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* Clean up warnings from -Wimplicit-fallthrough.Tom Lane2018-05-01
| | | | | | | | | | | | | | | | | | | | | | | | | Recent gcc can warn about switch-case fall throughs that are not explicitly labeled as intentional. This seems like a good thing, so clean up the warnings exposed thereby by labeling all such cases with comments that gcc will recognize. In files that already had one or more suitable comments, I generally matched the existing style of those. Otherwise I went with /* FALLTHROUGH */, which is one of the spellings approved at the more-restrictive-than-default level -Wimplicit-fallthrough=4. (At the default level you can also spell it /* FALL ?THRU */, and it's not picky about case. What you can't do is include additional text in the same comment, so some existing comments containing versions of this aren't good enough.) Testing with gcc 8.0.1 (Fedora 28's current version), I found that I also had to put explicit "break"s after elog(ERROR) or ereport(ERROR); apparently, for this purpose gcc doesn't recognize that those don't return. That seems like possibly a gcc bug, but it's fine because in most places we did that anyway; so this amounts to a visit from the style police. Discussion: https://postgr.es/m/15083.1525207729@sss.pgh.pa.us
* Revert MERGE patchSimon Riggs2018-04-12
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This reverts commits d204ef63776b8a00ca220adec23979091564e465, 83454e3c2b28141c0db01c7d2027e01040df5249 and a few more commits thereafter (complete list at the end) related to MERGE feature. While the feature was fully functional, with sufficient test coverage and necessary documentation, it was felt that some parts of the executor and parse-analyzer can use a different design and it wasn't possible to do that in the available time. So it was decided to revert the patch for PG11 and retry again in the future. Thanks again to all reviewers and bug reporters. List of commits reverted, in reverse chronological order: f1464c5380 Improve parse representation for MERGE ddb4158579 MERGE syntax diagram correction 530e69e59b Allow cpluspluscheck to pass by renaming variable 01b88b4df5 MERGE minor errata 3af7b2b0d4 MERGE fix variable warning in non-assert builds a5d86181ec MERGE INSERT allows only one VALUES clause 4b2d44031f MERGE post-commit review 4923550c20 Tab completion for MERGE aa3faa3c7a WITH support in MERGE 83454e3c2b New files for MERGE d204ef6377 MERGE SQL Command following SQL:2016 Author: Pavan Deolasee Reviewed-by: Michael Paquier
* Fix IndexOnlyScan counter for heap fetches in parallel modeAlvaro Herrera2018-04-10
| | | | | | | | | | | | The HeapFetches counter was using a simple value in IndexOnlyScanState, which fails to propagate values from parallel workers; so the counts are wrong when IndexOnlyScan runs in parallel. Move it to Instrumentation, like all the other counters. While at it, change INSERT ON CONFLICT conflicting tuple counter to use the new ntuples2 instead of nfiltered2, which is a blatant misuse. Discussion: https://postgr.es/m/20180409215851.idwc75ct2bzi6tea@alvherre.pgsql
* Support partition pruning at execution timeAlvaro Herrera2018-04-07
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Existing partition pruning is only able to work at plan time, for query quals that appear in the parsed query. This is good but limiting, as there can be parameters that appear later that can be usefully used to further prune partitions. This commit adds support for pruning subnodes of Append which cannot possibly contain any matching tuples, during execution, by evaluating Params to determine the minimum set of subnodes that can possibly match. We support more than just simple Params in WHERE clauses. Support additionally includes: 1. Parameterized Nested Loop Joins: The parameter from the outer side of the join can be used to determine the minimum set of inner side partitions to scan. 2. Initplans: Once an initplan has been executed we can then determine which partitions match the value from the initplan. Partition pruning is performed in two ways. When Params external to the plan are found to match the partition key we attempt to prune away unneeded Append subplans during the initialization of the executor. This allows us to bypass the initialization of non-matching subplans meaning they won't appear in the EXPLAIN or EXPLAIN ANALYZE output. For parameters whose value is only known during the actual execution then the pruning of these subplans must wait. Subplans which are eliminated during this stage of pruning are still visible in the EXPLAIN output. In order to determine if pruning has actually taken place, the EXPLAIN ANALYZE must be viewed. If a certain Append subplan was never executed due to the elimination of the partition then the execution timing area will state "(never executed)". Whereas, if, for example in the case of parameterized nested loops, the number of loops stated in the EXPLAIN ANALYZE output for certain subplans may appear lower than others due to the subplan having been scanned fewer times. This is due to the list of matching subnodes having to be evaluated whenever a parameter which was found to match the partition key changes. This commit required some additional infrastructure that permits the building of a data structure which is able to perform the translation of the matching partition IDs, as returned by get_matching_partitions, into the list index of a subpaths list, as exist in node types such as Append, MergeAppend and ModifyTable. This allows us to translate a list of clauses into a Bitmapset of all the subpath indexes which must be included to satisfy the clause list. Author: David Rowley, based on an earlier effort by Beena Emerson Reviewers: Amit Langote, Robert Haas, Amul Sul, Rajkumar Raghuwanshi, Jesper Pedersen Discussion: https://postgr.es/m/CAOG9ApE16ac-_VVZVvv0gePSgkg_BwYEV1NBqZFqDR2bBE0X0A@mail.gmail.com
* MERGE SQL Command following SQL:2016Simon Riggs2018-04-03
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | MERGE performs actions that modify rows in the target table using a source table or query. MERGE provides a single SQL statement that can conditionally INSERT/UPDATE/DELETE rows a task that would other require multiple PL statements. e.g. MERGE INTO target AS t USING source AS s ON t.tid = s.sid WHEN MATCHED AND t.balance > s.delta THEN UPDATE SET balance = t.balance - s.delta WHEN MATCHED THEN DELETE WHEN NOT MATCHED AND s.delta > 0 THEN INSERT VALUES (s.sid, s.delta) WHEN NOT MATCHED THEN DO NOTHING; MERGE works with regular and partitioned tables, including column and row security enforcement, as well as support for row, statement and transition triggers. MERGE is optimized for OLTP and is parameterizable, though also useful for large scale ETL/ELT. MERGE is not intended to be used in preference to existing single SQL commands for INSERT, UPDATE or DELETE since there is some overhead. MERGE can be used statically from PL/pgSQL. MERGE does not yet support inheritance, write rules, RETURNING clauses, updatable views or foreign tables. MERGE follows SQL Standard per the most recent SQL:2016. Includes full tests and documentation, including full isolation tests to demonstrate the concurrent behavior. This version written from scratch in 2017 by Simon Riggs, using docs and tests originally written in 2009. Later work from Pavan Deolasee has been both complex and deep, leaving the lead author credit now in his hands. Extensive discussion of concurrency from Peter Geoghegan, with thanks for the time and effort contributed. Various issues reported via sqlsmith by Andreas Seltenreich Authors: Pavan Deolasee, Simon Riggs Reviewer: Peter Geoghegan, Amit Langote, Tomas Vondra, Simon Riggs Discussion: https://postgr.es/m/CANP8+jKitBSrB7oTgT9CY2i1ObfOt36z0XMraQc+Xrz8QB0nXA@mail.gmail.com https://postgr.es/m/CAH2-WzkJdBuxj9PO=2QaO9-3h3xGbQPZ34kJH=HukRekwM-GZg@mail.gmail.com
* Revert "Modified files for MERGE"Simon Riggs2018-04-02
| | | | This reverts commit 354f13855e6381d288dfaa52bcd4f2cb0fd4a5eb.
* Modified files for MERGESimon Riggs2018-04-02
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* Add EXPLAIN support for JIT.Andres Freund2018-03-28
| | | | | | | | | | This just shows a few details about JITing, e.g. how many functions have been JITed, and how long that took. To avoid noise in regression tests with functions sometimes being JITed in --with-llvm builds, disable display when COSTS OFF is specified. Author: Andres Freund Discussion: https://postgr.es/m/20170901064131.tazjxwus3k2w3ybh@alap3.anarazel.de
* Add 'unit' parameter to ExplainProperty{Integer,Float}.Andres Freund2018-03-16
| | | | | | | | | | | This allows to deduplicate some existing code, but mainly avoids some duplication in upcoming commits. In passing, fix variable names indicating wrong unit (seconds instead of ms). Author: Andres Freund Discussion: https://postgr.es/m/20180314002740.cah3mdsonz5mxney@alap3.anarazel.de
* Make ExplainPropertyInteger accept 64bit input, remove *Long variant.Andres Freund2018-03-16
| | | | | | | | | | | | 'long' is not useful type across platforms, as it's 32bit on 32 bit platforms, and even on some 64bit platforms (e.g. windows) it's still only 32bits wide. As ExplainPropertyInteger should never be performance critical, change it to accept a 64bit argument and remove ExplainPropertyLong. Author: Andres Freund Discussion: https://postgr.es/m/20180314164832.n56wt7zcbpzi6zxe@alap3.anarazel.de
* Fix more format truncation issuesPeter Eisentraut2018-03-15
| | | | | | | | | | | | | | | | | | | | | | Fix the warnings created by the compiler warning options -Wformat-overflow=2 -Wformat-truncation=2, supported since GCC 7. This is a more aggressive variant of the fixes in 6275f5d28a1577563f53f2171689d4f890a46881, which GCC 7 warned about by default. The issues are all harmless, but some dubious coding patterns are cleaned up. One issue that is of external interest is that BGW_MAXLEN is increased from 64 to 96. Apparently, the old value would cause the bgw_name of logical replication workers to be truncated in some circumstances. But this doesn't actually add those warning options. It appears that the warnings depend a bit on compilation and optimization options, so it would be annoying to have to keep up with that. This is more of a once-in-a-while cleanup. Reviewed-by: Michael Paquier <michael@paquier.xyz>
* Avoid listing the same ResultRelInfo in more than one EState list.Robert Haas2018-02-08
| | | | | | | | Doing so causes EXPLAIN ANALYZE to show trigger statistics multiple times. Commit 2f178441044be430f6b4d626e4dae68a9a6f6cec seems to be to blame for this. Amit Langote, revieed by Amit Khandekar, Etsuro Fujita, and me.
* Add QueryEnvironment to ExplainOneQuery_hook's parameter list.Tom Lane2018-01-11
| | | | | | | | | | | | | | This should have been done in commit 18ce3a4ab, which added that parameter to ExplainOneQuery, but it was overlooked. This makes it impossible for a user of the hook to pass the queryEnv down to ExplainOnePlan. It's too late to change this API in v10, I suppose, but fortunately passing NULL to ExplainOnePlan will work in nearly all interesting cases in v10. That might not be true forever, so we'd better fix it. Tatsuro Yamada, reviewed by Thomas Munro Discussion: https://postgr.es/m/890e8dd9-c1c7-a422-6892-874f5eaee048@lab.ntt.co.jp
* Update copyright for 2018Bruce Momjian2018-01-02
| | | | Backpatch-through: certain files through 9.3
* Fix EXPLAIN ANALYZE output for Parallel Hash.Andres Freund2018-01-01
| | | | | | | | | | | | | | In a race case, EXPLAIN ANALYZE could fail to display correct nbatch and size information. Refactor so that participants report only on batches they worked on rather than trying to report on all of them, and teach explain.c to consider the HashInstrumentation object from all participants instead of picking the first one it can find. This should fix an occasional build farm failure in the "join" regression test. Author: Thomas Munro Reviewed-By: Andres Freund Discussion: https://postgr.es/m/30219.1514428346%40sss.pgh.pa.us
* Fix EXPLAIN ANALYZE of hash join when the leader doesn't participate.Andres Freund2017-12-05
| | | | | | | | | | | | | | | | | | | | If a hash join appears in a parallel query, there may be no hash table available for explain.c to inspect even though a hash table may have been built in other processes. This could happen either because parallel_leader_participation was set to off or because the leader happened to hit the end of the outer relation immediately (even though the complete relation is not empty) and decided not to build the hash table. Commit bf11e7ee introduced a way for workers to exchange instrumentation via the DSM segment for Sort nodes even though they are not parallel-aware. This commit does the same for Hash nodes, so that explain.c has a way to find instrumentation data from an arbitrary participant that actually built the hash table. Author: Thomas Munro Reviewed-By: Andres Freund Discussion: https://postgr.es/m/CAEepm%3D3DUQC2-z252N55eOcZBer6DPdM%3DFzrxH9dZc5vYLsjaA%40mail.gmail.com
* Pass InitPlan values to workers via Gather (Merge).Robert Haas2017-11-16
| | | | | | | | | | | | | | | | | | | | | | | | | | If a PARAM_EXEC parameter is used below a Gather (Merge) but the InitPlan that computes it is attached to or above the Gather (Merge), force the value to be computed before starting parallelism and pass it down to all workers. This allows us to use parallelism in cases where it previously would have had to be rejected as unsafe. We do - in this case - lose the optimization that the value is only computed if it's actually used. An alternative strategy would be to have the first worker that needs the value compute it, but one downside of that approach is that we'd then need to select a parallel-safe path to compute the parameter value; it couldn't for example contain a Gather (Merge) node. At some point in the future, we might want to consider both approaches. Independent of that consideration, there is a great deal more work that could be done to make more kinds of PARAM_EXEC parameters parallel-safe. This infrastructure could be used to allow a Gather (Merge) on the inner side of a nested loop (although that's not a very appealing plan) and cases where the InitPlan is attached below the Gather (Merge) could be addressed as well using various techniques. But this is a good start. Amit Kapila, reviewed and revised by me. Reviewing and testing from Kuntal Ghosh, Haribabu Kommi, and Tushar Ahuja. Discussion: http://postgr.es/m/CAA4eK1LV0Y1AUV4cUCdC+sYOx0Z0-8NAJ2Pd9=UKsbQ5Sr7+JQ@mail.gmail.com
* Allow DML commands that create tables to use parallel query.Robert Haas2017-10-05
| | | | | | | | | | | Haribabu Kommi, reviewed by Dilip Kumar and Rafia Sabih. Various cosmetic changes by me to explain why this appears to be safe but allowing inserts in parallel mode in general wouldn't be. Also, I removed the REFRESH MATERIALIZED VIEW case from Haribabu's patch, since I'm not convinced that case is OK, and hacked on the documentation somewhat. Discussion: http://postgr.es/m/CAJrrPGdo5bak6qnPWe8Kpi8g_jfQEs-G4SYmG9y+OFaw2-dPvA@mail.gmail.com
* Make ExplainOpenGroup and ExplainCloseGroup public.Tom Lane2017-09-18
| | | | | | | | | Extensions with custom plan nodes might like to use these in their EXPLAIN output. Hadi Moshayedi Discussion: https://postgr.es/m/CA+_kT_dU-rHCN0u6pjA6bN5CZniMfD=-wVqPY4QLrKUY_uJq5w@mail.gmail.com
* Propagate sort instrumentation from workers back to leader.Robert Haas2017-08-29
| | | | | | | | | | | | | | | | Up until now, when parallel query was used, no details about the sort method or space used by the workers were available; details were shown only for any sorting done by the leader. Fix that. Commit 1177ab1dabf72bafee8f19d904cee3a299f25892 forced the test case added by commit 1f6d515a67ec98194c23a5db25660856c9aab944 to run without parallelism; now that we have this infrastructure, allow that again, with a little tweaking to make it pass with and without force_parallel_mode. Robert Haas and Tom Lane Discussion: http://postgr.es/m/CA+Tgmoa2VBZW6S8AAXfhpHczb=Rf6RqQ2br+zJvEgwJ0uoD_tQ@mail.gmail.com
* Fix interaction of triggers, partitioning, and EXPLAIN ANALYZE.Robert Haas2017-08-18
| | | | | | | | | | | Add a new EState member es_leaf_result_relations, so that the trigger code knows about ResultRelInfos created by tuple routing. Also make sure ExplainPrintTriggers knows about partition-related ResultRelInfos. Etsuro Fujita, reviewed by Amit Langote Discussion: http://postgr.es/m/57163e18-8e56-da83-337a-22f2c0008051@lab.ntt.co.jp
* Phase 3 of pgindent updates.Tom Lane2017-06-21
| | | | | | | | | | | | | | | | | | | | | | | | | Don't move parenthesized lines to the left, even if that means they flow past the right margin. By default, BSD indent lines up statement continuation lines that are within parentheses so that they start just to the right of the preceding left parenthesis. However, traditionally, if that resulted in the continuation line extending to the right of the desired right margin, then indent would push it left just far enough to not overrun the margin, if it could do so without making the continuation line start to the left of the current statement indent. That makes for a weird mix of indentations unless one has been completely rigid about never violating the 80-column limit. This behavior has been pretty universally panned by Postgres developers. Hence, disable it with indent's new -lpl switch, so that parenthesized lines are always lined up with the preceding left paren. 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
* Improve castNode notation by introducing list-extraction-specific variants.Tom Lane2017-04-10
| | | | | | | | | | | | | | | | | This extends the castNode() notation introduced by commit 5bcab1114 to provide, in one step, extraction of a list cell's pointer and coercion to a concrete node type. For example, "lfirst_node(Foo, lc)" is the same as "castNode(Foo, lfirst(lc))". Almost half of the uses of castNode that have appeared so far include a list extraction call, so this is pretty widely useful, and it saves a few more keystrokes compared to the old way. As with the previous patch, back-patch the addition of these macros to pg_list.h, so that the notation will be available when back-patching. Patch by me, after an idea of Andrew Gierth's. Discussion: https://postgr.es/m/14197.1491841216@sss.pgh.pa.us
* Optimize joins when the inner relation can be proven unique.Tom Lane2017-04-07
| | | | | | | | | | | | | | | | | | | | | | | If there can certainly be no more than one matching inner row for a given outer row, then the executor can move on to the next outer row as soon as it's found one match; there's no need to continue scanning the inner relation for this outer row. This saves useless scanning in nestloop and hash joins. In merge joins, it offers the opportunity to skip mark/restore processing, because we know we have not advanced past the first possible match for the next outer row. Of course, the devil is in the details: the proof of uniqueness must depend only on joinquals (not otherquals), and if we want to skip mergejoin mark/restore then it must depend only on merge clauses. To avoid adding more planning overhead than absolutely necessary, the present patch errs in the conservative direction: there are cases where inner_unique or skip_mark_restore processing could be used, but it will not do so because it's not sure that the uniqueness proof depended only on "safe" clauses. This could be improved later. David Rowley, reviewed and rather heavily editorialized on by me Discussion: https://postgr.es/m/CAApHDvqF6Sw-TK98bW48TdtFJ+3a7D2mFyZ7++=D-RyPsL76gw@mail.gmail.com
* Add infrastructure to support EphemeralNamedRelation references.Kevin Grittner2017-03-31
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | A QueryEnvironment concept is added, which allows new types of objects to be passed into queries from parsing on through execution. At this point, the only thing implemented is a collection of EphemeralNamedRelation objects -- relations which can be referenced by name in queries, but do not exist in the catalogs. The only type of ENR implemented is NamedTuplestore, but provision is made to add more types fairly easily. An ENR can carry its own TupleDesc or reference a relation in the catalogs by relid. Although these features can be used without SPI, convenience functions are added to SPI so that ENRs can easily be used by code run through SPI. The initial use of all this is going to be transition tables in AFTER triggers, but that will be added to each PL as a separate commit. An incidental effect of this patch is to produce a more informative error message if an attempt is made to modify the contents of a CTE from a referencing DML statement. No tests previously covered that possibility, so one is added. Kevin Grittner and Thomas Munro Reviewed by Heikki Linnakangas, David Fetter, and Thomas Munro with valuable comments and suggestions from many others
* Support hashed aggregation with grouping sets.Andrew Gierth2017-03-27
| | | | | | | | | | | | | | | | | | This extends the Aggregate node with two new features: HashAggregate can now run multiple hashtables concurrently, and a new strategy MixedAggregate populates hashtables while doing sorted grouping. The planner will now attempt to save as many sorts as possible when planning grouping sets queries, while not exceeding work_mem for the estimated combined sizes of all hashtables used. No SQL-level changes are required. There should be no user-visible impact other than the new EXPLAIN output and possible changes to result ordering when ORDER BY was not used (which affected a few regression tests). The enable_hashagg option is respected. Author: Andrew Gierth Reviewers: Mark Dilger, Andres Freund Discussion: https://postgr.es/m/87vatszyhj.fsf@news-spur.riddles.org.uk
* Faster expression evaluation and targetlist projection.Andres Freund2017-03-25
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This replaces the old, recursive tree-walk based evaluation, with non-recursive, opcode dispatch based, expression evaluation. Projection is now implemented as part of expression evaluation. This both leads to significant performance improvements, and makes future just-in-time compilation of expressions easier. The speed gains primarily come from: - non-recursive implementation reduces stack usage / overhead - simple sub-expressions are implemented with a single jump, without function calls - sharing some state between different sub-expressions - reduced amount of indirect/hard to predict memory accesses by laying out operation metadata sequentially; including the avoidance of nearly all of the previously used linked lists - more code has been moved to expression initialization, avoiding constant re-checks at evaluation time Future just-in-time compilation (JIT) has become easier, as demonstrated by released patches intended to be merged in a later release, for primarily two reasons: Firstly, due to a stricter split between expression initialization and evaluation, less code has to be handled by the JIT. Secondly, due to the non-recursive nature of the generated "instructions", less performance-critical code-paths can easily be shared between interpreted and compiled evaluation. The new framework allows for significant future optimizations. E.g.: - basic infrastructure for to later reduce the per executor-startup overhead of expression evaluation, by caching state in prepared statements. That'd be helpful in OLTPish scenarios where initialization overhead is measurable. - optimizing the generated "code". A number of proposals for potential work has already been made. - optimizing the interpreter. Similarly a number of proposals have been made here too. The move of logic into the expression initialization step leads to some backward-incompatible changes: - Function permission checks are now done during expression initialization, whereas previously they were done during execution. In edge cases this can lead to errors being raised that previously wouldn't have been, e.g. a NULL array being coerced to a different array type previously didn't perform checks. - The set of domain constraints to be checked, is now evaluated once during expression initialization, previously it was re-built every time a domain check was evaluated. For normal queries this doesn't change much, but e.g. for plpgsql functions, which caches ExprStates, the old set could stick around longer. The behavior around might still change. Author: Andres Freund, with significant changes by Tom Lane, changes by Heikki Linnakangas Reviewed-By: Tom Lane, Heikki Linnakangas Discussion: https://postgr.es/m/20161206034955.bh33paeralxbtluv@alap3.anarazel.de
* Allow for parallel execution whenever ExecutorRun() is done only once.Robert Haas2017-03-23
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Previously, it was unsafe to execute a plan in parallel if ExecutorRun() might be called with a non-zero row count. However, it's quite easy to fix things up so that we can support that case, provided that it is known that we will never call ExecutorRun() a second time for the same QueryDesc. Add infrastructure to signal this, and cross-checks to make sure that a caller who claims this is true doesn't later reneg. While that pattern never happens with queries received directly from a client -- there's no way to know whether multiple Execute messages will be sent unless the first one requests all the rows -- it's pretty common for queries originating from procedural languages, which often limit the result to a single tuple or to a user-specified number of tuples. This commit doesn't actually enable parallelism in any additional cases, because currently none of the places that would be able to benefit from this infrastructure pass CURSOR_OPT_PARALLEL_OK in the first place, but it makes it much more palatable to pass CURSOR_OPT_PARALLEL_OK in places where we currently don't, because it eliminates some cases where we'd end up having to run the parallel plan serially. Patch by me, based on some ideas from Rafia Sabih and corrected by Rafia Sabih based on feedback from Dilip Kumar and myself. Discussion: http://postgr.es/m/CA+TgmobXEhvHbJtWDuPZM9bVSLiTj-kShxQJ2uM5GPDze9fRYA@mail.gmail.com
* Add a Gather Merge executor node.Robert Haas2017-03-09
| | | | | | | | | | | | | | | | | | | | Like Gather, we spawn multiple workers and run the same plan in each one; however, Gather Merge is used when each worker produces the same output ordering and we want to preserve that output ordering while merging together the streams of tuples from various workers. (In a way, Gather Merge is like a hybrid of Gather and MergeAppend.) This works out to a win if it saves us from having to perform an expensive Sort. In cases where only a small amount of data would need to be sorted, it may actually be faster to use a regular Gather node and then sort the results afterward, because Gather Merge sometimes needs to wait synchronously for tuples whereas a pure Gather generally doesn't. But if this avoids an expensive sort then it's a win. Rushabh Lathia, reviewed and tested by Amit Kapila, Thomas Munro, and Neha Sharma, and reviewed and revised by me. Discussion: http://postgr.es/m/CAGPqQf09oPX-cQRpBKS0Gq49Z+m6KBxgxd_p9gX8CKk_d75HoQ@mail.gmail.com
* Expose explain's SUMMARY optionStephen Frost2017-03-08
| | | | | | | | | | | | | | | | | | | | | | | | | This exposes the existing explain summary option to users to allow them to choose if they wish to have the planning time and totalled run time included in the EXPLAIN result. The existing default behavior is retained if SUMMARY is not specified- running explain without analyze will not print the summary lines (just the planning time, currently) while running explain with analyze will include the summary lines (both the planning time and the totalled execution time). Users who wish to see the summary information for plain explain can now use: EXPLAIN (SUMMARY ON) query; Users who do not want to have the summary printed for an analyze run can use: EXPLAIN (ANALYZE ON, SUMMARY OFF) query; With this, we can now also have EXPLAIN ANALYZE queries included in our regression tests by using: EXPLAIN (ANALYZE ON, TIMING OFF, SUMMARY off) query; I went ahead and added an example of this, which will hopefully not make the buildfarm complain. Author: Ashutosh Bapat Discussion: https://postgr.es/m/CAFjFpReE5z2h98U2Vuia8hcEkpRRwrauRjHmyE44hNv8-xk+XA@mail.gmail.com
* Support XMLTABLE query expressionAlvaro Herrera2017-03-08
| | | | | | | | | | | | | | | | | | | | | | | | | | | | XMLTABLE is defined by the SQL/XML standard as a feature that allows turning XML-formatted data into relational form, so that it can be used as a <table primary> in the FROM clause of a query. This new construct provides significant simplicity and performance benefit for XML data processing; what in a client-side custom implementation was reported to take 20 minutes can be executed in 400ms using XMLTABLE. (The same functionality was said to take 10 seconds using nested PostgreSQL XPath function calls, and 5 seconds using XMLReader under PL/Python). The implemented syntax deviates slightly from what the standard requires. First, the standard indicates that the PASSING clause is optional and that multiple XML input documents may be given to it; we make it mandatory and accept a single document only. Second, we don't currently support a default namespace to be specified. This implementation relies on a new executor node based on a hardcoded method table. (Because the grammar is fixed, there is no extensibility in the current approach; further constructs can be implemented on top of this such as JSON_TABLE, but they require changes to core code.) Author: Pavel Stehule, Álvaro Herrera Extensively reviewed by: Craig Ringer Discussion: https://postgr.es/m/CAFj8pRAgfzMD-LoSmnMGybD0WsEznLHWap8DO79+-GTRAPR4qA@mail.gmail.com
* Fix typos in comments.Heikki Linnakangas2017-02-06
| | | | | | | | | Backpatch to all supported versions, where applicable, to make backpatching of future fixes go more smoothly. Josh Soref Discussion: https://www.postgresql.org/message-id/CACZqfqCf+5qRztLPgmmosr-B0Ye4srWzzw_mo4c_8_B_mtjmJQ@mail.gmail.com
* Use castNode() in a bunch of statement-list-related code.Tom Lane2017-01-26
| | | | | | | | | | | | | When I wrote commit ab1f0c822, I really missed the castNode() macro that Peter E. had proposed shortly before. This back-fills the uses I would have put it to. It's probably not all that significant, but there are more assertions here than there were before, and conceivably they will help catch any bugs associated with those representation changes. I left behind a number of usages like "(Query *) copyObject(query_var)". Those could have been converted as well, but Peter has proposed another notational improvement that would handle copyObject cases automatically, so I let that be for now.
* Use the new castNode() macro in a number of places.Andres Freund2017-01-26
| | | | | | | | | This is far from a pervasive conversion, but it's a good starting point. Author: Peter Eisentraut, with some minor changes by me Reviewed-By: Tom Lane Discussion: https://postgr.es/m/c5d387d9-3440-f5e0-f9d4-71d53b9fbe52@2ndquadrant.com
* Move targetlist SRF handling from expression evaluation to new executor node.Andres Freund2017-01-18
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Evaluation of set returning functions (SRFs_ in the targetlist (like SELECT generate_series(1,5)) so far was done in the expression evaluation (i.e. ExecEvalExpr()) and projection (i.e. ExecProject/ExecTargetList) code. This meant that most executor nodes performing projection, and most expression evaluation functions, had to deal with the possibility that an evaluated expression could return a set of return values. That's bad because it leads to repeated code in a lot of places. It also, and that's my (Andres's) motivation, made it a lot harder to implement a more efficient way of doing expression evaluation. To fix this, introduce a new executor node (ProjectSet) that can evaluate targetlists containing one or more SRFs. To avoid the complexity of the old way of handling nested expressions returning sets (e.g. having to pass up ExprDoneCond, and dealing with arguments to functions returning sets etc.), those SRFs can only be at the top level of the node's targetlist. The planner makes sure (via split_pathtarget_at_srfs()) that SRF evaluation is only necessary in ProjectSet nodes and that SRFs are only present at the top level of the node's targetlist. If there are nested SRFs the planner creates multiple stacked ProjectSet nodes. The ProjectSet nodes always get input from an underlying node. We also discussed and prototyped evaluating targetlist SRFs using ROWS FROM(), but that turned out to be more complicated than we'd hoped. While moving SRF evaluation to ProjectSet would allow to retain the old "least common multiple" behavior when multiple SRFs are present in one targetlist (i.e. continue returning rows until all SRFs are at the end of their input at the same time), we decided to instead only return rows till all SRFs are exhausted, returning NULL for already exhausted ones. We deemed the previous behavior to be too confusing, unexpected and actually not particularly useful. As a side effect, the previously prohibited case of multiple set returning arguments to a function, is now allowed. Not because it's particularly desirable, but because it ends up working and there seems to be no argument for adding code to prohibit it. Currently the behavior for COALESCE and CASE containing SRFs has changed, returning multiple rows from the expression, even when the SRF containing "arm" of the expression is not evaluated. That's because the SRFs are evaluated in a separate ProjectSet node. As that's quite confusing, we're likely to instead prohibit SRFs in those places. But that's still being discussed, and the code would reside in places not touched here, so that's a task for later. There's a lot of, now superfluous, code dealing with set return expressions around. But as the changes to get rid of those are verbose largely boring, it seems better for readability to keep the cleanup as a separate commit. Author: Tom Lane and Andres Freund Discussion: https://postgr.es/m/20160822214023.aaxz5l4igypowyri@alap3.anarazel.de
* Change representation of statement lists, and add statement location info.Tom Lane2017-01-14
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch makes several changes that improve the consistency of representation of lists of statements. It's always been the case that the output of parse analysis is a list of Query nodes, whatever the types of the individual statements in the list. This patch brings similar consistency to the outputs of raw parsing and planning steps: * The output of raw parsing is now always a list of RawStmt nodes; the statement-type-dependent nodes are one level down from that. * The output of pg_plan_queries() is now always a list of PlannedStmt nodes, even for utility statements. In the case of a utility statement, "planning" just consists of wrapping a CMD_UTILITY PlannedStmt around the utility node. This list representation is now used in Portal and CachedPlan plan lists, replacing the former convention of intermixing PlannedStmts with bare utility-statement nodes. Now, every list of statements has a consistent head-node type depending on how far along it is in processing. This allows changing many places that formerly used generic "Node *" pointers to use a more specific pointer type, thus reducing the number of IsA() tests and casts needed, as well as improving code clarity. Also, the post-parse-analysis representation of DECLARE CURSOR is changed so that it looks more like EXPLAIN, PREPARE, etc. That is, the contained SELECT remains a child of the DeclareCursorStmt rather than getting flipped around to be the other way. It's now true for both Query and PlannedStmt that utilityStmt is non-null if and only if commandType is CMD_UTILITY. That allows simplifying a lot of places that were testing both fields. (I think some of those were just defensive programming, but in many places, it was actually necessary to avoid confusing DECLARE CURSOR with SELECT.) Because PlannedStmt carries a canSetTag field, we're also able to get rid of some ad-hoc rules about how to reconstruct canSetTag for a bare utility statement; specifically, the assumption that a utility is canSetTag if and only if it's the only one in its list. While I see no near-term need for relaxing that restriction, it's nice to get rid of the ad-hocery. The API of ProcessUtility() is changed so that what it's passed is the wrapper PlannedStmt not just the bare utility statement. This will affect all users of ProcessUtility_hook, but the changes are pretty trivial; see the affected contrib modules for examples of the minimum change needed. (Most compilers should give pointer-type-mismatch warnings for uncorrected code.) There's also a change in the API of ExplainOneQuery_hook, to pass through cursorOptions instead of expecting hook functions to know what to pick. This is needed because of the DECLARE CURSOR changes, but really should have been done in 9.6; it's unlikely that any extant hook functions know about using CURSOR_OPT_PARALLEL_OK. Finally, teach gram.y to save statement boundary locations in RawStmt nodes, and pass those through to Query and PlannedStmt nodes. This allows more intelligent handling of cases where a source query string contains multiple statements. This patch doesn't actually do anything with the information, but a follow-on patch will. (Passing this information through cleanly is the true motivation for these changes; while I think this is all good cleanup, it's unlikely we'd have bothered without this end goal.) catversion bump because addition of location fields to struct Query affects stored rules. This patch is by me, but it owes a good deal to Fabien Coelho who did a lot of preliminary work on the problem, and also reviewed the patch. Discussion: https://postgr.es/m/alpine.DEB.2.20.1612200926310.29821@lancre
* Update copyright via script for 2017Bruce Momjian2017-01-03
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* Fix EXPLAIN so that it doesn't emit invalid XML in corner cases.Tom Lane2016-10-20
| | | | | | | | | | | | | | | | | | | | With track_io_timing = on, EXPLAIN (ANALYZE, BUFFERS) will emit fields named like "I/O Read Time". The slash makes that invalid as an XML element name, so that adding FORMAT XML would produce invalid XML. We already have code in there to translate spaces to dashes, so let's generalize that to convert anything that isn't a valid XML name character, viz letters, digits, hyphens, underscores, and periods. We could just reject slashes, which would run a bit faster. But the fact that this went unnoticed for so long doesn't give me a warm feeling that we'd notice the next creative violation, so let's make it a permanent fix. Reported by Markus Winand, though this isn't his initial patch proposal. Back-patch to 9.2 where track_io_timing was added. The problem is only latent in 9.1, so I don't feel a need to fix it there. Discussion: <E0BF6A45-68E8-45E6-918F-741FB332C6BB@winand.at>
* Add location field to DefElemPeter Eisentraut2016-09-06
| | | | | | | | | | | | | | Add a location field to the DefElem struct, used to parse many utility commands. Update various error messages to supply error position information. To propogate the error position information in a more systematic way, create a ParseState in standard_ProcessUtility() and pass that to interested functions implementing the utility commands. This seems better than passing the query string and then reassembling a parse state ad hoc, which violates the encapsulation of the ParseState type. Reviewed-by: Pavel Stehule <pavel.stehule@gmail.com>
* Fix inappropriate printing of never-measured times in EXPLAIN.Tom Lane2016-08-12
| | | | | | | | | | | | | | | | | EXPLAIN (ANALYZE, TIMING OFF) would print an elapsed time of zero for a trigger function, because no measurement has been taken but it printed the field anyway. This isn't what EXPLAIN does elsewhere, so suppress it. In the same vein, EXPLAIN (ANALYZE, BUFFERS) with non-text output format would print buffer I/O timing numbers even when no measurement has been taken because track_io_timing is off. That seems not per policy, either, so change it. Back-patch to 9.2 where these features were introduced. Maksim Milyutin Discussion: <081c0540-ecaa-bd29-3fd2-6358f3b359a9@postgrespro.ru>
* Print a given subplan only once in EXPLAIN.Tom Lane2016-07-11
| | | | | | | | | | | | | | | | | | | | | | | | | | | | We have, for a very long time, allowed the same subplan (same member of the PlannedStmt.subplans list) to be referenced by more than one SubPlan node; this avoids problems for cases such as subplans within an IndexScan's indxqual and indxqualorig fields. However, EXPLAIN had not gotten the memo and would print each reference as though it were an independent identical subplan. To fix, track plan_ids of subplans we've printed and don't print the same plan_id twice. Per report from Pavel Stehule. BTW: the particular case of IndexScan didn't cause visible duplication in a plain EXPLAIN, only EXPLAIN ANALYZE, because in the former case we short-circuit executor startup before the indxqual field is processed by ExecInitExpr. That seems like it could easily lead to other EXPLAIN problems in future, but it's not clear how to avoid it without breaking the "EXPLAIN a plan using hypothetical indexes" use-case. For now I've left that issue alone. Although this is a longstanding bug, it's purely cosmetic (no great harm is done by the repeat printout) and we haven't had field complaints before. So I'm hesitant to back-patch it, especially since there is some small risk of ABI problems due to the need to add a new field to ExplainState. In passing, rearrange order of fields in ExplainState to be less random, and update some obsolete comments about when/where to initialize them. Report: <CAFj8pRAimq+NK-menjt+3J4-LFoodDD8Or6=Lc_stcFD+eD4DA@mail.gmail.com>
* Fix some infelicities in EXPLAIN output for parallel query plans.Tom Lane2016-06-29
| | | | | | | | | | | | | | | | | | | | | | | | | | In non-text output formats, parallelized aggregates were reporting "Partial" or "Finalize" as a field named "Operation", which might be all right in the absence of any context --- but other plan node types use that field to report SQL-visible semantics, such as Select/Insert/Update/Delete. So that naming choice didn't seem good to me. I changed it to "Partial Mode". Also, the field did not appear at all for a non-parallelized Agg plan node, which is contrary to expectation in non-text formats. We're notionally producing objects that conform to a schema, so the set of fields for a given node type and EXPLAIN mode should be well-defined. I set it up to fill in "Simple" in such cases. Other fields that were added for parallel query, namely "Parallel Aware" and Gather's "Single Copy", had not gotten the word on that point either. Make them appear always in non-text output. Also, the latter two fields were nominally producing boolean output, but were getting it wrong, because bool values shouldn't be quoted in JSON or YAML. Somehow we'd not needed an ExplainPropertyBool formatting subroutine before 9.6; but now we do, so invent it. Discussion: <16002.1466972724@sss.pgh.pa.us>
* Rethink node-level representation of partial-aggregation modes.Tom Lane2016-06-26
| | | | | | | | | | | | | | | | | | | | | | | | | | | The original coding had three separate booleans representing partial aggregation behavior, which was confusing, unreadable, and error-prone, not least because the booleans weren't always listed in the same order. It was also inadequate for the allegedly-desirable future extension to support intermediate partial aggregation, because we'd need separate markers for serialization and deserialization in such a case. Merge these bools into an enum "AggSplit" to provide symbolic names for the supported operating modes (and document what those are). By assigning the values of the enum constants carefully, we can treat AggSplit values as options bitmasks so that tests of what to do aren't noticeably more expensive than before. While at it, get rid of Aggref.aggoutputtype. That's not needed since commit 59a3795c2 got rid of setrefs.c's special-purpose Aggref comparison code, and it likewise seemed more confusing than helpful. Assorted comment cleanup as well (there's still more that I want to do in that line). catversion bump for change in Aggref node contents. Should be the last one for partial-aggregation changes. Discussion: <29309.1466699160@sss.pgh.pa.us>
* Tweak EXPLAIN for parallel query to show workers launched.Robert Haas2016-04-15
| | | | | | | | | The previous display was sort of confusing, because it didn't distinguish between the number of workers that we planned to launch and the number that actually got launched. This has already confused several people, so display both numbers and label them clearly. Julien Rouhaud, reviewed by me.
* Run pgindent on a batch of (mostly-planner-related) source files.Tom Lane2016-04-06
| | | | | Getting annoyed at the amount of unrelated chatter I get from pgindent'ing Rowley's unique-joins patch. Re-indent all the files it touches.
* Rework custom scans to work more like the new extensible node stuff.Robert Haas2016-03-29
| | | | | | | | | | | | | Per discussion, the new extensible node framework is thought to be better designed than the custom path/scan/scanstate stuff we added in PostgreSQL 9.5. Rework the latter to be more like the former. This is not backward-compatible, but we generally don't promise that for C APIs, and there probably aren't many people using this yet anyway. KaiGai Kohei, reviewed by Petr Jelinek and me. Some further cosmetic changes by me.
* Directly modify foreign tables.Robert Haas2016-03-18
| | | | | | | | | postgres_fdw can now sent an UPDATE or DELETE statement directly to the foreign server in simple cases, rather than sending a SELECT FOR UPDATE statement and then updating or deleting rows one-by-one. Etsuro Fujita, reviewed by Rushabh Lathia, Shigeru Hanada, Kyotaro Horiguchi, Albe Laurenz, Thom Brown, and me.
* Fix EXPLAIN ANALYZE SELECT INTO not to choose a parallel plan.Robert Haas2016-03-14
| | | | | | | | | We don't support any parallel write operations at present, so choosing a parallel plan causes us to error out. Also, add a new regression test that uses EXPLAIN ANALYZE SELECT INTO; if we'd had this previously, force_parallel_mode testing would have caught this issue. Mithun Cy and Robert Haas
* Introduce a new GUC force_parallel_mode for testing purposes.Robert Haas2016-02-07
| | | | | | | | | | | | | | | When force_parallel_mode = true, we enable the parallel mode restrictions for all queries for which this is believed to be safe. For the subset of those queries believed to be safe to run entirely within a worker, we spin up a worker and run the query there instead of running it in the original process. When force_parallel_mode = regress, make additional changes to allow the regression tests to run cleanly even though parallel workers have been injected under the hood. Taken together, this facilitates both better user testing and better regression testing of the parallelism code. Robert Haas, with help from Amit Kapila and Rushabh Lathia.
* Support multi-stage aggregation.Robert Haas2016-01-20
| | | | | | | | | | | | | | | | | | | Aggregate nodes now have two new modes: a "partial" mode where they output the unfinalized transition state, and a "finalize" mode where they accept unfinalized transition states rather than individual values as input. These new modes are not used anywhere yet, but they will be necessary for parallel aggregation. The infrastructure also figures to be useful for cases where we want to aggregate local data and remote data via the FDW interface, and want to bring back partial aggregates from the remote side that can then be combined with locally generated partial aggregates to produce the final value. It may also be useful even when neither FDWs nor parallelism are in play, as explained in the comments in nodeAgg.c. David Rowley and Simon Riggs, reviewed by KaiGai Kohei, Heikki Linnakangas, Haribabu Kommi, and me.
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