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2020-03-04Extend ExecBuildAggTrans() to support a NULL pointer check.Jeff Davis
Optionally push a step to check for a NULL pointer to the pergroup state. This will be important for disk-based hash aggregation in combination with grouping sets. When memory limits are reached, a given tuple may find its per-group state for some grouping sets but not others. For the former, it advances the per-group state as normal; for the latter, it skips evaluation and the calling code will have to spill the tuple and reprocess it in a later batch. Add the NULL check as a separate expression step because in some common cases it's not needed. Discussion: https://postgr.es/m/20200221202212.ssb2qpmdgrnx52sj%40alap3.anarazel.de
2020-03-04Introduce macros for typalign and typstorage constants.Tom Lane
Our usual practice for "poor man's enum" catalog columns is to define macros for the possible values and use those, not literal constants, in C code. But for some reason lost in the mists of time, this was never done for typalign/attalign or typstorage/attstorage. It's never too late to make it better though, so let's do that. The reason I got interested in this right now is the need to duplicate some uses of the TYPSTORAGE constants in an upcoming ALTER TYPE patch. But in general, this sort of change aids greppability and readability, so it's a good idea even without any specific motivation. I may have missed a few places that could be converted, and it's even more likely that pending patches will re-introduce some hard-coded references. But that's not fatal --- there's no expectation that we'd actually change any of these values. We can clean up stragglers over time. Discussion: https://postgr.es/m/16457.1583189537@sss.pgh.pa.us
2020-03-02Represent command completion tags as structsAlvaro Herrera
The backend was using strings to represent command tags and doing string comparisons in multiple places, but that's slow and unhelpful. Create a new command list with a supporting structure to use instead; this is stored in a tag-list-file that can be tailored to specific purposes with a caller-definable C macro, similar to what we do for WAL resource managers. The first first such uses are a new CommandTag enum and a CommandTagBehavior struct. Replace numerous occurrences of char *completionTag with a QueryCompletion struct so that the code no longer stores information about completed queries in a cstring. Only at the last moment, in EndCommand(), does this get converted to a string. EventTriggerCacheItem no longer holds an array of palloc’d tag strings in sorted order, but rather just a Bitmapset over the CommandTags. Author: Mark Dilger, with unsolicited help from Álvaro Herrera Reviewed-by: John Naylor, Tom Lane Discussion: https://postgr.es/m/981A9DB4-3F0C-4DA5-88AD-CB9CFF4D6CAD@enterprisedb.com
2020-02-29Correctly re-use hash tables in buildSubPlanHash().Tom Lane
Commit 356687bd8 omitted to remove leftover code for destroying a hashed subplan's hash tables, with the result that the tables were always rebuilt not reused; this leads to severe memory leakage if a hashed subplan is re-executed enough times. Moreover, the code for reusing the hashnulls table had a typo that would have made it do the wrong thing if it were reached. Looking at the code coverage report shows severe under-coverage of the potential callers of ResetTupleHashTable, so add some test cases that exercise them. Andreas Karlsson and Tom Lane, per reports from Ranier Vilela and Justin Pryzby. Backpatch to v11, as the faulty commit was. Discussion: https://postgr.es/m/edb62547-c453-c35b-3ed6-a069e4d6b937@proxel.se Discussion: https://postgr.es/m/CAEudQAo=DCebm1RXtig9OH+QivpS97sMkikt0A9qHmMUs+g6ZA@mail.gmail.com Discussion: https://postgr.es/m/20200210032547.GA1412@telsasoft.com
2020-02-29Remove obsolete comment.Tom Lane
Noted while studying subplan hash issue.
2020-02-27Move src/backend/utils/hash/hashfn.c to src/commonRobert Haas
This also involves renaming src/include/utils/hashutils.h, which becomes src/include/common/hashfn.h. Perhaps an argument can be made for keeping the hashutils.h name, but it seemed more consistent to make it match the name of the file, and also more descriptive of what is actually going on here. Patch by me, reviewed by Suraj Kharage and Mark Dilger. Off-list advice on how not to break the Windows build from Davinder Singh and Amit Kapila. Discussion: http://postgr.es/m/CA+TgmoaRiG4TXND8QuM6JXFRkM_1wL2ZNhzaUKsuec9-4yrkgw@mail.gmail.com
2020-02-24expression eval: Reduce number of steps for agg transition invocations.Andres Freund
Do so by combining the various steps that are part of aggregate transition function invocation into one larger step. As some of the current steps are only necessary for some aggregates, have one variant of the aggregate transition step for each possible combination. To avoid further manual copies of code in the different transition step implementations, move most of the code into helper functions marked as "always inline". The benefit of this change is an increase in performance when aggregating lots of rows. This comes in part due to the reduced number of indirect jumps due to the reduced number of steps, and in part by reducing redundant setup code across steps. This mainly benefits interpreted execution, but the code generated by JIT is also improved a bit. As a nice side-effect it also ends up making the code a bit simpler. A small additional optimization is removing the need to set aggstate->curaggcontext before calling ExecAggInitGroup, choosing to instead passign curaggcontext as an argument. It was, in contrast to other aggregate related functions, only needed to fetch a memory context to copy the transition value into. Author: Andres Freund Discussion: https://postgr.es/m/20191023163849.sosqbfs5yenocez3@alap3.anarazel.de https://postgr.es/m/5c371df7cee903e8cd4c685f90c6c72086d3a2dc.camel@j-davis.com
2020-02-21Fixup for nodeAgg.c refactor.Jeff Davis
Commit 5b618e1f made an unintended behavior change.
2020-02-19Minor refactor of nodeAgg.c.Jeff Davis
* Separate calculation of hash value from the lookup. * Split build_hash_table() into two functions. * Change lookup_hash_entry() to return AggStatePerGroup. That's all the caller needed, anyway. These changes are to support the upcoming Disk-based Hash Aggregation work. Discussion: https://postgr.es/m/31f5ab871a3ad5a1a91a7a797651f20e77ac7ce3.camel%40j-davis.com
2020-02-18Remove duplicated words in commentsMichael Paquier
Author: Daniel Gustafsson Reviewed-by: Vik Fearing Discussion: https://postgr.es/m/EBC3BFEB-664C-4063-81ED-29F1227DB012@yesql.se
2020-02-17Optimize update of tables with generated columnsPeter Eisentraut
When updating a table row with generated columns, only recompute those generated columns whose base columns have changed in this update and keep the rest unchanged. This can result in a significant performance benefit. The required information was already kept in RangeTblEntry.extraUpdatedCols; we just have to make use of it. Reviewed-by: Pavel Stehule <pavel.stehule@gmail.com> Discussion: https://www.postgresql.org/message-id/flat/b05e781a-fa16-6b52-6738-761181204567@2ndquadrant.com
2020-02-10Change signature of TupleHashTableHash().Jeff Davis
Commit 4eaea3db introduced TupleHashTableHash(), but the signature didn't match the other exposed functions. Separate it into internal and external versions. The external version hides the details behind an API more consistent with the other external functions, and the internal version is still suitable for simplehash.
2020-02-07Fix bug in Tid scan.Fujii Masao
Commit 147e3722f7 changed Tid scan so that it calls table_beginscan() and uses the scan option for seq scan. This change caused two issues. (1) The change caused Tid scan to take a predicate lock on the entire relation in serializable transaction even when relation-level lock is not necessary. This could lead to an unexpected serialization error. (2) The change caused Tid scan to increment the number of seq_scan in pg_stat_*_tables views even though it's not seq scan. This could confuse the users. This commit adds the scan option for Tid scan and makes Tid scan use it, to avoid those issues. Back-patch to v12, where the bug was introduced. Author: Tatsuhito Kasahara Reviewed-by: Kyotaro Horiguchi, Masahiko Sawada, Fujii Masao Discussion: https://postgr.es/m/CAP0=ZVKy+gTbFmB6X_UW0pP3WaeJ-fkUWHoD-pExS=at3CY76g@mail.gmail.com
2020-02-06Introduce TupleHashTableHash() and LookupTupleHashEntryHash().Jeff Davis
Expose two new entry points: one for only calculating the hash value of a tuple, and another for looking up a hash entry when the hash value is already known. This will be useful for disk-based Hash Aggregation to avoid recomputing the hash value for the same tuple after saving and restoring it from disk. Discussion: https://postgr.es/m/37091115219dd522fd9ed67333ee8ed1b7e09443.camel%40j-davis.com
2020-02-06expression eval: Don't redundantly keep track of AggState.Andres Freund
It's already tracked via ExprState->parent, so we don't need to also include it in ExprEvalStep. When that code originally was written ExprState->parent didn't exist, but it since has been introduced in 6719b238e8f. Author: Andres Freund Discussion: https://postgr.es/m/20191023163849.sosqbfs5yenocez3@alap3.anarazel.de
2020-02-06expression eval, jit: Minor code cleanups.Andres Freund
This mostly consists of using C99 style for loops, moving variables into narrower scopes, and a smattering of other minor improvements. Done separately to make it easier to review patches with actual functional changes. Author: Andres Freund Discussion: https://postgr.es/m/20191023163849.sosqbfs5yenocez3@alap3.anarazel.de
2020-02-06Refactor hash_agg_entry_size().Jeff Davis
Consolidate the calculations for hash table size estimation. This will help with upcoming Hash Aggregation work that will add additional call sites.
2020-02-03Add missing break out seqscan loop in logical replicationAlvaro Herrera
When replica identity is FULL (an admittedly unusual case), the loop that searches for tuples in execReplication.c didn't stop scanning the table when once a matching tuple was found. Add the missing 'break'. Note slight behavior change: we now return the first matching tuple rather than the last one. They are supposed to be indistinguishable anyway, so this shouldn't matter. Author: Konstantin Knizhnik Discussion: https://postgr.es/m/379743f6-ae91-b866-f7a2-5624e6d2b0a4@postgrespro.ru
2020-01-30Clean up newlines following left parenthesesAlvaro Herrera
We used to strategically place newlines after some function call left parentheses to make pgindent move the argument list a few chars to the left, so that the whole line would fit under 80 chars. However, pgindent no longer does that, so the newlines just made the code vertically longer for no reason. Remove those newlines, and reflow some of those lines for some extra naturality. Reviewed-by: Michael Paquier, Tom Lane Discussion: https://postgr.es/m/20200129200401.GA6303@alvherre.pgsql
2020-01-28Fix dangling pointer in EvalPlanQual machinery.Tom Lane
EvalPlanQualStart() supposed that it could re-use the relsubs_rowmark and relsubs_done arrays from a prior instantiation. But since they are allocated in the es_query_cxt of the recheckestate, that's just wrong; EvalPlanQualEnd() will blow away that storage. Therefore we were using storage that could have been reallocated to something else, causing all sorts of havoc. I think this was modeled on the old code's handling of es_epqTupleSlot, but since the code was anyway clearing the arrays at re-use, there's clearly no expectation of importing any outside state. So it's just a dubious savings of a couple of pallocs, which is negligible compared to setting up a new planstate tree. Therefore, just allocate the arrays always. (I moved the allocations slightly for readability.) In principle this bug could cause a problem whenever EPQ rechecks are needed in more than one target table of a ModifyTable plan node. In practice it seems not quite so easy to trigger as that; I couldn't readily duplicate a crash with a partitioned target table, for instance. That's probably down to incidental choices about when to free or reallocate stuff. The added isolation test case does seem to reliably show an assertion failure, though. Per report from Oleksii Kliukin. Back-patch to v12 where the bug was introduced (evidently by commit 3fb307bc4). Discussion: https://postgr.es/m/EEF05F66-2871-4786-992B-5F45C92FEE2E@hintbits.com
2020-01-28Added relation name in error messages for constraint checks.Amit Kapila
This gives more information to the user about the error and it makes such messages consistent with the other similar messages in the code. Reported-by: Simon Riggs Author: Mahendra Singh and Simon Riggs Reviewed-by: Beena Emerson and Amit Kapila Discussion: https://postgr.es/m/CANP8+j+7YUvQvGxTrCiw77R23enMJ7DFmyA3buR+fa2pKs4XhA@mail.gmail.com
2020-01-27Avoid unnecessary shm writes in Parallel Hash Join.Thomas Munro
Currently, Parallel Hash Join cannot be used for full/right joins, so there is no point in setting the match flag. It turns out that the cache coherence traffic generated by those writes slows down large systems running many-core joins, so let's stop doing that. In future, if we need to use match bits in parallel joins, we might want to consider setting them only if not already set. Back-patch to 11, where Parallel Hash Join arrived. Reported-by: Deng, Gang Discussion: https://postgr.es/m/0F44E799048C4849BAE4B91012DB910462E9897A%40SHSMSX103.ccr.corp.intel.com
2020-01-20Fix edge case leading to agg transitions skipping ExecAggTransReparent() calls.Andres Freund
The code checking whether an aggregate transition value needs to be reparented into the current context has always only compared the transition return value with the previous transition value by datum, i.e. without regard for NULLness. This normally works, because when the transition function returns NULL (via fcinfo->isnull), it'll return a value that won't be the same as its input value. But there's no hard requirement that that's the case. And it turns out, it's possible to hit this case (see discussion or reproducers), leading to a non-null transition value not being reparented, followed by a crash caused by that. Instead of adding another comparison of NULLness, instead have ExecAggTransReparent() ensure that pergroup->transValue ends up as 0 when the new transition value is NULL. That avoids having to add an additional branch to the much more common cases of the transition function returning the old transition value (which is a pointer in this case), and when the new value is different, but not NULL. In branches since 69c3936a149, also deduplicate the reparenting code between the expression evaluation based transitions, and the path for ordered aggregates. Reported-By: Teodor Sigaev, Nikita Glukhov Author: Andres Freund Discussion: https://postgr.es/m/bd34e930-cfec-ea9b-3827-a8bc50891393@sigaev.ru Backpatch: 9.4-, this issue has existed since at least 7.4
2020-01-17Repair more failures with SubPlans in multi-row VALUES lists.Tom Lane
Commit 9b63c13f0 turns out to have been fundamentally misguided: the parent node's subPlan list is by no means the only way in which a child SubPlan node can be hooked into the outer execution state. As shown in bug #16213 from Matt Jibson, we can also get short-lived tuple table slots added to the outer es_tupleTable list. At this point I have little faith that there aren't other possible connections as well; the long time it took to notice this problem shows that this isn't a heavily-exercised situation. Therefore, revert that fix, returning to the coding that passed a NULL parent plan pointer down to the transiently-built subexpressions. That gives us a pretty good guarantee that they won't hook into the outer executor state in any way. But then we need some other solution to make SubPlans work. Adopt the solution speculated about in the previous commit's log message: do expression initialization at plan startup for just those VALUES rows containing SubPlans, abandoning the goal of reclaiming memory intra-query for those rows. In practice it seems unlikely that queries containing a vast number of VALUES rows would be using SubPlans in them, so this should not give up much. (BTW, this test case also refutes my claim in connection with the prior commit that the issue only arises with use of LATERAL. That was just wrong: some variants of SubLink always produce SubPlans.) As with previous patch, back-patch to all supported branches. Discussion: https://postgr.es/m/16213-871ac3bc208ecf23@postgresql.org
2020-01-16Fix problems with "read only query" checks, and refactor the code.Robert Haas
Previously, check_xact_readonly() was responsible for determining which types of queries could not be run in a read-only transaction, standard_ProcessUtility() was responsibility for prohibiting things which were allowed in read only transactions but not in recovery, and utility commands were basically prohibited in bulk in parallel mode by calls to CommandIsReadOnly() in functions.c and spi.c. This situation was confusing and error-prone. Accordingly, move all the checks to a new function ClassifyUtilityCommandAsReadOnly(), which determines the degree to which a given statement is read only. In the old code, check_xact_readonly() inadvertently failed to handle several statement types that actually should have been prohibited, specifically T_CreatePolicyStmt, T_AlterPolicyStmt, T_CreateAmStmt, T_CreateStatsStmt, T_AlterStatsStmt, and T_AlterCollationStmt. As a result, thes statements were erroneously allowed in read only transactions, parallel queries, and standby operation. Generally, they would fail anyway due to some lower-level error check, but we shouldn't rely on that. In the new code structure, future omissions of this type should cause ClassifyUtilityCommandAsReadOnly() to complain about an unrecognized node type. As a fringe benefit, this means we can allow certain types of utility commands in parallel mode, where it's safe to do so. This allows ALTER SYSTEM, CALL, DO, CHECKPOINT, COPY FROM, EXPLAIN, and SHOW. It might be possible to allow additional commands with more work and thought. Along the way, document the thinking process behind the current set of checks, as per discussion especially with Peter Eisentraut. There is some interest in revising some of these rules, but that seems like a job for another patch. Patch by me, reviewed by Tom Lane, Stephen Frost, and Peter Eisentraut. Discussion: http://postgr.es/m/CA+TgmoZ_rLqJt5sYkvh+JpQnfX0Y+B2R+qfi820xNih6x-FQOQ@mail.gmail.com
2020-01-14Make rewriter prevent auto-updates on views with conditional INSTEAD rules.Dean Rasheed
A view with conditional INSTEAD rules and no unconditional INSTEAD rules or INSTEAD OF triggers is not auto-updatable. Previously we relied on a check in the executor to catch this, but that's problematic since the planner may fail to properly handle such a query and thus return a particularly unhelpful error to the user, before reaching the executor check. Instead, trap this in the rewriter and report the correct error there. Doing so also allows us to include more useful error detail than the executor check can provide. This doesn't change the existing behaviour of updatable views; it merely ensures that useful error messages are reported when a view isn't updatable. Per report from Pengzhou Tang, though not adopting that suggested fix. Back-patch to all supported branches. Discussion: https://postgr.es/m/CAG4reAQn+4xB6xHJqWdtE0ve_WqJkdyCV4P=trYr4Kn8_3_PEA@mail.gmail.com
2020-01-08Improve the handling of result type coercions in SQL functions.Tom Lane
Use the parser's standard type coercion machinery to convert the output column(s) of a SQL function's final SELECT or RETURNING to the type(s) they should have according to the function's declared result type. We'll allow any case where an assignment-level coercion is available. Previously, we failed unless the required coercion was a binary-compatible one (and the documentation ignored this, falsely claiming that the types must match exactly). Notably, the coercion now accounts for typmods, so that cases where a SQL function is declared to return a composite type whose columns are typmod-constrained now behave as one would expect. Arguably this aspect is a bug fix, but the overall behavioral change here seems too large to consider back-patching. A nice side-effect is that functions can now be inlined in a few cases where we previously failed to do so because of type mismatches. Discussion: https://postgr.es/m/18929.1574895430@sss.pgh.pa.us
2020-01-01Update copyrights for 2020Bruce Momjian
Backpatch-through: update all files in master, backpatch legal files through 9.4
2019-12-27Revert "Rename files and headers related to index AM"Michael Paquier
This follows multiple complains from Peter Geoghegan, Andres Freund and Alvaro Herrera that this issue ought to be dug more before actually happening, if it happens. Discussion: https://postgr.es/m/20191226144606.GA5659@alvherre.pgsql
2019-12-25Load relcache entries' partitioning data on-demand, not immediately.Tom Lane
Formerly the rd_partkey and rd_partdesc data structures were always populated immediately when a relcache entry was built or rebuilt. This patch changes things so that they are populated only when they are first requested. (Hence, callers *must* now always use RelationGetPartitionKey or RelationGetPartitionDesc; just fetching the pointer directly is no longer acceptable.) This seems to have some performance benefits, but the main reason to do it is that it eliminates a recursive-reload failure that occurs if the partkey or partdesc expressions contain any references to the relation's rowtype (as discovered by Amit Langote). In retrospect, since loading these data structures might result in execution of nearly-arbitrary code via eval_const_expressions, it was a dumb idea to require that to happen during relcache entry rebuild. Also, fix things so that old copies of a relcache partition descriptor will be dropped when the cache entry's refcount goes to zero. In the previous coding it was possible for such copies to survive for the lifetime of the session, as I'd complained of in a previous discussion. (This management technique still isn't perfect, but it's better than before.) Improve the commentary explaining how that works and why it's safe to hand out direct pointers to these relcache substructures. In passing, improve RelationBuildPartitionDesc by using the same memory-context-parent-swap approach used by RelationBuildPartitionKey, thereby making it less dependent on strong assumptions about what partition_bounds_copy does. Avoid doing get_rel_relkind in the critical section, too. Patch by Amit Langote and Tom Lane; Robert Haas deserves some credit for prior work in the area, too. Although this is a pre-existing problem, no back-patch: the patch seems too invasive to be safe to back-patch, and the bug it fixes is a corner case that seems relatively unlikely to cause problems in the field. Discussion: https://postgr.es/m/CA+HiwqFUzjfj9HEsJtYWcr1SgQ_=iCAvQ=O2Sx6aQxoDu4OiHw@mail.gmail.com Discussion: https://postgr.es/m/CA+TgmoY3bRmGB6-DUnoVy5fJoreiBJ43rwMrQRCdPXuKt4Ykaw@mail.gmail.com
2019-12-25Rename files and headers related to index AMMichael Paquier
The following renaming is done so as source files related to index access methods are more consistent with table access methods (the original names used for index AMs ware too generic, and could be confused as including features related to table AMs): - amapi.h -> indexam.h. - amapi.c -> indexamapi.c. Here we have an equivalent with backend/access/table/tableamapi.c. - amvalidate.c -> indexamvalidate.c. - amvalidate.h -> indexamvalidate.h. - genam.c -> indexgenam.c. - genam.h -> indexgenam.h. This has been discussed during the development of v12 when table AM was worked on, but the renaming never happened. Author: Michael Paquier Reviewed-by: Fabien Coelho, Julien Rouhaud Discussion: https://postgr.es/m/20191223053434.GF34339@paquier.xyz
2019-12-24Avoid splitting C string literals with \-newlineAlvaro Herrera
Using \ is unnecessary and ugly, so remove that. While at it, stitch the literals back into a single line: we've long discouraged splitting error message literals even when they go past the 80 chars line limit, to improve greppability. Leave contrib/tablefunc alone. Discussion: https://postgr.es/m/20191223195156.GA12271@alvherre.pgsql
2019-12-24Rotate instead of shifting hash join batch number.Thomas Munro
Our algorithm for choosing batch numbers turned out not to work effectively for multi-billion key inner relations. We would use more hash bits than we have, and effectively concentrate all tuples into a smaller number of batches than we intended. While ideally we should switch to wider hashes, for now, change the algorithm to one that effectively gives up bits from the bucket number when we don't have enough bits. That means we'll finish up with longer bucket chains than would be ideal, but that's better than having batches that don't fit in work_mem and can't be divided. Batch-patch to all supported releases. Author: Thomas Munro Reviewed-by: Tom Lane, thanks also to Tomas Vondra, Alvaro Herrera, Andres Freund for testing and discussion Reported-by: James Coleman Discussion: https://postgr.es/m/16104-dc11ed911f1ab9df%40postgresql.org
2019-12-18Refactor attribute mappings used in logical tuple conversionMichael Paquier
Tuple conversion support in tupconvert.c is able to convert rowtypes between two relations, inner and outer, which are logically equivalent but have a different ordering or even dropped columns (used mainly for inheritance tree and partitions). This makes use of attribute mappings, which are simple arrays made of AttrNumber elements with a length matching the number of attributes of the outer relation. The length of the attribute mapping has been treated as completely independent of the mapping itself until now, making it easy to pass down an incorrect mapping length. This commit refactors the code related to attribute mappings and moves it into an independent facility called attmap.c, extracted from tupconvert.c. This merges the attribute mapping with its length, avoiding to try to guess what is the length of a mapping to use as this is computed once, when the map is built. This will avoid mistakes like what has been fixed in dc816e58, which has used an incorrect mapping length by matching it with the number of attributes of an inner relation (a child partition) instead of an outer relation (a partitioned table). Author: Michael Paquier Reviewed-by: Amit Langote Discussion: https://postgr.es/m/20191121042556.GD153437@paquier.xyz
2019-12-17Remove redundant not-null testBruce Momjian
Reported-by: Ranier Vilela Discussion: https://postgr.es/m/MN2PR18MB2927E73FADCA8967B2302469E3490@MN2PR18MB2927.namprd18.prod.outlook.com Author: Ranier Vilela Backpatch-through: master
2019-12-11Allow executor startup pruning to prune all child nodes.Tom Lane
Previously, if the startup pruning logic proved that all child nodes of an Append or MergeAppend could be pruned, we still kept one, just to keep EXPLAIN from failing. The previous commit removed the ruleutils.c limitation that required this kluge, so drop it. That results in less-confusing EXPLAIN output, as per a complaint from Yuzuko Hosoya. David Rowley Discussion: https://postgr.es/m/001001d4f44b$2a2cca50$7e865ef0$@lab.ntt.co.jp
2019-12-11Further adjust EXPLAIN's choices of table alias names.Tom Lane
This patch causes EXPLAIN to always assign a separate table alias to the parent RTE of an append relation (inheritance set); before, such RTEs were ignored if not actually scanned by the plan. Since the child RTEs now always have that same alias to start with (cf. commit 55a1954da), the net effect is that the parent RTE usually gets the alias used or implied by the query text, and the children all get that alias with "_N" appended. (The exception to "usually" is if there are duplicate aliases in different subtrees of the original query; then some of those original RTEs will also have "_N" appended.) This results in more uniform output for partitioned-table plans than we had before: the partitioned table itself gets the original alias, and all child tables have aliases with "_N", rather than the previous behavior where one of the children would get an alias without "_N". The reason for giving the parent RTE an alias, even if it isn't scanned by the plan, is that we now use the parent's alias to qualify Vars that refer to an appendrel output column and appear above the Append or MergeAppend that computes the appendrel. But below the append, Vars refer to some one of the child relations, and are displayed that way. This seems clearer than the old behavior where a Var that could carry values from any child relation was displayed as if it referred to only one of them. While at it, change ruleutils.c so that the code paths used by EXPLAIN deal in Plan trees not PlanState trees. This effectively reverts a decision made in commit 1cc29fe7c, which seemed like a good idea at the time to make ruleutils.c consistent with explain.c. However, it's problematic because we'd really like to allow executor startup pruning to remove all the children of an append node when possible, leaving no child PlanState to resolve Vars against. (That's not done here, but will be in the next patch.) This requires different handling of subplans and initplans than before, but is otherwise a pretty straightforward change. Discussion: https://postgr.es/m/001001d4f44b$2a2cca50$7e865ef0$@lab.ntt.co.jp
2019-12-06Fix comments in execGrouping.cJeff Davis
Commit 5dfc1981 missed updating some comments. Also, fix a comment typo found in passing. Author: Jeff Davis Discussion: https://postgr.es/m/9723131d247b919f94699152647fa87ee0bc02c2.camel%40j-davis.com
2019-12-04Fix whitespace.Etsuro Fujita
2019-11-28Remove useless "return;" linesAlvaro Herrera
Discussion: https://postgr.es/m/20191128144653.GA27883@alvherre.pgsql
2019-11-26Don't shut down Gather[Merge] early under Limit.Amit Kapila
Revert part of commit 19df1702f5. Early shutdown was added by that commit so that we could collect statistics from workers, but unfortunately, it interacted badly with rescans. The problem is that we ended up destroying the parallel context which is required for rescans. This leads to rescans of a Limit node over a Gather node to produce unpredictable results as it tries to access destroyed parallel context. By reverting the early shutdown code, we might lose statistics in some cases of Limit over Gather [Merge], but that will require further study to fix. Reported-by: Jerry Sievers Diagnosed-by: Thomas Munro Author: Amit Kapila, testcase by Vignesh C Backpatch-through: 9.6 Discussion: https://postgr.es/m/87ims2amh6.fsf@jsievers.enova.com
2019-11-16Always call ExecShutdownNode() if appropriate.Thomas Munro
Call ExecShutdownNode() after ExecutePlan()'s loop, rather than at each break. We had forgotten to do that in one case. The omission caused intermittent "temporary file leak" warnings from multi-batch parallel hash joins with a LIMIT clause. Back-patch to 11. Though the problem exists in theory in earlier parallel query releases, nothing really depended on it. Author: Kyotaro Horiguchi Reviewed-by: Thomas Munro, Amit Kapila Discussion: https://postgr.es/m/20191111.212418.2222262873417235945.horikyota.ntt%40gmail.com
2019-11-12Make the order of the header file includes consistent in backend modules.Amit Kapila
Similar to commits 7e735035f2 and dddf4cdc33, this commit makes the order of header file inclusion consistent for backend modules. In the passing, removed a couple of duplicate inclusions. Author: Vignesh C Reviewed-by: Kuntal Ghosh and Amit Kapila Discussion: https://postgr.es/m/CALDaNm2Sznv8RR6Ex-iJO6xAdsxgWhCoETkaYX=+9DW3q0QCfA@mail.gmail.com
2019-11-07Add reusable routine for making arrays unique.Thomas Munro
Introduce qunique() and qunique_arg(), which can be used after qsort() and qsort_arg() respectively to remove duplicate values. Use it where appropriate. Author: Thomas Munro Reviewed-by: Tom Lane (in an earlier version) Discussion: https://postgr.es/m/CAEepm%3D2vmFTNpAmwbGGD2WaryM6T3hSDVKQPfUwjdD_5XY6vAA%40mail.gmail.com
2019-11-06Minor code review for tuple slot rewrite.Tom Lane
Avoid creating transiently-inconsistent slot states where possible, by not setting TTS_FLAG_SHOULDFREE until after the slot actually has a free'able tuple pointer, and by making sure that we reset tts_nvalid and related derived state before we replace the tuple contents. This would only matter if something were to examine the slot after we'd suffered some kind of error (e.g. out of memory) while manipulating the slot. We typically don't do that, so these changes might just be cosmetic --- but even if so, it seems like good future-proofing. Also remove some redundant Asserts, and add a couple for consistency. Back-patch to v12 where all this code was rewritten. Discussion: https://postgr.es/m/16095-c3ff2e5283b8dba5@postgresql.org
2019-11-05Split all OBJS style lines in makefiles into one-line-per-entry style.Andres Freund
When maintaining or merging patches, one of the most common sources for conflicts are the list of objects in makefiles. Especially when the split across lines has been changed on both sides, which is somewhat common due to attempting to stay below 80 columns, those conflicts are unnecessarily laborious to resolve. By splitting, and alphabetically sorting, OBJS style lines into one object per line, conflicts should be less frequent, and easier to resolve when they still occur. Author: Andres Freund Discussion: https://postgr.es/m/20191029200901.vww4idgcxv74cwes@alap3.anarazel.de
2019-10-04Rename some toasting functions based on whether they are heap-specific.Robert Haas
The old names for the attribute-detoasting functions names included the word "heap," which seems outdated now that the heap is only one of potentially many table access methods. On the other hand, toast_insert_or_update and toast_delete are heap-specific, so rename them by adding "heap_" as a prefix. Not all of the work of making the TOAST system fully accessible to AMs other than the heap is done yet, but there seems to be little harm in getting this renaming out of the way now. Commit 8b94dab06617ef80a0901ab103ebd8754427ef5a already divided up the functions among various files partially according to whether it was intended that they should be heap-specific or AM-agnostic, so this is just clarifying the division contemplated by that commit. Patch by me, reviewed and tested by Prabhat Sabu, Thomas Munro, Andres Freund, and Álvaro Herrera. Discussion: http://postgr.es/m/CA+TgmoZv-=2iWM4jcw5ZhJeL18HF96+W1yJeYrnGMYdkFFnEpQ@mail.gmail.com
2019-09-30Don't generate EEOP_*_FETCHSOME operations for slots know to be virtual.Andres Freund
That avoids unnecessary work during both interpreted execution, and JIT compiled expression evaluation. Both benefit from fewer expression steps needing be processed, and for interpreted execution there now is a fastpath dedicated to just fetching a value from a virtual slot. That's e.g. beneficial for hashjoins over nodes that perform projections, as the hashed columns are currently fetched individually. Author: Soumyadeep Chakraborty, Andres Freund Discussion: https://postgr.es/m/CAE-ML+9OKSN71+mHtfMD-L24oDp8dGTfaVjDU6U+j+FNAW5kRQ@mail.gmail.com
2019-09-30Reduce code duplication for ExecJust*Var operations.Andres Freund
This is mainly in preparation for adding further fastpath evaluation routines. Also reorder ExecJust*Var functions to be consistent with the order in which they're used. Author: Andres Freund Discussion: https://postgr.es/m/CAE-ML+9OKSN71+mHtfMD-L24oDp8dGTfaVjDU6U+j+FNAW5kRQ@mail.gmail.com
2019-09-29jit: Re-allow JIT compilation of execGrouping.c hashtable comparisons.Andres Freund
In the course of 5567d12ce03, 356687bd8 and 317ffdfeaac, I changed BuildTupleHashTable[Ext]'s call to ExecBuildGroupingEqual to not pass in the parent node, but NULL. Which in turn prevents the tuple equality comparator from being JIT compiled. While that fixes bug #15486, it is not actually necessary after all of the above commits, as we don't re-build the comparator when using the new BuildTupleHashTableExt() interface (as the content of the hashtable are reset, but the TupleHashTable itself is not). Therefore re-allow jit compilation for callers that use BuildTupleHashTableExt with a separate context for "metadata" and content. As in the previous commit, there's ongoing work to make this easier to test to prevent such regressions in the future, but that infrastructure is not going to be backpatchable. The performance impact of not JIT compiling hashtable equality comparators can be substantial e.g. for aggregation queries that aggregate a lot of input rows to few output rows (when there are a lot of output groups, there will be fewer comparisons). Author: Andres Freund Discussion: https://postgr.es/m/20190927072053.njf6prdl3vb7y7qb@alap3.anarazel.de Backpatch: 11, just as 5567d12ce03