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* Avoid crash with WHERE CURRENT OF and a custom scan plan.Tom Lane2021-01-18
| | | | | | | | | | | | | | | | | | | | | | | execCurrent.c's search_plan_tree() assumed that ForeignScanStates and CustomScanStates necessarily have a valid ss_currentRelation. This is demonstrably untrue for postgres_fdw's remote join and remote aggregation plans, and non-leaf custom scans might not have an identifiable scan relation either. Avoid crashing by ignoring such nodes when the field is null. This solution will lead to errors like 'cursor "foo" is not a simply updatable scan of table "bar"' in cases where maybe we could have allowed WHERE CURRENT OF to work. That's not an issue for postgres_fdw's usages, since joins or aggregations would render WHERE CURRENT OF invalid anyway. But an otherwise-transparent upper level custom scan node might find this annoying. When and if someone cares to expend work on such a scenario, we could invent a custom-scan-provider callback to determine what's safe. Report and patch by David Geier, commentary by me. It's been like this for awhile, so back-patch to all supported branches. Discussion: https://postgr.es/m/0253344d-9bdd-11c4-7f0d-d88c02cd7991@swarm64.com
* Fix bug #16784 in Disk-based Hash Aggregation.Jeff Davis2020-12-26
| | | | | | | | | | | | | | | | | Before processing tuples, agg_refill_hash_table() was setting all pergroup pointers to NULL to signal to advance_aggregates() that it should not attempt to advance groups that had spilled. The problem was that it also set the pergroups for sorted grouping sets to NULL, which caused rescanning to fail. Instead, change agg_refill_hash_table() to only set the pergroups for hashed grouping sets to NULL; and when compiling the expression, pass doSort=false. Reported-by: Alexander Lakhin Discussion: https://postgr.es/m/16784-7ff169bf2c3d1588%40postgresql.org Backpatch-through: 13
* Properly check index mark/restore in ExecSupportsMarkRestore.Andrew Gierth2020-11-24
| | | | | | | | | | | | | | | | Previously this code assumed that all IndexScan nodes supported mark/restore, which is not true since it depends on optional index AM support functions. This could lead to errors about missing support functions in rare edge cases of mergejoins with no sort keys, where an unordered non-btree index scan was placed on the inner path without a protecting Materialize node. (Normally, the fact that merge join requires ordered input would avoid this error.) Backpatch all the way since this bug is ancient. Per report from Eugen Konkov on irc. Discussion: https://postgr.es/m/87o8jn50be.fsf@news-spur.riddles.org.uk
* Skip allocating hash table in EXPLAIN-only mode.Heikki Linnakangas2020-11-20
| | | | | | | | This is a backpatch of commit 2cccb627f1, backpatched due to popular demand. Backpatch to all supported versions. Author: Alexey Bashtanov Discussion: https://www.postgresql.org/message-id/36823f65-050d-ae24-aa4d-a37726998240%40imap.cc
* In INSERT/UPDATE, use the table's real tuple descriptor as target.Tom Lane2020-11-08
| | | | | | | | | | | | | | | | | | | | | | | This back-patches commit 20d3fe900 into the v12 and v13 branches. At the time I thought that commit was not fixing any observable bug, but Bertrand Drouvot showed otherwise: adding a dropped column to the previously-considered scenario crashes v12 and v13, unless the dropped column happens to be an integer. That is, of course, because the tupdesc we derive from the plan output tlist fails to describe the dropped column accurately, so that we'll do the wrong thing with a tuple in which that column isn't NULL. There is no bug in pre-v12 branches because they already did use the table's real tuple descriptor for any trigger-returned tuple. It seems that this set of bugs can be blamed on the changes that removed es_trig_tuple_slot, though I've not attempted to pin that down precisely. Although there's no code change needed in HEAD, update the test case to include a dropped column there too. Discussion: https://postgr.es/m/db5d97c8-f48a-51e2-7b08-b73d5434d425@amazon.com Discussion: https://postgr.es/m/16644-5da7ef98a7ac4545@postgresql.org
* Use INT64_FORMAT to print int64 variables in sort debugTomas Vondra2020-11-03
| | | | | | | | | | Commit 6ee3b5fb99 cleaned up most of the long/int64 confusion related to incremental sort, but the sort debug messages were still using %ld for int64 variables. So fix that. Author: Haiying Tang Backpatch-through: 13, where the incremental sort code was added Discussion: https://postgr.es/m/4250be9d350c4992abb722a76e288aef%40G08CNEXMBPEKD05.g08.fujitsu.local
* Guard against core dump from uninitialized subplan.Tom Lane2020-11-03
| | | | | | | | | | | | | | If the planner erroneously puts a non-parallel-safe SubPlan into a parallelized portion of the query tree, nodeSubplan.c will fail in the worker processes because it finds a null in es_subplanstates, which it's unable to cope with. It seems worth a test-and-elog to make that an error case rather than a core dump case. This probably should have been included in commit 16ebab688, which was responsible for allowing nulls to appear in es_subplanstates to begin with. So, back-patch to v10 where that came in. Discussion: https://postgr.es/m/924226.1604422326@sss.pgh.pa.us
* Fix list-munging bug that broke SQL function result coercions.Tom Lane2020-10-19
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Since commit 913bbd88d, check_sql_fn_retval() can either insert type coercion steps in-line in the Query that produces the SQL function's results, or generate a new top-level Query to perform the coercions, if modifying the Query's output in-place wouldn't be safe. However, it appears that the latter case has never actually worked, because the code tried to inject the new Query back into the query list it was passed ... which is not the list that will be used for later processing when we execute the SQL function "normally" (without inlining it). So we ended up with no coercion happening at run-time, leading to wrong results or crashes depending on the datatypes involved. While the regression tests look like they cover this area well enough, through a huge bit of bad luck all the test cases that exercise the separate-Query path were checking either inline-able cases (which accidentally didn't have the bug) or cases that are no-ops at runtime (e.g., varchar to text), so that the failure to perform the coercion wasn't obvious. The fact that the cases that don't work weren't allowed at all before v13 probably contributed to not noticing the problem sooner, too. To fix, get rid of the separate "flat" list of Query nodes and instead pass the real two-level list that is going to be used later. I chose to make the same change in check_sql_fn_statements(), although that has no actual bug, just so that we don't need that data structure at all. This is an API change, as evidenced by the adjustments needed to callers outside functions.c. That's a bit scary to be doing in a released branch, but so far as I can tell from a quick search, there are no outside callers of these functions (and they are sufficiently specific to our semantics for SQL-language functions that it's not apparent why any extension would need to call them). In any case, v13 already changed the API of check_sql_fn_retval() compared to prior branches. Per report from pinker. Back-patch to v13 where this code came in. Discussion: https://postgr.es/m/1603050466566-0.post@n3.nabble.com
* Change LogicalTapeSetBlocks() to use nBlocksWritten.Jeff Davis2020-09-15
| | | | | | | | | | | | | Previously, it was based on nBlocksAllocated to account for tapes with open write buffers that may not have made it to the BufFile yet. That was unnecessary, because callers do not need to get the number of blocks while a tape has an open write buffer; and it also conflicted with the preallocation logic added for HashAgg. Reviewed-by: Peter Geoghegan Discussion: https://postgr.es/m/ce5af05900fdbd0e9185747825a7423c48501964.camel@j-davis.com Backpatch-through: 13
* HashAgg: release write buffers sooner by rewinding tape.Jeff Davis2020-09-15
| | | | | | | | | | This was an oversight. The purpose of 7fdd919ae7 was to avoid keeping tape buffers around unnecessisarily, but HashAgg didn't rewind early enough. Reviewed-by: Peter Geoghegan Discussion: https://postgr.es/m/1fb1151c2cddf8747d14e0532da283c3f97e2685.camel@j-davis.com Backpatch-through: 13
* logtape.c: do not preallocate for tapes when sortingJeff Davis2020-09-11
| | | | | | | | | | | The preallocation logic is only useful for HashAgg, so disable it when sorting. Also, adjust an out-of-date comment. Reviewed-by: Peter Geoghegan Discussion: https://postgr.es/m/CAH2-Wzn_o7tE2+hRVvwSFghRb75AJ5g-nqGzDUqLYMexjOAe=g@mail.gmail.com Backpatch-through: 13
* Check default partitions constraints while descendingAlvaro Herrera2020-09-08
| | | | | | | | | | | | | | | | | | | | | | | Partitioning tuple route code assumes that the partition chosen while descending the partition hierarchy is always the correct one. This is true except when the partition is the default partition and another partition has been added concurrently: the partition constraint changes and we don't recheck it. This can lead to tuples mistakenly being added to the default partition that should have been rejected. Fix by rechecking the default partition constraint while descending the hierarchy. An isolation test based on the reproduction steps described by Hao Wu (with tweaks for extra coverage) is included. Backpatch to 12, where this bug came in with 898e5e3290a7. Reported by: Hao Wu <hawu@vmware.com> Author: Amit Langote <amitlangote09@gmail.com> Author: Álvaro Herrera <alvherre@alvh.no-ip.org> Discussion: https://postgr.es/m/CA+HiwqFqBmcSSap4sFnCBUEL_VfOMmEKaQ3gwUhyfa4c7J_-nA@mail.gmail.com Discussion: https://postgr.es/m/DM5PR0501MB3910E97A9EDFB4C775CF3D75A42F0@DM5PR0501MB3910.namprd05.prod.outlook.com
* Be more careful about the shape of hashable subplan clauses.Tom Lane2020-08-14
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | nodeSubplan.c expects that the testexpr for a hashable ANY SubPlan has the form of one or more OpExprs whose LHS is an expression of the outer query's, while the RHS is an expression over Params representing output columns of the subquery. However, the planner only went as far as verifying that the clauses were all binary OpExprs. This works 99.99% of the time, because the clauses have the right shape when emitted by the parser --- but it's possible for function inlining to break that, as reported by PegoraroF10. To fix, teach the planner to check that the LHS and RHS contain the right things, or more accurately don't contain the wrong things. Given that this has been broken for years without anyone noticing, it seems sufficient to just give up hashing when it happens, rather than go to the trouble of commuting the clauses back again (which wouldn't necessarily work anyway). While poking at that, I also noticed that nodeSubplan.c had a baked-in assumption that the number of hash clauses is identical to the number of subquery output columns. Again, that's fine as far as parser output goes, but it's not hard to break it via function inlining. There seems little reason for that assumption though --- AFAICS, the only thing it's buying us is not having to store the number of hash clauses explicitly. Adding code to the planner to reject such cases would take more code than getting nodeSubplan.c to cope, so I fixed it that way. This has been broken for as long as we've had hashable SubPlans, so back-patch to all supported branches. Discussion: https://postgr.es/m/1549209182255-0.post@n3.nabble.com
* Fix matching of sub-partitions when a partitioned plan is stale.Tom Lane2020-08-05
| | | | | | | | | | | | | | | | | | | | | | | | | | | | Since we no longer require AccessExclusiveLock to add a partition, the executor may see that a partitioned table has more partitions than the planner saw. ExecCreatePartitionPruneState's code for matching up the partition lists in such cases was faulty, and would misbehave if the planner had successfully pruned any partitions from the query. (Thus, trouble would occur only if a partition addition happens concurrently with a query that uses both static and dynamic partition pruning.) This led to an Assert failure in debug builds, and probably to crashes or query misbehavior in production builds. To repair the bug, just explicitly skip zeroes in the plan's relid_map[] list. I also made some cosmetic changes to make the code more readable (IMO anyway). Also, convert the cross-checking Assert to a regular test-and-elog, since it's now apparent that this logic is more fragile than one would like. Currently, there's no way to repeatably exercise this code, except with manual use of a debugger to stop the backend between planning and execution. Hence, no test case in this patch. We oughta do something about that testability gap, but that's for another day. Amit Langote and Tom Lane, per report from Justin Pryzby. Oversight in commit 898e5e329; backpatch to v12 where that appeared. Discussion: https://postgr.es/m/20200802181131.GA27754@telsasoft.com
* Add hash_mem_multiplier GUC.Peter Geoghegan2020-07-29
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Add a GUC that acts as a multiplier on work_mem. It gets applied when sizing executor node hash tables that were previously size constrained using work_mem alone. The new GUC can be used to preferentially give hash-based nodes more memory than the generic work_mem limit. It is intended to enable admin tuning of the executor's memory usage. Overall system throughput and system responsiveness can be improved by giving hash-based executor nodes more memory (especially over sort-based alternatives, which are often much less sensitive to being memory constrained). The default value for hash_mem_multiplier is 1.0, which is also the minimum valid value. This means that hash-based nodes continue to apply work_mem in the traditional way by default. hash_mem_multiplier is generally useful. However, it is being added now due to concerns about hash aggregate performance stability for users that upgrade to Postgres 13 (which added disk-based hash aggregation in commit 1f39bce0). While the old hash aggregate behavior risked out-of-memory errors, it is nevertheless likely that many users actually benefited. Hash agg's previous indifference to work_mem during query execution was not just faster; it also accidentally made aggregation resilient to grouping estimate problems (at least in cases where this didn't create destabilizing memory pressure). hash_mem_multiplier can provide a certain kind of continuity with the behavior of Postgres 12 hash aggregates in cases where the planner incorrectly estimates that all groups (plus related allocations) will fit in work_mem/hash_mem. This seems necessary because hash-based aggregation is usually much slower when only a small fraction of all groups can fit. Even when it isn't possible to totally avoid hash aggregates that spill, giving hash aggregation more memory will reliably improve performance (the same cannot be said for external sort operations, which appear to be almost unaffected by memory availability provided it's at least possible to get a single merge pass). The PostgreSQL 13 release notes should advise users that increasing hash_mem_multiplier can help with performance regressions associated with hash aggregation. That can be taken care of by a later commit. Author: Peter Geoghegan Reviewed-By: Álvaro Herrera, Jeff Davis Discussion: https://postgr.es/m/20200625203629.7m6yvut7eqblgmfo@alap3.anarazel.de Discussion: https://postgr.es/m/CAH2-WzmD%2Bi1pG6rc1%2BCjc4V6EaFJ_qSuKCCHVnH%3DoruqD-zqow%40mail.gmail.com Backpatch: 13-, where disk-based hash aggregation was introduced.
* HashAgg: use better cardinality estimate for recursive spilling.Jeff Davis2020-07-28
| | | | | | | | | | | | | | | | Use HyperLogLog to estimate the group cardinality in a spilled partition. This estimate is used to choose the number of partitions if we recurse. The previous behavior was to use the number of tuples in a spilled partition as the estimate for the number of groups, which lead to overpartitioning. That could cause the number of batches to be much higher than expected (with each batch being very small), which made it harder to interpret EXPLAIN ANALYZE results. Reviewed-by: Peter Geoghegan Discussion: https://postgr.es/m/a856635f9284bc36f7a77d02f47bbb6aaf7b59b3.camel@j-davis.com Backpatch-through: 13
* Rename another "hash_mem" local variable.Peter Geoghegan2020-07-28
| | | | | | Missed by my commit 564ce621. Backpatch: 13-, where disk-based hash aggregation was introduced.
* Make EXPLAIN ANALYZE of HashAgg more similar to Hash JoinDavid Rowley2020-07-29
| | | | | | | | | | | | | | | | | | | | | | | | | There were various unnecessary differences between Hash Agg's EXPLAIN ANALYZE output and Hash Join's. Here we modify the Hash Agg output so that it's better aligned to Hash Join's. The following changes have been made: 1. Start batches counter at 1 instead of 0. 2. Always display the "Batches" property, even when we didn't spill to disk. 3. Use the text "Batches" instead of "HashAgg Batches" for text format. 4. Use the text "Memory Usage" instead of "Peak Memory Usage" for text format. 5. Include "Batches" before "Memory Usage" in both text and non-text formats. In passing also modify the "Planned Partitions" property so that we show it regardless of if the value is 0 or not for non-text EXPLAIN formats. This was pointed out by Justin Pryzby and probably should have been part of 40efbf870. Reviewed-by: Justin Pryzby, Jeff Davis Discussion: https://postgr.es/m/CAApHDvrshRnA6C0VFnu7Fb9TVvgGo80PUMm5+2DiaS1gEkPvtw@mail.gmail.com Backpatch-through: 13, where HashAgg batching was introduced
* Fix LookupTupleHashEntryHash() pipeline-stall issue.Jeff Davis2020-07-26
| | | | | | | | Refactor hash lookups in nodeAgg.c to improve performance. Author: Andres Freund and Jeff Davis Discussion: https://postgr.es/m/20200612213715.op4ye4q7gktqvpuo%40alap3.anarazel.de Backpatch-through: 13
* Fix buffer usage stats for nodes above Gather Merge.Amit Kapila2020-07-25
| | | | | | | | | | | | | | | Commit 85c9d347 addressed a similar problem for Gather and Gather Merge nodes but forgot to account for nodes above parallel nodes. This still works for nodes above Gather node because we shut down the workers for Gather node as soon as there are no more tuples. We can do a similar thing for Gather Merge as well but it seems better to account for stats during nodes shutdown after completing the execution. Reported-by: Stéphane Lorek, Jehan-Guillaume de Rorthais Author: Jehan-Guillaume de Rorthais <jgdr@dalibo.com> Reviewed-by: Amit Kapila Backpatch-through: 10, where it was introduced Discussion: https://postgr.es/m/20200718160206.584532a2@firost
* Fix minor typo in nodeIncrementalSort.c.Amit Kapila2020-07-20
| | | | | | | Author: Vignesh C Reviewed-by: James Coleman Backpatch-through: 13, where it was introduced Discussion: https://postgr.es/m/CALDaNm0WjZqRvdeL59ZfYH0o4mLbKQ23jm-bnjXcFzgpANx55g@mail.gmail.com
* HashAgg: before spilling tuples, set unneeded columns to NULL.Jeff Davis2020-07-12
| | | | | | | | | This is a replacement for 4cad2534. Instead of projecting all tuples going into a HashAgg, only remove unnecessary attributes when actually spilling. This avoids the regression for the in-memory case. Discussion: https://postgr.es/m/a2fb7dfeb4f50aa0a123e42151ee3013933cb802.camel%40j-davis.com Backpatch-through: 13
* Fix EXPLAIN ANALYZE for parallel HashAgg plansDavid Rowley2020-06-19
| | | | | | | | | | | | | | | Since 1f39bce02, HashAgg nodes have had the ability to spill to disk when memory consumption exceeds work_mem. That commit added new properties to EXPLAIN ANALYZE to show the maximum memory usage and disk usage, however, it didn't quite go as far as showing that information for parallel workers. Since workers may have experienced something very different from the main process, we should show this information per worker, as is done in Sort. Reviewed-by: Justin Pryzby Reviewed-by: Jeff Davis Discussion: https://postgr.es/m/CAApHDvpEKbfZa18mM1TD7qV6PG+w97pwCWq5tVD0dX7e11gRJw@mail.gmail.com Backpatch-through: 13, where the hashagg spilling code was added.
* Fix buffile.c error handling.Thomas Munro2020-06-16
| | | | | | | | | | | | | | | | | | Convert buffile.c error handling to use ereport. This fixes cases where I/O errors were indistinguishable from EOF or not reported. Also remove "%m" from error messages where errno would be bogus. While we're modifying those strings, add block numbers and short read byte counts where appropriate. Back-patch to all supported releases. Reported-by: Amit Khandekar <amitdkhan.pg@gmail.com> Reviewed-by: Melanie Plageman <melanieplageman@gmail.com> Reviewed-by: Alvaro Herrera <alvherre@2ndquadrant.com> Reviewed-by: Robert Haas <robertmhaas@gmail.com> Reviewed-by: Ibrar Ahmed <ibrar.ahmad@gmail.com> Reviewed-by: Michael Paquier <michael@paquier.xyz> Discussion: https://postgr.es/m/CA%2BhUKGJE04G%3D8TLK0DLypT_27D9dR8F1RQgNp0jK6qR0tZGWOw%40mail.gmail.com
* Fix HashAgg regression from choosing too many initial buckets.Jeff Davis2020-06-08
| | | | | | | | Diagnosis by Andres. Reported-by: Pavel Stehule Discussion: https://postgr.es/m/CAFj8pRDLVakD5Aagt3yZeEQeTeEWaS3YE5h8XC3Q3qJ6TYkc2Q%40mail.gmail.com Backpatch-through: 13
* Mop-up for wait event naming issues.Tom Lane2020-05-16
| | | | | | | | | | | | Synchronize the event names for parallel hash join waits with other event names, by getting rid of the slashes and dropping "-ing" suffixes. Rename ClogGroupUpdate to XactGroupUpdate, to match the new SLRU name. Move the ProcSignalBarrier event to the IPC category; it doesn't belong under IO. Also a bit more wordsmithing in the wait event documentation tables. Discussion: https://postgr.es/m/4505.1589640417@sss.pgh.pa.us
* Run pgindent with new pg_bsd_indent version 2.1.1.Tom Lane2020-05-16
| | | | | | | | | | | Thomas Munro fixed a longstanding annoyance in pg_bsd_indent, that it would misformat lines containing IsA() macros on the assumption that the IsA() call should be treated like a cast. This improves some other cases involving field/variable names that match typedefs, too. The only places that get worse are a couple of uses of the OpenSSL macro STACK_OF(); we'll gladly take that trade-off. Discussion: https://postgr.es/m/20200114221814.GA19630@alvherre.pgsql
* Fix assertion with relation using REPLICA IDENTITY FULL in subscriberMichael Paquier2020-05-16
| | | | | | | | | | | | | | | | In a logical replication subscriber, a table using REPLICA IDENTITY FULL which has a primary key would try to use the primary key's index available to scan for a tuple, but an assertion only assumed as correct the case of an index associated to REPLICA IDENTITY USING INDEX. This commit corrects the assertion so as the use of a primary key index is a valid case. Reported-by: Dilip Kumar Analyzed-by: Dilip Kumar Author: Euler Taveira Reviewed-by: Michael Paquier, Masahiko Sawada Discussion: https://postgr.es/m/CAFiTN-u64S5bUiPL1q5kwpHNd0hRnf1OE-bzxNiOs5zo84i51w@mail.gmail.com Backpatch-through: 10
* Initial pgindent and pgperltidy run for v13.Tom Lane2020-05-14
| | | | | | | | | | | Includes some manual cleanup of places that pgindent messed up, most of which weren't per project style anyway. Notably, it seems some people didn't absorb the style rules of commit c9d297751, because there were a bunch of new occurrences of function calls with a newline just after the left paren, all with faulty expectations about how the rest of the call would get indented.
* Dial back -Wimplicit-fallthrough to level 3Alvaro Herrera2020-05-13
| | | | | | | | | The additional pain from level 4 is excessive for the gain. Also revert all the source annotation changes to their original wordings, to avoid back-patching pain. Discussion: https://postgr.es/m/31166.1589378554@sss.pgh.pa.us
* Add -Wimplicit-fallthrough to CFLAGS and CXXFLAGSAlvaro Herrera2020-05-12
| | | | | | | | | | | | | | | Use it at level 4, a bit more restrictive than the default level, and tweak our commanding comments to FALLTHROUGH. (However, leave zic.c alone, since it's external code; to avoid the warnings that would appear there, change CFLAGS for that file in the Makefile.) Author: Julien Rouhaud <rjuju123@gmail.com> Author: Álvaro Herrera <alvherre@alvh.no-ip.org> Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us> Discussion: https://postgr.es/m/20200412081825.qyo5vwwco3fv4gdo@nol Discussion: https://postgr.es/m/flat/E1fDenm-0000C8-IJ@gemulon.postgresql.org
* Fix typos and improve incremental sort commentsTomas Vondra2020-05-12
| | | | | Author: Justin Pryzby, James Coleman Discussion: https://postgr.es/m/20200419023625.GP26953@telsasoft.com
* Do no reset bounded before incremental sort rescanTomas Vondra2020-05-09
| | | | | | | | | | ExecReScanIncrementalSort was resetting bounded=false, which means the optimization would be disabled on all rescans. This happens because ExecSetTupleBound is called before the rescan, not after it. Author: James Coleman Reviewed-by: Tomas Vondra Discussion: https://postgr.es/m/20200414065336.GI1492@paquier.xyz
* Fix handling of REWIND/MARK/BACKWARD in incremental sortTomas Vondra2020-05-09
| | | | | | | | | | | | | | | | | | | | | The executor flags were not handled entirely correctly, although the bugs were mostly harmless and it was mostly comment inaccuracy. We don't need to strip any of the flags for child nodes. Incremental sort does not support backward scans of mark/restore, so MARK/BACKWARDS flags should not be possible. So we simply ensure this using an assert, and we don't bother removing them when initializing the child node. With REWIND it's a bit less clear - incremental sort does not support REWIND, but there is no way to signal this - it's legal to just ignore the flag. We however continue passing the flag to child nodes, because they might be useful to leverage that. Reported-by: Michael Paquier Author: James Coleman Reviewed-by: Tomas Vondra Discussion: https://postgr.es/m/20200414065336.GI1492@paquier.xyz
* Change the display of WAL usage statistics in Explain.Amit Kapila2020-05-05
| | | | | | | | | | | | | | | | In commit 33e05f89c5, we have added the option to display WAL usage statistics in Explain and auto_explain. The display format used two spaces between each field which is inconsistent with Buffer usage statistics which is using one space between each field. Change the format to make WAL usage statistics consistent with Buffer usage statistics. This commit also changed the usage of "full page writes" to "full page images" for WAL usage statistics to make it consistent with other parts of code and docs. Author: Julien Rouhaud, Amit Kapila Reviewed-by: Justin Pryzby, Kyotaro Horiguchi and Amit Kapila Discussion: https://postgr.es/m/CAB-hujrP8ZfUkvL5OYETipQwA=e3n7oqHFU=4ZLxWS_Cza3kQQ@mail.gmail.com
* Fix transient memory leak for SRFs in FROM.Andres Freund2020-04-22
| | | | | | | | | | | | | | | | | | | | | | | | | | | | In a9c35cf85ca I changed ExecMakeTableFunctionResult() to dynamically allocate the FunctionCallInfo used to call the SRF. Unfortunately I did not account for the fact that the surrounding memory context has query lifetime, leading to a leak till the end of the query. In most cases the leak is fairly inconsequential, but if the FunctionScan is done many times in the query, the leak can add up. This happens e.g. if the function scan is on the inner side of a nested loop, due to a lateral join. EXPLAIN SELECT sum(f) FROM generate_series(1, 100000000) g(i), generate_series(i, i+1) f; quickly shows the leak. Instead of explicitly freeing the FunctionCallInfo it seems better to make sure all the per-set temporary state in ExecMakeTableFunctionResult() is cleaned up wholesale. Currently that's probably just the FunctionCallInfo allocation, but since there's some initialization work, and since there's already an appropriate context, this seems like a more robust approach. Bug: #16112 Reported-By: Ben Cornett Author: Andres Freund Reviewed-By: Tom Lane Discussion: https://postgr.es/m/16112-4448bbf55a404189%40postgresql.org Backpatch: 12, a9c35cf85ca
* Fix minor violations of FunctionCallInvoke usage protocol.Tom Lane2020-04-21
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | Working on commit 1c455078b led me to check through FunctionCallInvoke call sites to see if every one was being honest about (a) making sure that fcinfo.isnull is initially false, and (b) checking its state after the call. Sure enough, I found some violations. The main one is that finalize_partialaggregate re-used serialfn_fcinfo without resetting isnull, even though it clearly intends to cater for serialfns that return NULL. There would only be an issue with a non-strict serialfn, since it's unlikely that a serialfn would return NULL for non-null input. We have no non-strict serialfns in core, and there may be none in the wild either, which would account for the lack of complaints. Still, it's clearly wrong, so back-patch that fix to 9.6 where finalize_partialaggregate was introduced. Also, arrayfuncs.c and rowtypes.c contained various callers that were not bothering to check for result nulls. While what's being called is a comparison or hash function that probably *shouldn't* return null, that's a lousy excuse for not having any check at all. There are existing places that just Assert(!fcinfo->isnull) in comparable situations, so I added that to the places that were calling btree comparison or hash support functions. In the places calling boolean-returning equality functions, it's quite cheap to have them treat isnull as FALSE, so make those places do that. Also remove some "locfcinfo->isnull = false" assignments that are unnecessary given the assumption that no previous call returned null. These changes seem like mostly neatnik-ism or debugging support, so I didn't back-patch.
* Fix possible crash with GENERATED ALWAYS columnsDavid Rowley2020-04-18
| | | | | | | | | | | | | | | | | | In some corner cases, this could also lead to corrupted values being included in the tuple. Users who are concerned that they are affected by this should first upgrade and then perform a base backup of their database and restore onto an off-line server. They should then query each table with generated columns to ensure there are no rows where the generated expression does not match a newly calculated version of the GENERATED ALWAYS expression. If no crashes occur and no rows are returned then you're not affected. Fixes bug #16369. Reported-by: Cameron Ezell Discussion: https://postgr.es/m/16369-5845a6f1bef59884@postgresql.org Backpatch-through: 12 (where GENERATED ALWAYS columns were added.)
* Account for collation when coercing the output of a SQL function.Tom Lane2020-04-14
| | | | | | | Commit 913bbd88d overlooked that the result of coerce_to_target_type might need collation fixups. Per report from Andreas Joseph Krogh. Discussion: https://postgr.es/m/VisenaEmail.72.37d08ec2b8cb8fb5.17179940cd3@tc7-visena
* Fix collection of typos and grammar mistakes in the tree, volume 2Michael Paquier2020-04-14
| | | | | | | | This fixes some comments and documentation new as of Postgres 13, and is a follow-up of the work done in dd0f37e. Author: Justin Pryzby Discussion: https://postgr.es/m/20200408165653.GF2228@telsasoft.com
* Cosmetic fixups for WAL usage work.Amit Kapila2020-04-13
| | | | | | | Reported-by: Justin Pryzby and Euler Taveira Author: Justin Pryzby and Julien Rouhaud Reviewed-by: Amit Kapila Discussion: https://postgr.es/m/CAB-hujrP8ZfUkvL5OYETipQwA=e3n7oqHFU=4ZLxWS_Cza3kQQ@mail.gmail.com
* Suppress -Wimplicit-fallthrough warning in new LIMIT WITH TIES code.Tom Lane2020-04-11
| | | | | | | | | | | The placement of the fall-through comment in this code appears not to work to suppress the warning in recent gcc. Move it to the bottom of the case group, and add an assertion that we didn't get there through some other code path. Also improve wording of nearby comments. Julien Rouhaud, comment hacking by me Discussion: https://postgr.es/m/CAOBaU_aLdPGU5wCpaowNLF-Q8328iR7mj1yJAhMOVsdLwY+sdg@mail.gmail.com
* Optimize RelationFindReplTupleSeq() for CLOBBER_CACHE_ALWAYS.Noah Misch2020-04-11
| | | | | | | | | Specifically, remember lookup_type_cache() results instead of retrieving them once per comparison. Under CLOBBER_CACHE_ALWAYS, this reduced src/test/subscription/t/001_rep_changes.pl elapsed time by an order of magnitude, which reduced check-world elapsed time by 9%. Discussion: https://postgr.es/m/20200406085420.GC162712@rfd.leadboat.com
* Make EXPLAIN report maximum hashtable usage across multiple rescans.Tom Lane2020-04-11
| | | | | | | | | | | | | | | Before discarding the old hash table in ExecReScanHashJoin, capture its statistics, ensuring that we report the maximum hashtable size across repeated rescans of the hash input relation. We can repurpose the existing code for reporting hashtable size in parallel workers to help with this, making the patch pretty small. This also ensures that if rescans happen within parallel workers, we get the correct maximums across all instances. Konstantin Knizhnik and Tom Lane, per diagnosis by Thomas Munro of a trouble report from Alvaro Herrera. Discussion: https://postgr.es/m/20200323165059.GA24950@alvherre.pgsql
* Clear dangling pointer to avoid bogus EXPLAIN printout in a corner case.Tom Lane2020-04-11
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | ExecReScanHashJoin will destroy the join's hash table if it expects that the inner relation will produce different rows on rescan. Up to now it's not bothered to clear the additional pointer to that hash table that exists in the child HashState node. However, it's possible for the query to terminate without building a fresh hash table (this happens if the outer relation is found to be empty during the final rescan). So we can end with a dangling pointer to a deleted hash table. That was harmless originally, but since 9.0 EXPLAIN ANALYZE has used that pointer to print hash table statistics. In debug builds this reproducibly results in garbage statistics. In non-debug builds there's frequently no ill effects, but in principle one could get wrong EXPLAIN ANALYZE output, or perhaps even a crash if free() has released the hashtable memory back to the OS. To fix, just make sure we clear the additional pointer when destroying the hash table. In problematic cases, EXPLAIN ANALYZE will then print no hashtable statistics (reverting to its pre-9.0 behavior). This isn't ideal, but since the problem manifests only in unusual corner cases, it's hard to justify taking any risks to do better in the back branches. A follow-on patch will improve matters in HEAD. Konstantin Knizhnik and Tom Lane, per diagnosis by Thomas Munro of a trouble report from Alvaro Herrera. Discussion: https://postgr.es/m/20200323165059.GA24950@alvherre.pgsql
* Fix collection of typos and grammar mistakes in the treeMichael Paquier2020-04-10
| | | | | | | This fixes some comments and documentation new as of Postgres 13. Author: Justin Pryzby Discussion: https://postgr.es/m/20200408165653.GF2228@telsasoft.com
* Allow parallel create index to accumulate buffer usage stats.Amit Kapila2020-04-09
| | | | | | | | | | | | | | Currently, we don't account for buffer usage incurred by parallel workers for parallel create index.  This commit allows each worker to record the buffer usage stats and leader backend to accumulate that stats at the end of the operation.  This will allow pg_stat_statements to display correct buffer usage stats for (parallel) create index command. Reported-by: Julien Rouhaud Author: Sawada Masahiko Reviewed-by: Dilip Kumar, Julien Rouhaud and Amit Kapila Backpatch-through: 11, where this was introduced Discussion: https://postgr.es/m/20200328151721.GB12854@nol
* Modify additional power 2 calculations to use new helper functionsDavid Rowley2020-04-08
| | | | | | | | | | | | 2nd pass of modifying various places which obtain the next power of 2 of a number and make them use the new functions added in f0705bb62. In passing, also modify num_combinations(). This can be implemented using simple bitshifting rather than looping. Reviewed-by: John Naylor Discussion: https://postgr.es/m/20200114173553.GE32763%40fetter.org
* Create memory context for HashAgg with a reasonable maxBlockSize.Jeff Davis2020-04-07
| | | | | | | | | | | | | | | | If the memory context's maxBlockSize is too big, a single block allocation can suddenly exceed work_mem. For Hash Aggregation, this can mean spilling to disk too early or reporting a confusing memory usage number for EXPLAN ANALYZE. Introduce CreateWorkExprContext(), which is like CreateExprContext(), except that it creates the AllocSet with a maxBlockSize that is reasonable in proportion to work_mem. Right now, CreateWorkExprContext() is only used by Hash Aggregation, but it may be generally useful in the future. Discussion: https://postgr.es/m/412a3fbf306f84d8d78c4009e11791867e62b87c.camel@j-davis.com
* Support FETCH FIRST WITH TIESAlvaro Herrera2020-04-07
| | | | | | | | | | | | | | | | | | WITH TIES is an option to the FETCH FIRST N ROWS clause (the SQL standard's spelling of LIMIT), where you additionally get rows that compare equal to the last of those N rows by the columns in the mandatory ORDER BY clause. There was a proposal by Andrew Gierth to implement this functionality in a more powerful way that would yield more features, but the other patch had not been finished at this time, so we decided to use this one for now in the spirit of incremental development. Author: Surafel Temesgen <surafel3000@gmail.com> Reviewed-by: Álvaro Herrera <alvherre@alvh.no-ip.org> Reviewed-by: Tomas Vondra <tomas.vondra@2ndquadrant.com> Discussion: https://postgr.es/m/CALAY4q9ky7rD_A4vf=FVQvCGngm3LOes-ky0J6euMrg=_Se+ag@mail.gmail.com Discussion: https://postgr.es/m/87o8wvz253.fsf@news-spur.riddles.org.uk
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