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2023-04-13De-Revert "Add support for Kerberos credential delegation"Stephen Frost
This reverts commit 3d03b24c3 (Revert Add support for Kerberos credential delegation) which was committed on the grounds of concern about portability, but on further review and discussion, it's clear that we are better off explicitly requiring MIT Kerberos as that appears to be the only GSSAPI library currently that's under proper maintenance and ongoing development. The API used for storing credentials was added to MIT Kerberos over a decade ago while for the other libraries which appear to be mainly based on Heimdal, which exists explicitly to be a re-implementation of MIT Kerberos, the API never made it to a released version (even though it was added to the Heimdal git repo over 5 years ago..). This post-feature-freeze change was approved by the RMT. Discussion: https://postgr.es/m/ZDDO6jaESKaBgej0%40tamriel.snowman.net
2023-04-08Revert "Add support for Kerberos credential delegation"Stephen Frost
This reverts commit 3d4fa227bce4294ce1cc214b4a9d3b7caa3f0454. Per discussion and buildfarm, this depends on APIs that seem to not be available on at least one platform (NetBSD). Should be certainly possible to rework to be optional on that platform if necessary but bit late for that at this point. Discussion: https://postgr.es/m/[email protected]
2023-04-08Add support for Kerberos credential delegationStephen Frost
Support GSSAPI/Kerberos credentials being delegated to the server by a client. With this, a user authenticating to PostgreSQL using Kerberos (GSSAPI) credentials can choose to delegate their credentials to the PostgreSQL server (which can choose to accept them, or not), allowing the server to then use those delegated credentials to connect to another service, such as with postgres_fdw or dblink or theoretically any other service which is able to be authenticated using Kerberos. Both postgres_fdw and dblink are changed to allow non-superuser password-less connections but only when GSSAPI credentials have been delegated to the server by the client and GSSAPI is used to authenticate to the remote system. Authors: Stephen Frost, Peifeng Qiu Reviewed-By: David Christensen Discussion: https://postgr.es/m/CO1PR05MB8023CC2CB575E0FAAD7DF4F8A8E29@CO1PR05MB8023.namprd05.prod.outlook.com
2023-04-06postgres_fdw: Add support for parallel abort.Etsuro Fujita
postgres_fdw aborts remote (sub)transactions opened on remote server(s) in a local (sub)transaction one by one when the local (sub)transaction aborts. This patch allows it to abort the remote (sub)transactions in parallel to improve performance. This is enabled by the server option "parallel_abort". The default is false. Etsuro Fujita, reviewed by David Zhang. Discussion: http://postgr.es/m/CAPmGK15FuPVGx3TGHKShsbPKKtF1y58-ZLcKoxfN-nqLj1dZ%3Dg%40mail.gmail.com
2023-02-28Drop test view when done with it.Tom Lane
The view just added by commit 53fe7e6cb decompiles differently in v15 than HEAD (presumably as a consequence of 47bb9db75). That causes failures in cross-version upgrade testing. We could teach AdjustUpgrade.pm to compensate for that, but it seems less painful to just drop the view after we're done with it. Per buildfarm.
2023-02-27Harden postgres_fdw tests against unexpected cache flushes.Tom Lane
postgres_fdw will close its remote session if an sinval cache reset occurs, since it's possible that that means some FDW parameters changed. We had two tests that were trying to ensure that the session remains alive by setting debug_discard_caches = 0; but that's not sufficient. Even though the tests seem stable enough in the buildfarm, they flap a lot under CI. In the first test, which is checking the ability to recover from a lost connection, we can stabilize the results by just not caring whether pg_terminate_backend() finds a victim backend. If a reset did happen, there won't be a session to terminate anymore, but the test can proceed anyway. (Arguably, we are then not testing the unintentional-disconnect case, but as long as that scenario is exercised in most runs I think it's fine; testing the reset-driven case is of value too.) In the second test, which is trying to verify the application_name displayed in pg_stat_activity by a remote session, we had a race condition in that the remote session might go away before we can fetch its pg_stat_activity entry. We can close that race and make the test more certainly test what it intends to by arranging things so that the remote session itself fetches its pg_stat_activity entry (based on PID rather than a somewhat-circular assumption about the application name). Both tests now demonstrably pass under debug_discard_caches = 1, so we can remove that hack. Back-patch into relevant back branches. Discussion: https://postgr.es/m/[email protected]
2023-01-30Invent "join domains" to replace the below_outer_join hack.Tom Lane
EquivalenceClasses are now understood as applying within a "join domain", which is a set of inner-joined relations (possibly underneath an outer join). We no longer need to treat an EC from below an outer join as a second-class citizen. I have hopes of eventually being able to treat outer-join clauses via EquivalenceClasses, by means of only applying deductions within the EC's join domain. There are still problems in the way of that, though, so for now the reconsider_outer_join_clause logic is still here. I haven't been able to get rid of RestrictInfo.is_pushed_down either, but I wonder if that could be recast using JoinDomains. I had to hack one test case in postgres_fdw.sql to make it still test what it was meant to, because postgres_fdw is inconsistent about how it deals with quals containing non-shippable expressions; see https://postgr.es/m/[email protected]. That should be improved, but I don't think it's within the scope of this patch series. Patch by me; thanks to Richard Guo for review. Discussion: https://postgr.es/m/[email protected]
2022-12-30Sample postgres_fdw tables remotely during ANALYZETomas Vondra
When collecting ANALYZE sample on foreign tables, postgres_fdw fetched all rows and performed the sampling locally. For large tables this means transferring and immediately discarding large amounts of data. This commit allows the sampling to be performed on the remote server, transferring only the much smaller sample. The sampling is performed using the built-in TABLESAMPLE methods (system, bernoulli) or random() function, depending on the remote server version. Remote sampling can be enabled by analyze_sampling on the foreign server and/or foreign table, with supported values 'off', 'auto', 'system', 'bernoulli' and 'random'. The default value is 'auto' which uses either 'bernoulli' (TABLESAMPLE method) or 'random' (for remote servers without TABLESAMPLE support).
2022-12-23Fix bug in translate_col_privs_multilevelDavid Rowley
Fix incorrect code which was trying to convert a Bitmapset of columns at the attnums according to a parent table and transform them into the equivalent Bitmapset with same attnums according to the given child table. This code is new as of a61b1f748 and was failing to do the correct translation when there was an intermediate parent table between 'rel' and 'top_parent_rel'. Reported-by: Ranier Vilela Author: Richard Guo, Amit Langote Discussion: https://postgr.es/m/CAEudQArohfB_Gy%2BhcH2-bANUkxgjJiP%3DABq01_LgTNTbcNijag%40mail.gmail.com
2022-12-20Allow batching of inserts during cross-partition updates.Etsuro Fujita
Commit 927f453a9 disallowed batching added by commit b663a4136 to be used for the inserts performed as part of cross-partition updates of partitioned tables, mainly because the previous code in nodeModifyTable.c couldn't handle pending inserts into foreign-table partitions that are also UPDATE target partitions. But we don't have such a limitation anymore (cf. commit ffbb7e65a), so let's allow for this by removing from execPartition.c the restriction added by commit 927f453a9 that batching is only allowed if the query command type is CMD_INSERT. In postgres_fdw, since commit 86dc90056 changed it to effectively disable cross-partition updates in the case where a foreign-table partition chosen to insert rows into is also an UPDATE target partition, allow batching in the case where a foreign-table partition chosen to do so is *not* also an UPDATE target partition. This is enabled by the "batch_size" option added by commit b663a4136, which is disabled by default. This patch also adjusts the test case added by commit 927f453a9 to confirm that the inserts performed as part of a cross-partition update of a partitioned table indeed uses batching. Amit Langote, reviewed and/or tested by Georgios Kokolatos, Zhihong Yu, Bharath Rupireddy, Hou Zhijie, Vignesh C, and me. Discussion: http://postgr.es/m/CA%2BHiwqH1Lz1yJmPs%3DaD-pzd_HLLynLHvq5iYeT9mB0bBV7oJ6w%40mail.gmail.com
2022-12-16Remove pessimistic cost penalization from Incremental SortDavid Rowley
When incremental sorts were added in v13 a 1.5x pessimism factor was added to the cost modal. Seemingly this was done because the cost modal only has an estimate of the total number of input rows and the number of presorted groups. It assumes that the input rows will be evenly distributed throughout the presorted groups. The 1.5x pessimism factor was added to slightly reduce the likelihood of incremental sorts being used in the hope to avoid performance regressions where an incremental sort plan was picked and turned out slower due to a large skew in the number of rows in the presorted groups. An additional quirk with the path generation code meant that we could consider both a sort and an incremental sort on paths with presorted keys. This meant that with the pessimism factor, it was possible that we opted to perform a sort rather than an incremental sort when the given path had presorted keys. Here we remove the 1.5x pessimism factor to allow incremental sorts to have a fairer chance at being chosen against a full sort. Previously we would generally create a sort path on the cheapest input path (if that wasn't sorted already) and incremental sort paths on any path which had presorted keys. This meant that if the cheapest input path wasn't completely sorted but happened to have presorted keys, we would create a full sort path *and* an incremental sort path on that input path. Here we change this logic so that if there are presorted keys, we only create an incremental sort path, and create sort paths only when a full sort is required. Both the removal of the cost pessimism factor and the changes made to the path generation make it more likely that incremental sorts will now be chosen. That, of course, as with teaching the planner any new tricks, means an increased likelihood that the planner will perform an incremental sort when it's not the best method. Our standard escape hatch for these cases is an enable_* GUC. enable_incremental_sort already exists for this. This came out of a report by Pavel Luzanov where he mentioned that the master branch was choosing to perform a Seq Scan -> Sort -> Group Aggregate for his query with an ORDER BY aggregate function. The v15 plan for his query performed an Index Scan -> Group Aggregate, of course, the aggregate performed the final sort internally in nodeAgg.c for the aggregate's ORDER BY. The ideal plan would have been to use the index, which provided partially sorted input then use an incremental sort to provide the aggregate with the sorted input. This was not being chosen due to the pessimism in the incremental sort cost modal, so here we remove that and rationalize the path generation so that sort and incremental sort plans don't have to needlessly compete. We assume that it's senseless to ever use a full sort on a given input path where an incremental sort can be performed. Reported-by: Pavel Luzanov Reviewed-by: Richard Guo Discussion: https://postgr.es/m/9f61ddbf-2989-1536-b31e-6459370a6baa%40postgrespro.ru
2022-11-25Fix handling of pending inserts in nodeModifyTable.c.Etsuro Fujita
Commit b663a4136, which allowed FDWs to INSERT rows in bulk, added to nodeModifyTable.c code to flush pending inserts to the foreign-table result relation(s) before completing processing of the ModifyTable node, but the code failed to take into account the case where the INSERT query has modifying CTEs, leading to incorrect results. Also, that commit failed to flush pending inserts before firing BEFORE ROW triggers so that rows are visible to such triggers. In that commit we scanned through EState's es_tuple_routing_result_relations or es_opened_result_relations list to find the foreign-table result relations to which pending inserts are flushed, but that would be inefficient in some cases. So to fix, 1) add a List member to EState to record the insert-pending result relations, and 2) modify nodeModifyTable.c so that it adds the foreign-table result relation to the list in ExecInsert() if appropriate, and flushes pending inserts properly using the list where needed. While here, fix a copy-and-pasteo in a comment in ExecBatchInsert(), which was added by that commit. Back-patch to v14 where that commit appeared. Discussion: https://postgr.es/m/CAPmGK16qutyCmyJJzgQOhfBq%3DNoGDqTB6O0QBZTihrbqre%2BoxA%40mail.gmail.com
2022-10-15Disallow MERGE cleanly for foreign partitionsAlvaro Herrera
While directly targetting a foreign table with MERGE was already expressly forbidden, we failed to catch the case of a partitioned table that has a foreign table as a partition; and the result if you try is an incomprehensible error. Fix that by adding a specific check. Backpatch to 15. Reported-by: Tatsuhiro Nakamori <[email protected]> Discussion: https://postgr.es/m/[email protected]
2022-10-13Allow batch insertion during COPY into a foreign table.Etsuro Fujita
Commit 3d956d956 allowed the COPY, but it's done by inserting individual rows to the foreign table, so it can be inefficient due to the overhead caused by each round-trip to the foreign server. To improve performance of the COPY in such a case, this patch allows batch insertion, by extending the multi-insert machinery in CopyFrom() to the foreign-table case so that we insert multiple rows to the foreign table at once using the FDW callback routine added by commit b663a4136. This patch also allows this for postgres_fdw. It is enabled by the "batch_size" option added by commit b663a4136, which is disabled by default. When doing batch insertion, we update progress of the COPY command after performing the FDW callback routine, to count rows not suppressed by the FDW as well as a BEFORE ROW INSERT trigger. For consistency, this patch changes the timing of updating it for plain tables: previously, we updated it immediately after adding each row to the multi-insert buffer, but we do so only after writing the rows stored in the buffer out to the table using table_multi_insert(), which I think would be consistent even with non-batching mode, because in that mode we update it after writing each row out to the table using table_tuple_insert(). Andrey Lepikhov, heavily revised by me, with review from Ian Barwick, Andrey Lepikhov, and Zhihong Yu. Discussion: https://postgr.es/m/bc489202-9855-7550-d64c-ad2d83c24867%40postgrespro.ru
2022-09-16postgres_fdw: Remove useless DO block in testPeter Eisentraut
Discussion: https://www.postgresql.org/message-id/flat/[email protected]
2022-09-14postgres_fdw: Avoid 'variable not found in subplan target list' error.Etsuro Fujita
The tlist of the EvalPlanQual outer plan for a ForeignScan node is adjusted to produce a tuple whose descriptor matches the scan tuple slot for the ForeignScan node. But in the case where the outer plan contains an extra Sort node, if the new tlist contained columns required only for evaluating PlaceHolderVars or columns required only for evaluating local conditions, this would cause setrefs.c to fail with the error. The cause of this is that when creating the outer plan by injecting the Sort node into an alternative local join plan that could emit such extra columns as well, we fail to arrange for the outer plan to propagate them up through the Sort node, causing setrefs.c to fail to match up them in the new tlist to what is available from the outer plan. Repair. Per report from Alexander Pyhalov. Richard Guo and Etsuro Fujita, reviewed by Alexander Pyhalov and Tom Lane. Backpatch to all supported versions. Discussion: http://postgr.es/m/cfb17bf6dfdf876467bd5ef533852d18%40postgrespro.ru
2022-08-05postgres_fdw: Disable batch insertion when there are WCO constraints.Etsuro Fujita
When inserting a view referencing a foreign table that has WITH CHECK OPTION constraints, in single-insert mode postgres_fdw retrieves the data that was actually inserted on the remote side so that the WITH CHECK OPTION constraints are enforced with the data locally, but in batch-insert mode it cannot currently retrieve the data (except for the row first inserted through the view), resulting in enforcing the WITH CHECK OPTION constraints with the data passed from the core (except for the first-inserted row), which led to incorrect results when inserting into a view referencing a foreign table in which a remote BEFORE ROW INSERT trigger changes the rows inserted through the view so that they violate the view's WITH CHECK OPTION constraint. Also, the query inserting into the view caused an assertion failure in assert-enabled builds. Fix these by disabling batch insertion when inserting into such a view. Back-patch to v14 where batch insertion was added. Discussion: https://postgr.es/m/CAPmGK17LpbTZs4m4a_6THP54UBeK9fHvX8aVVA%2BC6yEZDZwQcg%40mail.gmail.com
2022-08-02Improve performance of ORDER BY / DISTINCT aggregatesDavid Rowley
ORDER BY / DISTINCT aggreagtes have, since implemented in Postgres, been executed by always performing a sort in nodeAgg.c to sort the tuples in the current group into the correct order before calling the transition function on the sorted tuples. This was not great as often there might be an index that could have provided pre-sorted input and allowed the transition functions to be called as the rows come in, rather than having to store them in a tuplestore in order to sort them once all the tuples for the group have arrived. Here we change the planner so it requests a path with a sort order which supports the most amount of ORDER BY / DISTINCT aggregate functions and add new code to the executor to allow it to support the processing of ORDER BY / DISTINCT aggregates where the tuples are already sorted in the correct order. Since there can be many ORDER BY / DISTINCT aggregates in any given query level, it's very possible that we can't find an order that suits all of these aggregates. The sort order that the planner chooses is simply the one that suits the most aggregate functions. We take the most strictly sorted variation of each order and see how many aggregate functions can use that, then we try again with the order of the remaining aggregates to see if another order would suit more aggregate functions. For example: SELECT agg(a ORDER BY a),agg2(a ORDER BY a,b) ... would request the sort order to be {a, b} because {a} is a subset of the sort order of {a,b}, but; SELECT agg(a ORDER BY a),agg2(a ORDER BY c) ... would just pick a plan ordered by {a} (we give precedence to aggregates which are earlier in the targetlist). SELECT agg(a ORDER BY a),agg2(a ORDER BY b),agg3(a ORDER BY b) ... would choose to order by {b} since two aggregates suit that vs just one that requires input ordered by {a}. Author: David Rowley Reviewed-by: Ronan Dunklau, James Coleman, Ranier Vilela, Richard Guo, Tom Lane Discussion: https://postgr.es/m/CAApHDvpHzfo92%3DR4W0%2BxVua3BUYCKMckWAmo-2t_KiXN-wYH%3Dw%40mail.gmail.com
2022-07-17postgres_fdw: be more wary about shippability of reg* constants.Tom Lane
Don't consider a constant of regconfig or other reg* types to be shippable unless it refers to a built-in object, or an object in an extension that's been marked shippable. Without this restriction, we're too likely to send a constant that will fail to parse on the remote server. For the regconfig type only, consider OIDs up to 16383 to be "built in", rather than the normal cutoff of 9999. Otherwise the initdb-created text search configurations will be considered unshippable, which is unlikely to make anyone happy. It's possible that this new restriction will de-optimize queries that were working satisfactorily before. Users can restore any lost performance by making sure that objects that can be expected to exist on the remote side are in shippable extensions. However, that's not a change that people are likely to be happy about having to make after a minor-release update. Between that consideration and the lack of field complaints, let's just change this in HEAD. Noted while fixing bug #17483, although this is not precisely the problem that that report complained about. Discussion: https://postgr.es/m/[email protected]
2022-07-17postgres_fdw: set search_path to 'pg_catalog' while deparsing constants.Tom Lane
The motivation for this is to ensure successful transmission of the values of constants of regconfig and other reg* types. The remote will be reading them with search_path = 'pg_catalog', so schema qualification is necessary when referencing objects in other schemas. Per bug #17483 from Emmanuel Quincerot. Back-patch to all supported versions. (There's some other stuff to do here, but it's less back-patchable.) Discussion: https://postgr.es/m/[email protected]
2022-07-12Support TRUNCATE triggers on foreign tables.Fujii Masao
Now some foreign data wrappers support TRUNCATE command. So it's useful to support TRUNCATE triggers on foreign tables for audit logging or for preventing undesired truncation. Author: Yugo Nagata Reviewed-by: Fujii Masao, Ian Lawrence Barwick Discussion: https://postgr.es/m/[email protected]
2022-04-28Disable asynchronous execution if using gating Result nodes.Etsuro Fujita
mark_async_capable_plan(), which is called from create_append_plan() to determine whether subplans are async-capable, failed to take into account that the given subplan created from a given subpath might include a gating Result node if the subpath is a SubqueryScanPath or ForeignPath, causing a segmentation fault there when the subplan created from a SubqueryScanPath includes the Result node, or causing ExecAsyncRequest() to throw an error about an unrecognized node type when the subplan created from a ForeignPath includes the Result node, because in the latter case the Result node was unintentionally considered as async-capable, but we don't currently support executing Result nodes asynchronously. Fix by modifying mark_async_capable_plan() to disable asynchronous execution in such cases. Also, adjust code in the ProjectionPath case in mark_async_capable_plan(), for consistency with other cases, and adjust/improve comments there. is_async_capable_path() added in commit 27e1f1456, which was rewritten to mark_async_capable_plan() in a later commit, has the same issue, causing the error at execution mentioned above, so back-patch to v14 where the aforesaid commit went in. Per report from Justin Pryzby. Etsuro Fujita, reviewed by Zhihong Yu and Justin Pryzby. Discussion: https://postgr.es/m/20220408124338.GK24419%40telsasoft.com
2022-04-21postgres_fdw: Disable batch insert when BEFORE ROW INSERT triggers exist.Etsuro Fujita
Previously, we allowed this, but such triggers might query the table to insert into and act differently if the tuples that have already been processed and prepared for insertion are not there, so disable it in such cases. Back-patch to v14 where batch insert was added. Discussion: https://postgr.es/m/CAPmGK16_uPqsmgK0-LpLSUk54_BoK13bPrhxhfjSoSTVz414hA%40mail.gmail.com
2022-04-06Allow asynchronous execution in more cases.Etsuro Fujita
In commit 27e1f1456, create_append_plan() only allowed the subplan created from a given subpath to be executed asynchronously when it was an async-capable ForeignPath. To extend coverage, this patch handles cases when the given subpath includes some other Path types as well that can be omitted in the plan processing, such as a ProjectionPath directly atop an async-capable ForeignPath, allowing asynchronous execution in partitioned-scan/partitioned-join queries with non-Var tlist expressions and more UNION queries. Andrey Lepikhov and Etsuro Fujita, reviewed by Alexander Pyhalov and Zhihong Yu. Discussion: https://postgr.es/m/659c37a8-3e71-0ff2-394c-f04428c76f08%40postgrespro.ru
2022-03-31Fix postgres_fdw to check shippability of sort clauses properly.Tom Lane
postgres_fdw would push ORDER BY clauses to the remote side without verifying that the sort operator is safe to ship. Moreover, it failed to print a suitable USING clause if the sort operator isn't default for the sort expression's type. The net result of this is that the remote sort might not have anywhere near the semantics we expect, which'd be disastrous for locally-performed merge joins in particular. We addressed similar issues in the context of ORDER BY within an aggregate function call in commit 7012b132d, but failed to notice that query-level ORDER BY was broken. Thus, much of the necessary logic already existed, but it requires refactoring to be usable in both cases. Back-patch to all supported branches. In HEAD only, remove the core code's copy of find_em_expr_for_rel, which is no longer used and really should never have been pushed into equivclass.c in the first place. Ronan Dunklau, per report from David Rowley; reviews by David Rowley, Ranier Vilela, and myself Discussion: https://postgr.es/m/CAApHDvr4OeC2DBVY--zVP83-K=bYrTD7F8SZDhN4g+pj2f2S-A@mail.gmail.com
2022-02-24postgres_fdw: Add support for parallel commit.Etsuro Fujita
postgres_fdw commits remote (sub)transactions opened on remote server(s) in a local (sub)transaction one by one when the local (sub)transaction commits. This patch allows it to commit the remote (sub)transactions in parallel to improve performance. This is enabled by the server option "parallel_commit". The default is false. Etsuro Fujita, reviewed by Fujii Masao and David Zhang. Discussion: http://postgr.es/m/CAPmGK17dAZCXvwnfpr1eTfknTGdt%3DhYTV9405Gt5SqPOX8K84w%40mail.gmail.com
2022-02-18postgres_fdw: Make postgres_fdw.application_name support more escape sequences.Fujii Masao
Commit 6e0cb3dec1 allowed postgres_fdw.application_name to include escape sequences %a (application name), %d (database name), %u (user name) and %p (pid). In addition to them, this commit makes it support the escape sequences for session ID (%c) and cluster name (%C). These are helpful to investigate where each remote transactions came from. Author: Fujii Masao Reviewed-by: Ryohei Takahashi, Kyotaro Horiguchi Discussion: https://postgr.es/m/[email protected]
2022-01-27postgres_fdw: Fix handling of a pending asynchronous request in ↵Etsuro Fujita
postgresReScanForeignScan(). Commit 27e1f1456 failed to process a pending asynchronous request made for a given ForeignScan node in postgresReScanForeignScan() (if any) in cases where we would only reset the next_tuple counter in that function, contradicting the assumption that there should be no pending asynchronous requests that have been made for async-capable subplans for the parent Append node after ReScan. This led to an assert failure in an assert-enabled build. I think this would also lead to mis-rewinding the cursor in that function in the case where we have already fetched one batch for the ForeignScan node and the asynchronous request has been made for the second batch, because even in that case we would just reset the counter when called from that function, so we would fail to execute MOVE BACKWARD ALL. To fix, modify that function to process the asynchronous request before restarting the scan. While at it, add a comment to a function to match other places. Per bug #17344 from Alexander Lakhin. Back-patch to v14 where the aforesaid commit came in. Patch by me. Test case by Alexander Lakhin, adjusted by me. Reviewed and tested by Alexander Lakhin and Dmitry Dolgov. Discussion: https://postgr.es/m/[email protected]
2022-01-07postgres_fdw: Add regression test for postgres_fdw.application_name GUC.Fujii Masao
Commit 449ab63505 added postgres_fdw.application_name GUC that specifies a value for application_name configuration parameter used when postgres_fdw establishes a connection to a foreign server. Also commit 6e0cb3dec1 allowed it to include escape sequences. Both commits added the regression tests for the GUC, but those tests were reverted by commits 98dbef90eb and 5e64ad3697 because they were unstable and caused some buildfarm members to report the failure. This is the third try to add the regression test for postgres_fdw.application_name GUC. One of issues to make the test unstable was to have used postgres_fdw_disconnect_all() to close the existing remote connections. The test expected that the remote connection and its corresponding backend at the remote server disappeared just after postgres_fdw_disconnect_all() was executed, but it could take a bit time for them to disappear. To make sure that they exit, this commit makes the test use pg_terminate_backend() with the timeout at the remote server, instead. If the timeout is set to greater than zero, this function waits until they are actually terminated (or until the given time has passed). Another issue was that the test didn't take into consideration the case where postgres_fdw.application_name containing some escape sequences was converted to the string larger than NAMEDATALEN. In this case it was truncated to less than NAMEDATALEN when it's passed to the remote server, but the test expected wrongly that full string of application_name was always viewable. This commit changes the test so that it can handle that case. Author: Fujii Masao Reviewed-by: Masahiko Sawada, Hayato Kuroda, Kyotaro Horiguchi Discussion: https://postgr.es/m/[email protected] Discussion: https://postgr.es/m/[email protected] Discussion: https://postgr.es/m/[email protected]
2021-12-24postgres_fdw: Revert unstable tests for postgres_fdw.application_name.Fujii Masao
Commit 6e0cb3dec1 added the tests that check that escape sequences in postgres_fdw.application_name setting are replaced with status information expectedly. But they were unstable and caused some buildfarm members to report the failure. This commit reverts those unstable tests.
2021-12-24postgres_fdw: Allow postgres_fdw.application_name to include escape sequences.Fujii Masao
application_name that used when postgres_fdw establishes a connection to a foreign server can be specified in either or both a connection parameter of a server object and GUC postgres_fdw.application_name. This commit allows those parameters to include escape sequences that begins with % character. Then postgres_fdw replaces those escape sequences with status information. For example, %d and %u are replaced with user name and database name in local server, respectively. This feature enables us to add information more easily to track remote transactions or queries, into application_name of a remote connection. Author: Hayato Kuroda Reviewed-by: Kyotaro Horiguchi, Masahiro Ikeda, Hou Zhijie, Fujii Masao Discussion: https://postgr.es/m/TYAPR01MB5866FAE71C66547C64616584F5EB9@TYAPR01MB5866.jpnprd01.prod.outlook.com Discussion: https://postgr.es/m/TYCPR01MB5870D1E8B949DAF6D3B84E02F5F29@TYCPR01MB5870.jpnprd01.prod.outlook.com
2021-12-22Remove assertion for ALTER TABLE .. DETACH PARTITION CONCURRENTLYMichael Paquier
One code path related to this flavor of ALTER TABLE was checking that the relation to detach has to be a normal table or a partitioned table, which would fail if using the command with a different relation kind. Views, sequences and materialized views cannot be part of a partition tree, so these would cause the command to fail anyway, but the assertion was triggered. Foreign tables can be part of a partition tree, and again the assertion would have failed. The simplest solution is just to remove this assertion, so as we get the same failure as the non-concurrent code path. While on it, add a regression test in postgres_fdw for the concurrent partition detach of a foreign table, as per a suggestion from Alexander Lakhin. Issue introduced in 71f4c8c. Reported-by: Alexander Lakhin Author: Michael Paquier, Alexander Lakhin Reviewed-by: Peter Eisentraut, Kyotaro Horiguchi Discussion: https://postgr.es/m/[email protected] Backpatch-through: 14
2021-11-17Improve publication error messagesDaniel Gustafsson
Commit 81d5995b4b introduced more fine-grained errormessages for incorrect relkinds for publication, while unlogged and temporary tables were reported with using the same message. This provides separate error messages for these types of relpersistence. Author: Bharath Rupireddy <[email protected]> Reviewed-by: Peter Eisentraut <[email protected]> Reviewed-by: Jeevan Ladhe <[email protected]> Reviewed-by: Euler Taveira <[email protected]> Discussion: https://postgr.es/m/CALj2ACW9S=AswyQHjtO6WMcsergMkCBTtzXGrM8DX26DzfeTLQ@mail.gmail.com
2021-11-12postgres_fdw: suppress casts on constants in limited cases.Tom Lane
When deparsing an expression of the form "remote_var OP constant", we'd normally apply a cast to the constant to make sure that the remote parser thinks it's of the same type we do. However, doing so is often not necessary, and it causes problems if the user has intentionally declared the local column as being of a different type than the remote column. A plausible use-case for that is using text to represent a type that's an enum on the remote side. A comparison on such a column will get shipped as "var = 'foo'::text", which blows up on the remote side because there's no enum = text operator. But if we simply leave off the explicit cast, the comparison will do exactly what the user wants. It's possible to do this without major risk of semantic problems, by relying on the longstanding parser heuristic that "if one operand of an operator is of type unknown, while the other one has a known type, assume that the unknown operand is also of that type". Hence, this patch leaves off the cast only if (a) the operator inputs have the same type locally; (b) the constant will print as a string literal or NULL, both of which are initially taken as type unknown; and (c) the non-Const input is a plain foreign Var. Rule (c) guarantees that the remote parser will know the type of the non-Const input; moreover, it means that if this cast-omission does cause any semantic surprises, that can only happen in cases where the local column has a different type than the remote column. That wasn't guaranteed to work anyway, and this patch should represent a net usability gain for such cases. One point that I (tgl) remain slightly uncomfortable with is that we will ignore an implicit RelabelType when deciding if the non-Const input is a plain Var. That makes it a little squishy to argue that the remote should resolve the Const as being of the same type as its Var, because then our Const is not the same type as our Var. However, if we don't do that, then this hack won't work as desired if the user chooses to use varchar rather than text to represent some remote column. That seems useful, so do it like this for now. We might have to give up the RelabelType-ignoring bit if any problems surface. Dian Fay, with review and kibitzing by me Discussion: https://postgr.es/m/C9LU294V7K4F.34LRRDU449O45@lamia
2021-10-26Improve HINT message that FDW reports when there are no valid options.Fujii Masao
The foreign data wrapper's validator function provides a HINT message with list of valid options for the object specified in CREATE or ALTER command, when the option given in the command is invalid. Previously postgresql_fdw_validator() and the validator functions for postgres_fdw and dblink_fdw worked in that way even there were no valid options in the object, which could lead to the HINT message with empty list (because there were no valid options). For example, ALTER FOREIGN DATA WRAPPER postgres_fdw OPTIONS (format 'csv') reported the following ERROR and HINT messages. This behavior was confusing. ERROR: invalid option "format" HINT: Valid options in this context are: There is no such issue in file_fdw. The validator function for file_fdw reports the HINT message "There are no valid options in this context." instead in that case. This commit improves postgresql_fdw_validator() and the validator functions for postgres_fdw and dblink_fdw so that they do likewise. For example, this change causes the above ALTER FOREIGN DATA WRAPPER command to report the following messages. ERROR: invalid option "nonexistent" HINT: There are no valid options in this context. Author: Kosei Masumura Reviewed-by: Bharath Rupireddy, Fujii Masao Discussion: https://postgr.es/m/[email protected]
2021-10-06Fix null-pointer crash in postgres_fdw's conversion_error_callback.Tom Lane
Commit c7b7311f6 adjusted conversion_error_callback to always use information from the query's rangetable, to avoid doing catalog lookups in an already-failed transaction. However, as a result of the utterly inadequate documentation for make_tuple_from_result_row, I failed to realize that fsstate could be NULL in some contexts. That led to a crash if we got a conversion error in such a context. Fix by falling back to the previous coding when fsstate is NULL. Improve the commentary, too. Per report from Andrey Borodin. Back-patch to 9.6, like the previous patch. Discussion: https://postgr.es/m/[email protected]
2021-09-10Revoke PUBLIC CREATE from public schema, now owned by pg_database_owner.Noah Misch
This switches the default ACL to what the documentation has recommended since CVE-2018-1058. Upgrades will carry forward any old ownership and ACL. Sites that declined the 2018 recommendation should take a fresh look. Recipes for commissioning a new database cluster from scratch may need to create a schema, grant more privileges, etc. Out-of-tree test suites may require such updates. Reviewed by Peter Eisentraut. Discussion: https://postgr.es/m/[email protected]
2021-09-08postgres_fdw: Revert unstable tests for postgres_fdw.application_name.Fujii Masao
Commit 449ab63505 added the tests that check that postgres_fdw.application_name GUC works as expected. But they were unstable and caused some buildfarm members to report the failure. This commit reverts those unstable tests. Reported-by: Tom Lane as per buildfarm Discussion: https://postgr.es/m/[email protected]
2021-09-07postgres_fdw: Allow application_name of remote connection to be set via GUC.Fujii Masao
This commit adds postgres_fdw.application_name GUC which specifies a value for application_name configuration parameter used when postgres_fdw establishes a connection to a foreign server. This GUC setting always overrides application_name option of the foreign server object. This GUC is useful when we want to specify our own application_name per remote connection. Previously application_name of a remote connection could be set basically only via options of a server object. But which meant that every session connecting to the same foreign server basically should use the same application_name. Also if we want to change the setting, we had to execute "ALTER SERVER ... OPTIONS ..." command. It was inconvenient. Author: Hayato Kuroda Reviewed-by: Masahiro Ikeda, Fujii Masao Discussion: https://postgr.es/m/TYCPR01MB5870D1E8B949DAF6D3B84E02F5F29@TYCPR01MB5870.jpnprd01.prod.outlook.com
2021-08-05postgres_fdw: Fix issues with generated columns in foreign tables.Etsuro Fujita
postgres_fdw imported generated columns from the remote tables as plain columns, and caused failures like "ERROR: cannot insert a non-DEFAULT value into column "foo"" when inserting into the foreign tables, as it tried to insert values into the generated columns. To fix, we do the following under the assumption that generated columns in a postgres_fdw foreign table are defined so that they represent generated columns in the underlying remote table: * Send DEFAULT for the generated columns to the foreign server on insert or update, not generated column values computed on the local server. * Add to postgresImportForeignSchema() an option "import_generated" to include column generated expressions in the definitions of foreign tables imported from a foreign server. The option is true by default. The assumption seems reasonable, because that would make a query of the postgres_fdw foreign table return values for the generated columns that are consistent with the generated expression. While here, fix another issue in postgresImportForeignSchema(): it tried to include column generated expressions as column default expressions in the foreign table definitions when the import_default option was enabled. Per bug #16631 from Daniel Cherniy. Back-patch to v12 where generated columns were added. Discussion: https://postgr.es/m/16631-e929fe9db0ffc7cf%40postgresql.org
2021-07-30In postgres_fdw, allow CASE expressions to be pushed to the remote server.Tom Lane
This is simple enough except for the need to check whether CaseTestExpr nodes have a collation that is not derived from a remote Var. For that, examine the CASE's "arg" expression and then pass that info down into the recursive examination of the WHEN expressions. Alexander Pyhalov, reviewed by Gilles Darold and myself Discussion: https://postgr.es/m/[email protected]
2021-07-30postgres_fdw: Fix handling of pending asynchronous requests.Etsuro Fujita
A pending asynchronous request is handled by process_pending_request(), which previously not only processed an in-progress remote query but performed ExecForeignScan() to produce a tuple to return to the local server asynchronously from the result of the remote query. But that led to a server crash when executing a query or led to an "InstrStartNode called twice in a row" or "InstrEndLoop called on running node" failure when doing EXPLAIN ANALYZE of it, in cases where the plan tree for it contained multiple async-capable nodes accessing the same initplan/subplan that contained multiple async-capable nodes scanning the same foreign tables as for the parent async-capable nodes, as reported by Andrey Lepikhov. The reason is that the second step in process_pending_request() invoked when executing the initplan/subplan for one of the parent async-capable nodes caused recursive execution of the initplan/subplan for another of the parent async-capable nodes. To fix, split process_pending_request() into the two steps and postpone the second step until ForeignAsyncConfigureWait() is called for each of the pending asynchronous requests. Also, in ExecAppendAsyncEventWait() we assumed that FDWs would register at least one wait event in a WaitEventSet created there when they were called from ForeignAsyncConfigureWait() in that function, but allow FDWs to register zero wait events in the WaitEventSet; modify ExecAppendAsyncEventWait() to just return in that case. Oversight in commit 27e1f1456. Back-patch to v14 where that commit went in. Andrey Lepikhov and Etsuro Fujita Discussion: https://postgr.es/m/[email protected]
2021-07-14Change the name of the Result Cache node to MemoizeDavid Rowley
"Result Cache" was never a great name for this node, but nobody managed to come up with another name that anyone liked enough. That was until David Johnston mentioned "Node Memoization", which Tom Lane revised to just "Memoize". People seem to like "Memoize", so let's do the rename. Reviewed-by: Justin Pryzby Discussion: https://postgr.es/m/[email protected] Backpatch-through: 14, where Result Cache was introduced
2021-07-13Rename debug_invalidate_system_caches_always to debug_discard_caches.Tom Lane
The name introduced by commit 4656e3d66 was agreed to be unreasonably long. To match this change, rename initdb's recently-added --clobber-cache option to --discard-caches. Discussion: https://postgr.es/m/[email protected]
2021-07-07Fix crash in postgres_fdw for provably-empty remote UPDATE/DELETE.Tom Lane
In 86dc90056, I'd written find_modifytable_subplan with the assumption that if the immediate child of a ModifyTable is a Result, it must be a projecting Result with a subplan. However, if the UPDATE or DELETE has a provably-constant-false WHERE clause, that's not so: we'll generate a dummy subplan with a childless Result. Add the missing null-check so we don't crash on such cases. Per report from Alexander Pyhalov. Discussion: https://postgr.es/m/[email protected]
2021-07-07postgres_fdw: Tighten up allowed values for batch_size, fetch_size options.Fujii Masao
Previously the values such as '100$%$#$#', '9,223,372,' were accepted and treated as valid integers for postgres_fdw options batch_size and fetch_size. Whereas this is not the case with fdw_startup_cost and fdw_tuple_cost options for which an error is thrown. This was because endptr was not used while converting strings to integers using strtol. This commit changes the logic so that it uses parse_int function instead of strtol as it serves the purpose by returning false in case if it is unable to convert the string to integer. Note that this function also rounds off the values such as '100.456' to 100 and '100.567' or '100.678' to 101. While on this, use parse_real for fdw_startup_cost and fdw_tuple_cost options. Since parse_int and parse_real are being used for reloptions and GUCs, it is more appropriate to use in postgres_fdw rather than using strtol and strtod directly. Back-patch to v14. Author: Bharath Rupireddy Reviewed-by: Ashutosh Bapat, Tom Lane, Kyotaro Horiguchi, Fujii Masao Discussion: https://postgr.es/m/CALj2ACVMO6wY5Pc4oe1OCgUOAtdjHuFsBDw8R5uoYR86eWFQDA@mail.gmail.com
2021-07-06Avoid doing catalog lookups in postgres_fdw's conversion_error_callback.Tom Lane
As in 50371df26, this is a bad idea since the callback can't really know what error is being thrown and thus whether or not it is safe to attempt catalog accesses. Rather than pushing said accesses into the mainline code where they'd usually be a waste of cycles, we can look at the query's rangetable instead. This change does mean that we'll be printing query aliases (if any were used) rather than the table or column's true name. But that doesn't seem like a bad thing: it's certainly a more useful definition in self-join cases, for instance. In any case, it seems unlikely that any applications would be depending on this detail, so it seems safe to change. Patch by me. Original complaint by Andres Freund; Bharath Rupireddy noted the connection to conversion_error_callback. Discussion: https://postgr.es/m/[email protected]
2021-06-24Further stabilize postgres_fdw test.Tom Lane
The queries involving ft1_nopw don't stably return the same row anymore. I surmise that an autovacuum hitting "S 1"."T 1" right after the updates introduced by f61db909d/5843659d0 freed some space, changing where subsequent insertions get stored. It's only by good luck that these results were stable before, though, since a LIMIT without ORDER BY isn't well defined, and it's not like we've ever treated that table as append-only in this test script. Since we only really care whether these commands succeed or not, just replace "SELECT *" with "SELECT 1". Report: https://buildfarm.postgresql.org/cgi-bin/show_log.pl?nm=crake&dt=2021-06-23%2019%3A52%3A08
2021-06-20Stabilize test case added by commit f61db909d.Tom Lane
Buildfarm members ayu and tern have sometimes shown a different plan than expected for this query. I'd been unable to reproduce that before today, but I finally realized what is happening. If there is a concurrent open transaction (probably an autovacuum run in the buildfarm, but this can also be arranged manually), then the index entries for the rows removed by the DELETE a few lines up are not killed promptly, causing a change in the planner's estimate of the extremal value of ft2.c1, which moves the rowcount estimate for "c1 > 1100" by enough to change the join plan from nestloop to hash. To fix, change the query condition to "c1 > 1000", causing the hash plan to be preferred whether or not a concurrent open transaction exists. Since this UPDATE is tailored to be a no-op, nothing else changes. Report: https://buildfarm.postgresql.org/cgi-bin/show_log.pl?nm=ayu&dt=2021-06-09%2022%3A45%3A48 Report: https://buildfarm.postgresql.org/cgi-bin/show_log.pl?nm=ayu&dt=2021-06-13%2022%3A38%3A18 Report: https://buildfarm.postgresql.org/cgi-bin/show_log.pl?nm=tern&dt=2021-06-20%2004%3A55%3A36
2021-06-16Fix copying data into slots with FDW batchingTomas Vondra
Commit b676ac443b optimized handling of tuple slots with bulk inserts into foreign tables, so that the slots are initialized only once and reused for all batches. The data was however copied into the slots only after the initialization, inserting duplicate values when the slot gets reused. Fixed by moving the ExecCopySlot outside the init branch. The existing postgres_fdw tests failed to catch this due to inserting data into foreign tables without unique indexes, and then checking only the number of inserted rows. This adds a new test with both a unique index and a check of inserted values. Reported-by: Alexander Pyhalov Discussion: https://postgr.es/m/7a8cf8d56b3d18e5c0bccd6cd42d04ac%40postgrespro.ru