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2017-04-08Optimize joins when the inner relation can be proven unique.Tom Lane
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
2017-04-07Ensure that ExecPrepareExprList's result is all in one memory context.Tom Lane
Noted by Amit Langote. Discussion: https://postgr.es/m/[email protected]
2017-04-07Clean up after insufficiently-researched optimization of tuple conversions.Tom Lane
tupconvert.c's functions formerly considered that an explicit tuple conversion was necessary if the input and output tupdescs contained different type OIDs. The point of that was to make sure that a composite datum resulting from the conversion would contain the destination rowtype OID in its composite-datum header. However, commit 3838074f8 entirely misunderstood what that check was for, thinking that it had something to do with presence or absence of an OID column within the tuple. Removal of the check broke the no-op conversion path in ExecEvalConvertRowtype, as reported by Ashutosh Bapat. It turns out that of the dozen or so call sites for tupconvert.c functions, ExecEvalConvertRowtype is the only one that cares about the composite-datum header fields in the output tuple. In all the rest, we'd much rather avoid an unnecessary conversion whenever the tuples are physically compatible. Moreover, the comments in tupconvert.c only promise physical compatibility not a metadata match. So, let's accept the removal of the guarantee about the output tuple's rowtype marking, recognizing that this is a API change that could conceivably break third-party callers of tupconvert.c. (So, let's remember to mention it in the v10 release notes.) However, commit 3838074f8 did have a bit of a point here, in that two tuples mustn't be considered physically compatible if one has HEAP_HASOID set and the other doesn't. (Some of the callers of tupconvert.c might not really care about that, but we can't assume it in general.) The previous check accidentally covered that issue, because no RECORD types ever have OIDs, while if two tupdescs have the same named composite type OID then, a fortiori, they have the same tdhasoid setting. If we're removing the type OID match check then we'd better include tdhasoid match as part of the physical compatibility check. Without that hack in tupconvert.c, we need ExecEvalConvertRowtype to take responsibility for inserting the correct rowtype OID label whenever tupconvert.c decides it need not do anything. This is easily done with heap_copy_tuple_as_datum, which will be considerably faster than a tuple disassembly and reassembly anyway; so from a performance standpoint this change is a win all around compared to what happened in earlier branches. It just means a couple more lines of code in ExecEvalConvertRowtype. Ashutosh Bapat and Tom Lane Discussion: https://postgr.es/m/CAFjFpRfvHABV6+oVvGcshF8rHn+1LfRUhj7Jz1CDZ4gPUwehBg@mail.gmail.com
2017-04-06Allow avoiding tuple copy within tuplesort_gettupleslot().Andres Freund
Add a "copy" argument to make it optional to receive a copy of caller tuple that is safe to use following a subsequent manipulating of tuplesort's state. This is a performance optimization. Most existing tuplesort_gettupleslot() callers are made to opt out of copying. Existing callers that happen to rely on the validity of tuple memory beyond subsequent manipulations of the tuplesort request their own copy. This brings tuplesort_gettupleslot() in line with tuplestore_gettupleslot(). In the future, a "copy" tuplesort_getdatum() argument may be added, that similarly allows callers to opt out of receiving their own copy of tuple. In passing, clarify assumptions that callers of other tuplesort fetch routines may make about tuple memory validity, per gripe from Tom Lane. Author: Peter Geoghegan Discussion: CAM3SWZQWZZ_N=DmmL7tKy_OUjGH_5mN=N=A6h7kHyyDvEhg2DA@mail.gmail.com
2017-04-06Identity columnsPeter Eisentraut
This is the SQL standard-conforming variant of PostgreSQL's serial columns. It fixes a few usability issues that serial columns have: - CREATE TABLE / LIKE copies default but refers to same sequence - cannot add/drop serialness with ALTER TABLE - dropping default does not drop sequence - need to grant separate privileges to sequence - other slight weirdnesses because serial is some kind of special macro Reviewed-by: Vitaly Burovoy <[email protected]>
2017-04-05Capitalize names of PLs consistentlyPeter Eisentraut
Author: Daniel Gustafsson <[email protected]>
2017-04-04Follow-on cleanup for the transition table patch.Kevin Grittner
Commit 59702716 added transition table support to PL/pgsql so that SQL queries in trigger functions could access those transient tables. In order to provide the same level of support for PL/perl, PL/python and PL/tcl, refactor the relevant code into a new function SPI_register_trigger_data. Call the new function in the trigger handler of all four PLs, and document it as a public SPI function so that authors of out-of-tree PLs can do the same. Also get rid of a second QueryEnvironment object that was maintained by PL/pgsql. That was previously used to deal with cursors, but the same approach wasn't appropriate for PLs that are less tangled up with core code. Instead, have SPI_cursor_open install the connection's current QueryEnvironment, as already happens for SPI_execute_plan. While in the docs, remove the note that transition tables were only supported in C and PL/pgSQL triggers, and correct some ommissions. Thomas Munro with some work by Kevin Grittner (mostly docs)
2017-04-04Fix thinko in BitmapAdjustPrefetchIterator.Robert Haas
Dilip Kumar Discussion: http://postgr.es/m/CAFiTN-uKAvRhWprb0i-U9zFOekgQRRwqjP1wvOBsKZb-UEKbug@mail.gmail.com
2017-04-01Fix two undocumented parameters to functions from ENR patch.Kevin Grittner
On ProcessUtility document the parameter, to match others. On CreateCachedPlan drop the queryEnv parameter. It was not referenced within the function, and had been added on the assumption that with some unknown future usage of QueryEnvironment it might be useful to do something there. We have avoided other "just in case" implementation of unused paramters, so drop it here. Per gripe from Tom Lane
2017-04-01Add infrastructure to support EphemeralNamedRelation references.Kevin Grittner
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
2017-04-01Avoid GatherMerge crash when there are no workers.Robert Haas
It's unnecessary to return an actual slot when we have no tuple. We can just return NULL, which avoids the risk of indexing into an array that might not contain any elements. Rushabh Lathia, per a report from Tomas Vondra Discussion: http://postgr.es/m/[email protected]
2017-03-28Make new expression eval code reject references to dropped columns.Tom Lane
Formerly, a Var referencing an already-dropped column was allowed and would always produce a NULL value. However, that behavior was implemented in slot_getattr which the new expression code doesn't use; thus there is now a risk of returning theoretically-deleted data. We had regression test cases that purported to exercise this, but they failed to expose any problem, apparently because plpgsql filters the dropped column and produces an output tuple that has a NULL there already. Ideally the DROP or ALTER attempt in these test cases would get rejected due to dependency checks; but until that happens, let's modify the behavior so that we fail the query during executor start. This was already true for the related case of a column having changed type underneath us, and there's no obvious reason why we need to be laxer for dropped columns. In passing, adjust the error messages in CheckVarSlotCompatibility to include the composite type name. In the cases shown in the regression tests this is always just "record", but it should be more useful in actual stale-plan cases, where the slot tupdesc would be a table's tupdesc directly. Discussion: https://postgr.es/m/[email protected]
2017-03-27Support hashed aggregation with grouping sets.Andrew Gierth
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/[email protected]
2017-03-26Improve performance of ExecEvalWholeRowVar.Tom Lane
In commit b8d7f053c, we needed to fix ExecEvalWholeRowVar to not change the state of the slot it's copying. The initial quick hack at that required two rounds of tuple construction, which is not very nice. To fix, add another primitive to tuptoaster.c that does precisely what we need. (I initially tried to do this by refactoring one of the existing functions into two pieces; but it looked like that might hurt performance for the existing case, and the amount of code that could be shared is not very large, so I gave up on that.) Discussion: https://postgr.es/m/[email protected]
2017-03-26Improve implementation of EEOP_BOOLTEST_* opcodes.Tom Lane
Both Andres and I were happy with "*op->resvalue = *op->resvalue;", but Coverity isn't; and it has a point, because some compilers might not be smart enough to elide that. So remove it. In passing, also avoid doing unnecessary assignments to *op->resnull when it's already known to have the right value.
2017-03-25Remove unreachable code in expression evaluation.Andres Freund
The previous code still contained expression evaluation time support for CaseExprs without a defresult. But transformCaseExpr() creates a default expression if necessary. Author: Andres Freund Discussion: https://postgr.es/m/[email protected]
2017-03-25git rm execQual.cTom Lane
Should have been in commit b8d7f053c5c2bf2a7e8734fe3327f6a8bc711755, but passing the patch back and forth as a patch seems to have dropped that metadata.
2017-03-25Faster expression evaluation and targetlist projection.Andres Freund
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/[email protected]
2017-03-24Improve access to parallel query from procedural languages.Robert Haas
In SQL, the ability to use parallel query was previous contingent on fcache->readonly_func, which is only set for non-volatile functions; but the volatility of a function has no bearing on whether queries inside it can use parallelism. Remove that condition. SPI_execute and SPI_execute_with_args always run the plan just once, though not necessarily to completion. Given the changes in commit 691b8d59281b5177f16fe80858df921f77a8e955, it's sensible to pass CURSOR_OPT_PARALLEL_OK here, so do that. This improves access to parallelism for any caller that uses these functions to execute queries. Such callers include plperl, plpython, pltcl, and plpgsql, though it's not the case that they all use these functions exclusively. In plpgsql, allow parallel query for plain SELECT queries (as opposed to PERFORM, which already worked) and for plain expressions (which probably won't go through the executor at all, because they will likely be simple expressions, but if they do then this helps). Rafia Sabih and Robert Haas, reviewed by Dilip Kumar and Amit Kapila Discussion: http://postgr.es/m/CAOGQiiMfJ+4SQwgG=6CVHWoisiU0+7jtXSuiyXBM3y=A=eJzmg@mail.gmail.com
2017-03-23Allow for parallel execution whenever ExecutorRun() is done only once.Robert Haas
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
2017-03-21Don't scan partitioned tables.Robert Haas
Partitioned tables do not contain any data; only their unpartitioned descendents need to be scanned. However, the partitioned tables still need to be locked, even though they're not scanned. To make that work, Append and MergeAppend relations now need to carry a list of (unscanned) partitioned relations that must be locked, and InitPlan must lock all partitioned result relations. Aside from the obvious advantage of avoiding some work at execution time, this has two other advantages. First, it may improve the planner's decision-making in some cases since the empty relation might throw things off. Second, it paves the way to getting rid of the storage for partitioned tables altogether. Amit Langote, reviewed by me. Discussion: http://postgr.es/m/[email protected]
2017-03-14Spelling fixesPeter Eisentraut
From: Josh Soref <[email protected]>
2017-03-12Use wrappers of PG_DETOAST_DATUM_PACKED() more.Noah Misch
This makes almost all core code follow the policy introduced in the previous commit. Specific decisions: - Text search support functions with char* and length arguments, such as prsstart and lexize, may receive unaligned strings. I doubt maintainers of non-core text search code will notice. - Use plain VARDATA() on values detoasted or synthesized earlier in the same function. Use VARDATA_ANY() on varlenas sourced outside the function, even if they happen to always have four-byte headers. As an exception, retain the universal practice of using VARDATA() on return values of SendFunctionCall(). - Retain PG_GETARG_BYTEA_P() in pageinspect. (Page images are too large for a one-byte header, so this misses no optimization.) Sites that do not call get_page_from_raw() typically need the four-byte alignment. - For now, do not change btree_gist. Its use of four-byte headers in memory is partly entangled with storage of 4-byte headers inside GBT_VARKEY, on disk. - For now, do not change gtrgm_consistent() or gtrgm_distance(). They incorporate the varlena header into a cache, and there are multiple credible implementation strategies to consider.
2017-03-12Remove dead code in nodeGatherMerge.c.Tom Lane
Coverity noted that the last line of gather_merge_getnext() was unreachable, since each arm of the preceding "if" ends in a "return". Drop it as an oversight. In passing, improve some nearby comments.
2017-03-11Improve expression evaluation test coverage.Andres Freund
Upcoming patches are revamping expression evaluation significantly. It therefore seems prudent to try to ensure that the coverage of the existing evaluation code is high. This commit adds coverage for the cases that can reasonably be tested. There's still a bunch of unreachable error messages and such, but otherwise this achieves nearly full regression test coverage (with the exception of the unused GetAttributeByNum/GetAttributeByName). Author: Andres Freund Discussion: https://postgr.es/m/[email protected]
2017-03-09Add a Gather Merge executor node.Robert Haas
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
2017-03-08Silence compiler warnings in BitmapHeapNext().Tom Lane
Same disease as 270d7dd8a5a7128fc2b859f3bf95e2c1fb45be79.
2017-03-08Support parallel bitmap heap scans.Robert Haas
The index is scanned by a single process, but then all cooperating processes can iterate jointly over the resulting set of heap blocks. In the future, we might also want to support using a parallel bitmap index scan to set up for a parallel bitmap heap scan, but that's a job for another day. Dilip Kumar, with some corrections and cosmetic changes by me. The larger patch set of which this is a part has been reviewed and tested by (at least) Andres Freund, Amit Khandekar, Tushar Ahuja, Rafia Sabih, Haribabu Kommi, Thomas Munro, and me. Discussion: http://postgr.es/m/CAFiTN-uc4=0WxRGfCzs-xfkMYcSEWUC-Fon6thkJGjkh9i=13A@mail.gmail.com
2017-03-08Support XMLTABLE query expressionAlvaro Herrera
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
2017-03-08Fix parallel index and index-only scans to fall back to serial.Robert Haas
Parallel executor nodes can't assume that parallel execution will happen in every case where the plan calls for it, because it might not work out that way. However, parallel index scan and parallel index-only scan failed to do the right thing here. Repair. Amit Kapila, per a report from me. Discussion: http://postgr.es/m/CAA4eK1Kq5qb_u2AOoda5XBB91vVWz90w=LgtRLgsssriS8pVTw@mail.gmail.com
2017-03-08tidbitmap: Support shared iteration.Robert Haas
When a shared iterator is used, each call to tbm_shared_iterate() returns a result that has not yet been returned to any process attached to the shared iterator. In other words, each cooperating processes gets a disjoint subset of the full result set, but all results are returned exactly once. This is infrastructure for parallel bitmap heap scan. Dilip Kumar. The larger patch set of which this is a part has been reviewed and tested by (at least) Andres Freund, Amit Khandekar, Tushar Ahuja, Rafia Sabih, Haribabu Kommi, and Thomas Munro. Discussion: http://postgr.es/m/CAFiTN-uc4=0WxRGfCzs-xfkMYcSEWUC-Fon6thkJGjkh9i=13A@mail.gmail.com
2017-03-03Improve error reporting for tuple-routing failures.Robert Haas
Currently, the whole row is shown without column names. Instead, adopt a style similar to _bt_check_unique() in ExecFindPartition() and show the failing key: (key1, ...) = (val1, ...). Amit Langote, per a complaint from Simon Riggs. Reviewed by me; I also adjusted the grammar in one of the comments. Discussion: http://postgr.es/m/[email protected]
2017-03-02Refactor bitmap heap scan in preparation for parallel support.Robert Haas
The final patch will be less messy if the prefetching support is a bit better isolated, so do that. Dilip Kumar, with some changes by me. The larger patch set of which this is a part has been reviewed and tested by (at least) Andres Freund, Amit Khandekar, Tushar Ahuja, Rafia Sabih, Haribabu Kommi, and Thomas Munro.
2017-02-28Use proper enum constants for LockWaitPolicyPeter Eisentraut
2017-02-27Allow index AMs to return either HeapTuple or IndexTuple format during IOS.Tom Lane
Previously, only IndexTuple format was supported for the output data of an index-only scan. This is fine for btree, which is just returning a verbatim index tuple anyway. It's not so fine for SP-GiST, which can return reconstructed data that's much larger than a page. To fix, extend the index AM API so that index-only scan data can be returned in either HeapTuple or IndexTuple format. There's other ways we could have done it, but this way avoids an API break for index AMs that aren't concerned with the issue, and it costs little except a couple more fields in IndexScanDescs. I changed both GiST and SP-GiST to use the HeapTuple method. I'm not very clear on whether GiST can reconstruct data that's too large for an IndexTuple, but that seems possible, and it's not much of a code change to fix. Per a complaint from Vik Fearing. Reviewed by Jason Li. Discussion: https://postgr.es/m/[email protected]
2017-02-26Allow custom and foreign scans to have shutdown callbacks.Robert Haas
This is expected to be useful mostly when performing such scans in parallel, because in that case it allows (in combination with commit acf555bc53acb589b5a2827e65d655fa8c9adee0) nodes below a Gather to get control just before the DSM segment goes away. KaiGai Kohei, except that I rewrote the documentation. Reviewed by Claudio Freire. Discussion: http://postgr.es/m/CADyhKSXJK0jUJ8rWv4AmKDhsUh124_rEn39eqgfC5D8fu6xVuw@mail.gmail.com
2017-02-23Consistently declare timestamp variables as TimestampTz.Tom Lane
Twiddle the replication-related code so that its timestamp variables are declared TimestampTz, rather than the uninformative "int64" that was previously used for meant-to-be-always-integer timestamps. This resolves the int64-vs-TimestampTz declaration inconsistencies introduced by commit 7c030783a, though in the opposite direction to what was originally suggested. This required including datatype/timestamp.h in a couple more places than before. I decided it would be a good idea to slim down that header by not having it pull in <float.h> etc, as those headers are no longer at all relevant to its purpose. Unsurprisingly, a small number of .c files turn out to have been depending on those inclusions, so add them back in the .c files as needed. Discussion: https://postgr.es/m/[email protected] Discussion: https://postgr.es/m/[email protected]
2017-02-22Pass the source text for a parallel query to the workers.Robert Haas
With this change, you can see the query that a parallel worker is executing in pg_stat_activity, and if the worker crashes you can see what query it was executing when it crashed. Rafia Sabih, reviewed by Kuntal Ghosh and Amit Kapila and slightly revised by me.
2017-02-22Shut down Gather's children before shutting down Gather itself.Robert Haas
It turns out that the original shutdown order here does not work well. Multiple people attempting to develop further parallel query patches have discovered that they need to do cleanup before the DSM goes away, and you can't do that if the parent node gets cleaned up first. Patch by me, reviewed by KaiGai Kohei and Dilip Kumar. Discussion: http://postgr.es/m/CA+TgmoY6bOc1YnhcAQnMfCBDbsJzROQ3sYxSAL-SYB5tMJcTKg@mail.gmail.com Discussion: http://postgr.es/m/[email protected] Discussion: http://postgr.es/m/CA+TgmoYuPOc=+xrG1v0fCsoLbKAab9F1ddOeaaiLMzKOiBar1Q@mail.gmail.com
2017-02-19Add optimizer and executor support for parallel index-only scans.Robert Haas
Commit 5262f7a4fc44f651241d2ff1fa688dd664a34874 added similar support for parallel index scans; this extends that work to index-only scans. As with parallel index scans, this requires support from the index AM, so currently parallel index-only scans will only be possible for btree indexes. Rafia Sabih, reviewed and tested by Rahila Syed, Tushar Ahuja, and Amit Kapila Discussion: http://postgr.es/m/CAOGQiiPEAs4C=TBp0XShxBvnWXuzGL2u++Hm1=qnCpd6_Mf8Fw@mail.gmail.com
2017-02-15Make sure that hash join's bulk-tuple-transfer loops are interruptible.Tom Lane
The loops in ExecHashJoinNewBatch(), ExecHashIncreaseNumBatches(), and ExecHashRemoveNextSkewBucket() are all capable of iterating over many tuples without ever doing a CHECK_FOR_INTERRUPTS, so that the backend might fail to respond to SIGINT or SIGTERM for an unreasonably long time. Fix that. In the case of ExecHashJoinNewBatch(), it seems useful to put the added CHECK_FOR_INTERRUPTS into ExecHashJoinGetSavedTuple() rather than directly in the loop, because that will also ensure that both principal code paths through ExecHashJoinOuterGetTuple() will do a CHECK_FOR_INTERRUPTS, which seems like a good idea to avoid surprises. Back-patch to all supported branches. Tom Lane and Thomas Munro Discussion: https://postgr.es/m/[email protected]
2017-02-15Add optimizer and executor support for parallel index scans.Robert Haas
In combination with 569174f1be92be93f5366212cc46960d28a5c5cd, which taught the btree AM how to perform parallel index scans, this allows parallel index scan plans on btree indexes. This infrastructure should be general enough to support parallel index scans for other index AMs as well, if someone updates them to support parallel scans. Amit Kapila, reviewed and tested by Anastasia Lubennikova, Tushar Ahuja, and Haribabu Kommi, and me.
2017-02-14Allow parallel workers to execute subplans.Robert Haas
This doesn't do anything to make Param nodes anything other than parallel-restricted, so this only helps with uncorrelated subplans, and it's not necessarily very cheap because each worker will run the subplan separately (just as a Hash Join will build a separate copy of the hash table in each participating process), but it's a first step toward supporting cases that are more likely to help in practice, and is occasionally useful on its own. Amit Kapila, reviewed and tested by Rafia Sabih, Dilip Kumar, and me. Discussion: http://postgr.es/m/CAA4eK1+e8Z45D2n+rnDMDYsVEb5iW7jqaCH_tvPMYau=1Rru9w@mail.gmail.com
2017-02-09simplehash: Additional tweaks to make specifying an allocator work.Robert Haas
Even if we don't emit definitions for SH_ALLOCATE and SH_FREE, we still need prototypes. The user can't define them before including simplehash.h because SH_TYPE isn't available yet. For the allocator to be able to access private_data, it needs to become an argument to SH_CREATE. Previously we relied on callers to set that after returning from SH_CREATE, but SH_CREATE calls SH_ALLOCATE before returning. Dilip Kumar, reviewed by me.
2017-02-09Allow index AMs to cache data across aminsert calls within a SQL command.Tom Lane
It's always been possible for index AMs to cache data across successive amgettuple calls within a single SQL command: the IndexScanDesc.opaque field is meant for precisely that. However, no comparable facility exists for amortizing setup work across successive aminsert calls. This patch adds such a feature and teaches GIN, GIST, and BRIN to use it to amortize catalog lookups they'd previously been doing on every call. (The other standard index AMs keep everything they need in the relcache, so there's little to improve there.) For GIN, the overall improvement in a statement that inserts many rows can be as much as 10%, though it seems a bit less for the other two. In addition, this makes a really significant difference in runtime for CLOBBER_CACHE_ALWAYS tests, since in those builds the repeated catalog lookups are vastly more expensive. The reason this has been hard up to now is that the aminsert function is not passed any useful place to cache per-statement data. What I chose to do is to add suitable fields to struct IndexInfo and pass that to aminsert. That's not widening the index AM API very much because IndexInfo is already within the ken of ambuild; in fact, by passing the same info to aminsert as to ambuild, this is really removing an inconsistency in the AM API. Discussion: https://postgr.es/m/[email protected]
2017-02-07Revise the way the element allocator for a simplehash is specified.Robert Haas
This method is more elegant and more efficient. Per a suggestion from Andres Freund, who also briefly reviewed the patch.
2017-02-07Allow the element allocator for a simplehash to be specified.Robert Haas
This is infrastructure for a pending patch to allow parallel bitmap heap scans. Dilip Kumar, reviewed (in earlier versions) by Andres Freund and (more recently) by me. Some further renaming by me, also.
2017-02-06Fix typos in comments.Heikki Linnakangas
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
2017-02-04Remove redundant comment.Robert Haas
Rafia Sabih
2017-01-27Use castNode() in a bunch of statement-list-related code.Tom Lane
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.