-12
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* Fix extremely nasty little bug observed when a sub-SELECT appears inTom Lane2000-04-04
| | | | | | | | | | | | | | | | | | | | WHERE in a place where it can be part of a nestloop inner indexqual. As the code stood, it put the same physical sub-Plan node into both indxqual and indxqualorig of the IndexScan plan node. That confused later processing in the optimizer (which expected that tracing the subPlan list would visit each subplan node exactly once), and would probably have blown up in the executor if the planner hadn't choked first. Fix by making the 'fixed' indexqual be a complete deep copy of the original indexqual, rather than trying to share nodes below the topmost operator node. This had further ramifications though, because we were making the aforesaid list of sub-Plan nodes during SS_process_sublinks which is run before construction of the 'fixed' indexqual, meaning that the copy of the sub-Plan didn't show up in that list. Fix by rearranging logic so that the sub-Plan list is built by the final set_plan_references pass, not in SS_process_sublinks. This may sound like a mess, but it's actually a good deal cleaner now than it was before, because we are no longer dependent on the assumption that planning will never make a copy of a sub-Plan node.
* Repair logic flaw in cost estimator: cost_nestloop() was estimating CPUTom Lane2000-03-22
| | | | | | | | | | | | | costs using the inner path's parent->rows count as the number of tuples processed per inner scan iteration. This is wrong when we are using an inner indexscan with indexquals based on join clauses, because the rows count in a Relation node reflects the selectivity of the restriction clauses for that rel only. Upshot was that if join clause was very selective, we'd drastically overestimate the true cost of the join. Fix is to calculate correct output-rows estimate for an inner indexscan when the IndexPath node is created and save it in the path node. Change of path node doesn't require initdb, since path nodes don't appear in saved rules.
* Plug some more memory leaks in the planner. It still leaks like a sieve,Tom Lane2000-02-18
| | | | but this is as good as it'll get for this release...
* New cost model for planning, incorporating a penalty for random pageTom Lane2000-02-15
| | | | | | | | | | | | | | | | | | | | | | | | | 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.
* Repair planning bugs caused by my misguided removal of restrictinfo linkTom Lane2000-02-07
| | | | | | | | | | | fields in JoinPaths --- turns out that we do need that after all :-(. Also, rearrange planner so that only one RelOptInfo is created for a particular set of joined base relations, no matter how many different subsets of relations it can be created from. This saves memory and processing time compared to the old method of making a bunch of RelOptInfos and then removing the duplicates. Clean up the jointree iteration logic; not sure if it's better, but I sure find it more readable and plausible now, particularly for the case of 'bushy plans'.
* Make EXPLAIN results for Append, Group, Agg, Unique nodes more plausible.Tom Lane2000-02-03
| | | | | Group and Unique use an arbitrary assumption that there will be about 10% as many groups as input tuples --- perhaps someday we can refine this.
* Redesign DISTINCT ON as discussed in pgsql-sql 1/25/00: syntax is nowTom Lane2000-01-27
| | | | | | | | | | | | | 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...
* Add:Bruce Momjian2000-01-26
| | | | | | * Portions Copyright (c) 1996-2000, PostgreSQL, Inc to all files copyright Regents of Berkeley. Man, that's a lot of files.
* First cut at unifying regular selectivity estimation with indexscanTom Lane2000-01-23
| | | | selectivity estimation wasn't right. This is better...
* Fixed all elog related warnings, as well as a few others.Peter Eisentraut2000-01-15
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