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10 hoursRevert "postgres_fdw: Inherit the local transaction's access/deferrable modes."HEADmasterEtsuro Fujita
We concluded that commit e5a3c9d9b is a feature rather than a fix; since it was added after feature freeze, revert it. Reported-by: Fujii Masao <masao.fujii@oss.nttdata.com> Reported-by: Michael Paquier <michael@paquier.xyz> Reported-by: Robert Haas <robertmhaas@gmail.com> Discussion: https://postgr.es/m/ed2296f1-1a6b-4932-b870-5bb18c2591ae%40oss.nttdata.com
7 dayspostgres_fdw: Inherit the local transaction's access/deferrable modes.Etsuro Fujita
Previously, postgres_fdw always 1) opened a remote transaction in READ WRITE mode even when the local transaction was READ ONLY, causing a READ ONLY transaction using it that references a foreign table mapped to a remote view executing a volatile function to write in the remote side, and 2) opened the remote transaction in NOT DEFERRABLE mode even when the local transaction was DEFERRABLE, causing a SERIALIZABLE READ ONLY DEFERRABLE transaction using it to abort due to a serialization failure in the remote side. To avoid these, modify postgres_fdw to open a remote transaction in the same access/deferrable modes as the local transaction. This commit also modifies it to open a remote subtransaction in the same access mode as the local subtransaction. Although these issues exist since the introduction of postgres_fdw, there have been no reports from the field. So it seems fine to just fix them in master only. Author: Etsuro Fujita <etsuro.fujita@gmail.com> Reviewed-by: Ashutosh Bapat <ashutosh.bapat.oss@gmail.com> Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us> Discussion: https://postgr.es/m/CAPmGK16n_hcUUWuOdmeUS%2Bw4Q6dZvTEDHb%3DOP%3D5JBzo-M3QmpQ%40mail.gmail.com
9 daysFix memory leakage in postgres_fdw's DirectModify code path.Tom Lane
postgres_fdw tries to use PG_TRY blocks to ensure that it will eventually free the PGresult created by the remote modify command. However, it's fundamentally impossible for this scheme to work reliably when there's RETURNING data, because the query could fail in between invocations of postgres_fdw's DirectModify methods. There is at least one instance of exactly this situation in the regression tests, and the ensuing session-lifespan leak is visible under Valgrind. We can improve matters by using a memory context reset callback attached to the ExecutorState context. That ensures that the PGresult will be freed when the ExecutorState context is torn down, even if control never reaches postgresEndDirectModify. I have little faith that there aren't other potential PGresult leakages in the backend modules that use libpq. So I think it'd be a good idea to apply this concept universally by creating infrastructure that attaches a reset callback to every PGresult generated in the backend. However, that seems too invasive for v18 at this point, let alone the back branches. So for the moment, apply this narrow fix that just makes DirectModify safe. I have a patch in the queue for the more general idea, but it will have to wait for v19. Author: Tom Lane <tgl@sss.pgh.pa.us> Reviewed-by: Matheus Alcantara <matheusssilv97@gmail.com> Discussion: https://postgr.es/m/2976982.1748049023@sss.pgh.pa.us Backpatch-through: 13
2025-05-08Use 'void *' for arbitrary buffers, 'uint8 *' for byte arraysHeikki Linnakangas
A 'void *' argument suggests that the caller might pass an arbitrary struct, which is appropriate for functions like libc's read/write, or pq_sendbytes(). 'uint8 *' is more appropriate for byte arrays that have no structure, like the cancellation keys or SCRAM tokens. Some places used 'char *', but 'uint8 *' is better because 'char *' is commonly used for null-terminated strings. Change code around SCRAM, MD5 authentication, and cancellation key handling to follow these conventions. Discussion: https://www.postgresql.org/message-id/61be9e31-7b7d-49d5-bc11-721800d89d64@eisentraut.org
2025-05-08Suppress unnecessary explicit sorting for EPQ mergejoin pathRichard Guo
When building a ForeignPath for a joinrel, if there's a possibility that EvalPlanQual will be executed, we must identify a suitable path for EPQ checks. If the outer or inner path of the chosen path is a ForeignPath representing a pushed-down join, we replace it with its fdw_outerpath to ensure that the EPQ check path consists entirely of local joins. If the chosen path is a MergePath, and its outer or inner path is a ForeignPath that is not already well enough ordered, the MergePath will have non-NIL outersortkeys or innersortkeys indicating the desired ordering to be created by an explicit Sort node. If we then replace the outer or inner path with its corresponding fdw_outerpath, and that path is already sufficiently ordered, we end up in an inconsistent state: the MergePath has non-NIL outersortkeys or innersortkeys, and its input path is already properly ordered. This inconsistency can result in an Assert failure or the addition of a redundant Sort node. To fix, check if the new outer or inner path of a MergePath is already properly sorted, and set its outersortkeys or innersortkeys to NIL if so. Bug: #18902 Reported-by: Nikita Kalinin <n.kalinin@postgrespro.ru> Author: Richard Guo <guofenglinux@gmail.com> Reviewed-by: Tender Wang <tndrwang@gmail.com> Discussion: https://postgr.es/m/18902-71c1bed2b9f7c46f@postgresql.org
2025-04-29oauth: Disallow OAuth connections via postgres_fdw/dblinkJacob Champion
A subsequent commit will reclassify oauth_client_secret from dispchar="" to dispchar="*", so that UIs will treat it like a secret. For our FDWs, this change will move that option from SERVER to USER MAPPING, which we need to avoid. But upon further discussion, we don't really want our FDWs to use our builtin Device Authorization flow at all, for several reasons: - the URL and code would be printed to the server logs, not sent over the client connection - tokens are not cached/refreshed, so every single connection has to be manually authorized by a user with a browser - oauth_client_secret needs to belong to the foreign server, but options on SERVER are publicly accessible - all non-superusers would need password_required=false, which is dangerous Future OAuth work can use FDWs as a motivating use case. But for now, disallow all oauth_* connection options for these two extensions. Reviewed-by: Noah Misch <noah@leadboat.com> Discussion: https://postgr.es/m/20250415191435.55.nmisch%40google.com
2025-04-19Fix typos and grammar in the codeMichael Paquier
The large majority of these have been introduced by recent commits done in the v18 development cycle. Author: Alexander Lakhin <exclusion@gmail.com> Discussion: https://postgr.es/m/9a7763ab-5252-429d-a943-b28941e0e28b@gmail.com
2025-04-12Harmonize function parameter names for Postgres 18.Peter Geoghegan
Make sure that function declarations use names that exactly match the corresponding names from function definitions in a few places. These inconsistencies were all introduced during Postgres 18 development. This commit was written with help from clang-tidy, by mechanically applying the same rules as similar clean-up commits (the earliest such commit was commit 035ce1fe).
2025-04-08Speedup child EquivalenceMember lookup in plannerDavid Rowley
When planning queries to partitioned tables, we clone all EquivalenceMembers belonging to the partitioned table into em_is_child EquivalenceMembers for each non-pruned partition. For partitioned tables with large numbers of partitions, this meant the ec_members list could become large and code searching that list would become slow. Effectively, the more partitions which were present, the more searches needed to be performed for operations such as find_ec_member_matching_expr() during create_plan() and the more partitions present, the longer these searches would take, i.e., a quadratic slowdown. To fix this, here we adjust how we store EquivalenceMembers for em_is_child members. Instead of storing these directly in ec_members, these are now stored in a new array of Lists in the EquivalenceClass, which is indexed by the relid. When we want to find EquivalenceMembers belonging to a certain child relation, we can narrow the search to the array element for that relation. To make EquivalenceMember lookup easier and to reduce the amount of code change, this commit provides a pair of functions to allow iteration over the EquivalenceMembers of an EC which also handles finding the child members, if required. Callers that never need to look at child members can remain using the foreach loop over ec_members, which will now often be faster due to only parent-level members being stored there. The actual performance increases here are highly dependent on the number of partitions and the query being planned. Performance increases can be visible with as few as 8 partitions, but the speedup is marginal for such low numbers of partitions. The speedups become much more visible with a few dozen to hundreds of partitions. With some tested queries using 56 partitions, the planner was around 3x faster than before. For use cases with thousands of partitions, these are likely to become significantly faster. Some testing has shown planner speedups of 60x or more with 8192 partitions. Author: Yuya Watari <watari.yuya@gmail.com> Co-authored-by: David Rowley <dgrowleyml@gmail.com> Reviewed-by: David Rowley <dgrowleyml@gmail.com> Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us> Reviewed-by: Andrey Lepikhov <a.lepikhov@postgrespro.ru> Reviewed-by: Alena Rybakina <lena.ribackina@yandex.ru> Reviewed-by: Dmitry Dolgov <9erthalion6@gmail.com> Reviewed-by: Amit Langote <amitlangote09@gmail.com> Reviewed-by: Ashutosh Bapat <ashutosh.bapat.oss@gmail.com> Tested-by: Thom Brown <thom@linux.com> Tested-by: newtglobal postgresql_contributors <postgresql_contributors@newtglobalcorp.com> Discussion: https://postgr.es/m/CAJ2pMkZNCgoUKSE%2B_5LthD%2BKbXKvq6h2hQN8Esxpxd%2Bcxmgomg%40mail.gmail.com
2025-04-04Convert PathKey to use CompareTypePeter Eisentraut
Change the PathKey struct to use CompareType to record the sort direction instead of hardcoding btree strategy numbers. The CompareType is then converted to the index-type-specific strategy when the plan is created. This reduces the number of places btree strategy numbers are hardcoded, and it's a self-contained subset of a larger effort to allow non-btree indexes to behave like btrees. Author: Mark Dilger <mark.dilger@enterprisedb.com> Co-authored-by: Peter Eisentraut <peter@eisentraut.org> Discussion: https://www.postgresql.org/message-id/flat/E72EAA49-354D-4C2E-8EB9-255197F55330@enterprisedb.com
2025-03-26Use PG_MODULE_MAGIC_EXT in our installable shared libraries.Tom Lane
It seems potentially useful to label our shared libraries with version information, now that a facility exists for retrieving that. This patch labels them with the PG_VERSION string. There was some discussion about using semantic versioning conventions, but that doesn't seem terribly helpful for modules with no SQL-level presence; and for those that do have SQL objects, we typically expect them to support multiple revisions of the SQL definitions, so it'd still not be very helpful. I did not label any of src/test/modules/. It seems unnecessary since we don't install those, and besides there ought to be someplace that still provides test coverage for the original PG_MODULE_MAGIC macro. Author: Tom Lane <tgl@sss.pgh.pa.us> Discussion: https://postgr.es/m/dd4d1b59-d0fe-49d5-b28f-1e463b68fa32@gmail.com
2025-03-26postgres_fdw: Fix tests on some Windows variantsPeter Eisentraut
The tests introduced by commit 76563f88cfb only work when Unix-domain sockets are available. This is optional on Windows, and buildfarm member drongo runs without them. To fix, skip the test if Unix-domain sockets are not enabled.
2025-03-25postgres_fdw: Remove redundant check in semijoin_target_ok()Alexander Korotkov
If a var belongs to the innerrel of the joinrel, it's not possible that it belongs to the outerrel. This commit removes the redundant check from the if-clause but keeps it as an assertion. Discussion: https://postgr.es/m/flat/CAHewXN=8aW4hd_W71F7Ua4+_w0=bppuvvTEBFBF6G0NuSXLwUw@mail.gmail.com Author: Tender Wang <tndrwang@gmail.com> Reviewed-by: Alexander Pyhalov <a.yhalov@postgrespro.ru> Backpatch-through: 17
2025-03-25postgres_fdw: Avoid pulling up restrict infos from subqueriesAlexander Korotkov
Semi-join joins below left/right join are deparsed as subqueries. Thus, we can't refer to subqueries vars from upper relations. This commit avoids pulling conditions from them. Reported-by: Robins Tharakan <tharakan@gmail.com> Bug: #18852 Discussion: https://postgr.es/m/CAEP4nAzryLd3gwcUpFBAG9MWyDfMRX8ZjuyY2XXjyC_C6k%2B_Zw%40mail.gmail.com Author: Alexander Pyhalov <a.pyhalov@postgrespro.ru> Reviewed-by: Alexander Korotkov <aekorotkov@gmail.com> Backpatch-through: 17
2025-03-24postgres_fdw: improve security checksPeter Eisentraut
SCRAM pass-through should not bypass the FDW security check as it was implemented for postgres_fdw in commit 761c79508e7. This commit improves the security check by adding new SCRAM pass-through checks to ensure that the required SCRAM connection options are not overwritten by the user mapping or foreign server options. This is meant to match the security requirements for a password-using connection. Since libpq has no SCRAM-specific equivalent of PQconnectionUsedPassword(), we enforce this instead by making the use_scram_passthrough option of postgres_fdw imply require_auth=scram-sha-256. This means that if use_scram_passthrough is set, some situations that might otherwise have worked are preempted, for example GSSAPI with delegated credentials. This could be enhanced in the future if there is desire for more flexibility. Reported-by: Jacob Champion <jacob.champion@enterprisedb.com> Author: Matheus Alcantara <mths.dev@pm.me> Co-authored-by: Jacob Champion <jacob.champion@enterprisedb.com> Reviewed-by: Jacob Champion <jacob.champion@enterprisedb.com> Discussion: https://www.postgresql.org/message-id/flat/CAFY6G8ercA1KES%3DE_0__R9QCTR805TTyYr1No8qF8ZxmMg8z2Q%40mail.gmail.com
2025-03-20Revert workarounds for -Wmissing-braces false positives on old GCCPeter Eisentraut
We have collected several instances of a workaround for GCC bug 53119, which caused false-positive compiler warnings. This bug has long been fixed, but was still seen on the buildfarm, most recently on lapwing with gcc (Debian 4.7.2-5). (The GCC bug tracker mentions that a fix was backported to 4.7.4 and 4.8.3.) That compiler no longer runs warning-free since commit 6fdd5d95634, so we don't need to keep these workarounds. And furthermore, the consensus appears to be that we don't want to keep supporting that era of platform anymore at all. This reverts the following commits: d937904cce6a3d82e4f9c2127de7b59105a134b3 506428d091760650971433f6bc083531c307b368 b449afb582bb9015bfbb85abc10ce122aef9ec70 6392f2a0968c20ecde4d27b6652703ad931fce92 bad0763a4d7be3005eae35d460c73ac4bc7ebaad 5e0c761d0a13c7b4f7c5de618ac38560d74d74d0 and makes a few similar fixes to newer code. Discussion: https://www.postgresql.org/message-id/flat/e170d61f-01ab-4cf9-ab68-91cd1fac62c5%40eisentraut.org Discussion: https://www.postgresql.org/message-id/flat/CA%2BTgmoYEAm-KKZibAP3hSqbTFTjUd47XtVcf3xSFDpyecXX9uQ%40mail.gmail.com
2025-03-18Make it possible for loadable modules to add EXPLAIN options.Robert Haas
Modules can use RegisterExtensionExplainOption to register new EXPLAIN options, and GetExplainExtensionId, GetExplainExtensionState, and SetExplainExtensionState to store related state inside the ExplainState object. Since this substantially increases the amount of code that needs to handle ExplainState-related tasks, move a few bits of existing code to a new file explain_state.c and add the rest of this infrastructure there. See the comments at the top of explain_state.c for further explanation of how this mechanism works. This does not yet provide a way for such such options to do anything useful. The intention is that we'll add hooks for that purpose in a separate commit. Discussion: http://postgr.es/m/CA+TgmoYSzg58hPuBmei46o8D3SKX+SZoO4K_aGQGwiRzvRApLg@mail.gmail.com Reviewed-by: Srinath Reddy <srinath2133@gmail.com> Reviewed-by: Andrei Lepikhov <lepihov@gmail.com> Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us> Reviewed-by: Sami Imseih <samimseih@gmail.com>
2025-03-11Improve EXPLAIN's display of window functions.Tom Lane
Up to now we just punted on showing the window definitions used in a plan, with window function calls represented as "OVER (?)". To improve that, show the window definition implemented by each WindowAgg plan node, and reference their window names in OVER. For nameless window clauses generated by "OVER (...)", assign unique names w1, w2, etc. In passing, re-order the properties shown for a WindowAgg node so that the Run Condition (if any) appears after the Window property and before the Filter (if any). This seems more sensible since the Run Condition is associated with the Window and acts before the Filter. Thanks to David G. Johnston and Álvaro Herrera for design suggestions. Author: Tom Lane <tgl@sss.pgh.pa.us> Reviewed-by: David Rowley <dgrowleyml@gmail.com> Discussion: https://postgr.es/m/144530.1741469955@sss.pgh.pa.us
2025-03-02postgres_fdw: Extend postgres_fdw_get_connections to return remote backend PID.Fujii Masao
This commit adds a new "remote_backend_pid" output column to the postgres_fdw_get_connections function. It returns the process ID of the remote backend, on the foreign server, handling the connection. This enhancement is useful for troubleshooting, monitoring, and reporting. For example, if a connection is unexpectedly closed by the foreign server, the remote backend's PID can help diagnose the cause. No extension version bump is needed, as commit c297a47c5f already handled it for v18~. Author: Sagar Dilip Shedge <sagar.shedge92@gmail.com> Reviewed-by: Fujii Masao <masao.fujii@gmail.com> Discussion: https://postgr.es/m/CAPhYifF25q5xUQWXETfKwhc0YVa_6+tfG9Kw4bCvCjpCWxYs2A@mail.gmail.com
2025-02-27Create explain_format.c and move relevant code there.Robert Haas
explain.c has grown rather large, so move various functions that are principally concerned with output generation to a new source file, explain_format.c, instead of lumping them in with everything else that is part of explain.c Reviewed-by: Peter Geoghegan <pg@bowt.ie> Discussion: http://postgr.es/m/CA+TgmoYutMw1Jgo8BWUmB3TqnOhsEAJiYO=rOQufF4gPLWmkLQ@mail.gmail.com
2025-02-27EXPLAIN: Always use two fractional digits for row counts.Robert Haas
Commit ddb17e387aa28d61521227377b00f997756b8a27 attempted to avoid confusing users by displaying digits after the decimal point only when nloops > 1, since it's impossible to have a fraction row count after a single iteration. However, this made the regression tests unstable since parallal queries will have nloops>1 for all nodes below the Gather or Gather Merge in normal cases, but if the workers don't start in time and the leader finishes all the work, they will suddenly have nloops==1, making it unpredictable whether the digits after the decimal point would be displayed or not. Although 44cbba9a7f51a3888d5087fc94b23614ba2b81f2 seemed to fix the immediate failures, it may still be the case that there are lower-probability failures elsewhere in the regression tests. Various fixes are possible here. For example, it has previously been proposed that we should try to display the digits after the decimal point only if rows/nloops is an integer, but currently rows is storead as a float so it's not theoretically an exact quantity -- precision could be lost in extreme cases. It has also been proposed that we should try to display the digits after the decimal point only if we're under some sort of construct that could potentially cause looping regardless of whether it actually does. While such ideas are not without merit, this patch adopts the much simpler solution of always display two decimal digits. If that approach stands up to scrutiny from the buildfarm and human users, it spares us the trouble of doing anything more complex; if not, we can reassess. This commit incidentally reverts 44cbba9a7f51a3888d5087fc94b23614ba2b81f2, which should no longer be needed. Author: Robert Haas <robertmhaas@gmail.com> Author: Ilia Evdokimov <ilya.evdokimov@tantorlabs.com> Discussion: http://postgr.es/m/CA+TgmoazzVHn8sFOMFAEwoqBTDxKT45D7mvkyeHgqtoD2cn58Q@mail.gmail.com
2025-02-20Remove various unnecessary (char *) castsPeter Eisentraut
Remove a number of (char *) casts that are unnecessary. Or in some cases, rewrite the code to make the purpose of the cast clearer. Reviewed-by: Dagfinn Ilmari Mannsåker <ilmari@ilmari.org> Discussion: https://www.postgresql.org/message-id/flat/fd1fcedb-3492-4fc8-9e3e-74b97f2db6c7%40eisentraut.org
2025-02-07Virtual generated columnsPeter Eisentraut
This adds a new variant of generated columns that are computed on read (like a view, unlike the existing stored generated columns, which are computed on write, like a materialized view). The syntax for the column definition is ... GENERATED ALWAYS AS (...) VIRTUAL and VIRTUAL is also optional. VIRTUAL is the default rather than STORED to match various other SQL products. (The SQL standard makes no specification about this, but it also doesn't know about VIRTUAL or STORED.) (Also, virtual views are the default, rather than materialized views.) Virtual generated columns are stored in tuples as null values. (A very early version of this patch had the ambition to not store them at all. But so much stuff breaks or gets confused if you have tuples where a column in the middle is completely missing. This is a compromise, and it still saves space over being forced to use stored generated columns. If we ever find a way to improve this, a bit of pg_upgrade cleverness could allow for upgrades to a newer scheme.) The capabilities and restrictions of virtual generated columns are mostly the same as for stored generated columns. In some cases, this patch keeps virtual generated columns more restricted than they might technically need to be, to keep the two kinds consistent. Some of that could maybe be relaxed later after separate careful considerations. Some functionality that is currently not supported, but could possibly be added as incremental features, some easier than others: - index on or using a virtual column - hence also no unique constraints on virtual columns - extended statistics on virtual columns - foreign-key constraints on virtual columns - not-null constraints on virtual columns (check constraints are supported) - ALTER TABLE / DROP EXPRESSION - virtual column cannot have domain type - virtual columns are not supported in logical replication The tests in generated_virtual.sql have been copied over from generated_stored.sql with the keyword replaced. This way we can make sure the behavior is mostly aligned, and the differences can be visible. Some tests for currently not supported features are currently commented out. Reviewed-by: Jian He <jian.universality@gmail.com> Reviewed-by: Dean Rasheed <dean.a.rasheed@gmail.com> Tested-by: Shlok Kyal <shlok.kyal.oss@gmail.com> Discussion: https://www.postgresql.org/message-id/flat/a368248e-69e4-40be-9c07-6c3b5880b0a6@eisentraut.org
2025-01-29Handle default NULL insertion a little better.Tom Lane
If a column is omitted in an INSERT, and there's no column default, the code in preptlist.c generates a NULL Const to be inserted. Furthermore, if the column is of a domain type, we wrap the Const in CoerceToDomain, so as to throw a run-time error if the domain has a NOT NULL constraint. That's fine as far as it goes, but there are two problems: 1. We're being sloppy about the type/typmod that the Const is labeled with. It really should have the domain's base type/typmod, since it's the input to CoerceToDomain not the output. This can result in coerce_to_domain inserting a useless length-coercion function (useless because it's being applied to a null). The coercion would typically get const-folded away later, but it'd be better not to create it in the first place. 2. We're not applying expression preprocessing (specifically, eval_const_expressions) to the resulting expression tree. The planner's primary expression-preprocessing pass already happened, so that means the length coercion step and CoerceToDomain node miss preprocessing altogether. This is at the least inefficient, since it means the length coercion and CoerceToDomain will actually be executed for each inserted row, though they could be const-folded away in most cases. Worse, it seems possible that missing preprocessing for the length coercion could result in an invalid plan (for example, due to failing to perform default-function-argument insertion). I'm not aware of any live bug of that sort with core datatypes, and it might be unreachable for extension types as well because of restrictions of CREATE CAST, but I'm not entirely convinced that it's unreachable. Hence, it seems worth back-patching the fix (although I only went back to v14, as the patch doesn't apply cleanly at all in v13). There are several places in the rewriter that are building null domain constants the same way as preptlist.c. While those are before the planner and hence don't have any reachable bug, they're still applying a length coercion that will be const-folded away later, uselessly wasting cycles. Hence, make a utility routine that all of these places can call to do it right. Making this code more careful about the typmod assigned to the generated NULL constant has visible but cosmetic effects on some of the plans shown in contrib/postgres_fdw's regression tests. Discussion: https://postgr.es/m/1865579.1738113656@sss.pgh.pa.us Backpatch-through: 14
2025-01-16Add OLD/NEW support to RETURNING in DML queries.Dean Rasheed
This allows the RETURNING list of INSERT/UPDATE/DELETE/MERGE queries to explicitly return old and new values by using the special aliases "old" and "new", which are automatically added to the query (if not already defined) while parsing its RETURNING list, allowing things like: RETURNING old.colname, new.colname, ... RETURNING old.*, new.* Additionally, a new syntax is supported, allowing the names "old" and "new" to be changed to user-supplied alias names, e.g.: RETURNING WITH (OLD AS o, NEW AS n) o.colname, n.colname, ... This is useful when the names "old" and "new" are already defined, such as inside trigger functions, allowing backwards compatibility to be maintained -- the interpretation of any existing queries that happen to already refer to relations called "old" or "new", or use those as aliases for other relations, is not changed. For an INSERT, old values will generally be NULL, and for a DELETE, new values will generally be NULL, but that may change for an INSERT with an ON CONFLICT ... DO UPDATE clause, or if a query rewrite rule changes the command type. Therefore, we put no restrictions on the use of old and new in any DML queries. Dean Rasheed, reviewed by Jian He and Jeff Davis. Discussion: https://postgr.es/m/CAEZATCWx0J0-v=Qjc6gXzR=KtsdvAE7Ow=D=mu50AgOe+pvisQ@mail.gmail.com
2025-01-16Check return of pg_b64_encode() for errorPeter Eisentraut
Forgotten in commit 761c79508e7. Author: Ranier Vilela <ranier.vf@gmail.com> Discussion: https://www.postgresql.org/message-id/flat/CAEudQAq-3yHsSdWoOOaw%2BgAQYgPMpMGuB5pt2yCXgv-YuxG2Hg%40mail.gmail.com
2025-01-15postgres_fdw: SCRAM authentication pass-throughPeter Eisentraut
This enables SCRAM authentication for postgres_fdw when connecting to a foreign server without having to store a plain-text password on user mapping options. This is done by saving the SCRAM ClientKey and ServeryKey from the client authentication and using those instead of the plain-text password for the server-side SCRAM exchange. The new foreign-server or user-mapping option "use_scram_passthrough" enables this. Co-authored-by: Matheus Alcantara <mths.dev@pm.me> Co-authored-by: Peter Eisentraut <peter@eisentraut.org> Discussion: https://www.postgresql.org/message-id/flat/27b29a35-9b96-46a9-bc1a-914140869dac@gmail.com
2025-01-01Update copyright for 2025Bruce Momjian
Backpatch-through: 13
2024-12-23postgres_fdw: re-issue cancel requests a few times if necessary.Tom Lane
Despite the best efforts of commit 0e5c82380, we're still seeing occasional failures of postgres_fdw's query_cancel test in the buildfarm. Investigation suggests that its 100ms timeout is still not enough to reliably ensure that the remote side starts the query before receiving the cancel request --- and if it hasn't, it will just discard the request because it's idle. We discussed allowing a cancel request to kill the next-received query, but that would have wide and perhaps unpleasant side-effects. What seems safer is to make postgres_fdw do what a human user would likely do, which is issue another cancel request if the first one didn't seem to do anything. We'll keep the same overall 30 second grace period before concluding things are broken, but issue additional cancel requests after 1 second, then 2 more seconds, then 4, then 8. (The next one in series is 16 seconds, but we'll hit the 30 second timeout before that.) Having done that, revert the timeout in query_cancel.sql to 10 ms. That will still be enough on most machines, most of the time, for the remote query to start; but now we're intentionally risking the race condition occurring sometimes in the buildfarm, so that the repeat-cancel code path will get some testing. As before, back-patch to v17. We might eventually contemplate back-patching this further, and/or adding similar logic to dblink. But given the lack of field complaints to date, this feels like mostly an exercise in test case stabilization, so v17 is enough. Discussion: https://postgr.es/m/colnv3lzzmc53iu5qoawynr6qq7etn47lmggqr65ddtpjliq5d@glkveb4m6nop
2024-12-20Introduce CompactAttribute array in TupleDesc, take 2David Rowley
The new compact_attrs array stores a few select fields from FormData_pg_attribute in a more compact way, using only 16 bytes per column instead of the 104 bytes that FormData_pg_attribute uses. Using CompactAttribute allows performance-critical operations such as tuple deformation to be performed without looking at the FormData_pg_attribute element in TupleDesc which means fewer cacheline accesses. For some workloads, tuple deformation can be the most CPU intensive part of processing the query. Some testing with 16 columns on a table where the first column is variable length showed around a 10% increase in transactions per second for an OLAP type query performing aggregation on the 16th column. However, in certain cases, the increases were much higher, up to ~25% on one AMD Zen4 machine. This also makes pg_attribute.attcacheoff redundant. A follow-on commit will remove it, thus shrinking the FormData_pg_attribute struct by 4 bytes. Author: David Rowley Reviewed-by: Andres Freund, Victor Yegorov Discussion: https://postgr.es/m/CAApHDvrBztXP3yx=NKNmo3xwFAFhEdyPnvrDg3=M0RhDs+4vYw@mail.gmail.com
2024-12-11Enable BUFFERS with EXPLAIN ANALYZE by defaultDavid Rowley
The topic of turning EXPLAIN's BUFFERS option on with the ANALYZE option has come up a few times over the past few years. In many ways, doing this seems like a good idea as it may be more obvious to users why a given query is running more slowly than they might expect. Also, from my own (David's) personal experience, I've seen users posting to the mailing lists with two identical plans, one slow and one fast asking why their query is sometimes slow. In many cases, this is due to additional reads. Having BUFFERS on by default may help reduce some of these questions, and if not, make it more obvious to the user before they post, or save a round-trip to the mailing list when additional I/O effort is the cause of the slowness. The general consensus is that we want BUFFERS on by default with ANALYZE. However, there were more than zero concerns raised with doing so. The primary reason against is the additional verbosity, making it harder to read large plans. Another concern was that buffer information isn't always useful so may not make sense to have it on by default. It's currently December, so let's commit this to see if anyone comes forward with a strong objection against making this change. We have over half a year remaining in the v18 cycle where we could still easily consider reverting this if someone were to come forward with a convincing enough reason as to why doing this is a bad idea. There were two patches independently submitted to achieve this goal, one by me and the other by Guillaume. This commit is a mix of both of these patches with some additional work done by me to adjust various additional places in the documentation which include EXPLAIN ANALYZE output. Author: Guillaume Lelarge, David Rowley Reviewed-by: Robert Haas, Greg Sabino Mullane, Michael Christofides Discussion: https://postgr.es/m/CANNMO++W7MM8T0KyXN3ZheXXt-uLVM3aEtZd+WNfZ=obxffUiA@mail.gmail.com
2024-11-28Remove useless casts to (void *)Peter Eisentraut
Many of them just seem to have been copied around for no real reason. Their presence causes (small) risks of hiding actual type mismatches or silently discarding qualifiers Discussion: https://www.postgresql.org/message-id/flat/461ea37c-8b58-43b4-9736-52884e862820@eisentraut.org
2024-11-22Add INT64_HEX_FORMAT and UINT64_HEX_FORMAT to c.h.Nathan Bossart
Like INT64_FORMAT and UINT64_FORMAT, these macros produce format strings for 64-bit integers. However, INT64_HEX_FORMAT and UINT64_HEX_FORMAT generate the output in hexadecimal instead of decimal. Besides introducing these macros, this commit makes use of them in several places. This was originally intended to be part of commit 5d6187d2a2, but I left it out because I felt there was a nonzero chance that back-patching these new macros into c.h could cause problems with third-party code. We tend to be less cautious with such changes in new major versions. Note that UINT64_HEX_FORMAT was originally added in commit ee1b30f128, but it was placed in test_radixtree.c, so it wasn't widely available. This commit moves UINT64_HEX_FORMAT to c.h. Discussion: https://postgr.es/m/ZwQvtUbPKaaRQezd%40nathan
2024-10-28Remove unused #include's from contrib, pl, test .c filesPeter Eisentraut
as determined by IWYU Similar to commit dbbca2cf299, but for contrib, pl, and src/test/. Reviewed-by: Alvaro Herrera <alvherre@alvh.no-ip.org> Discussion: https://www.postgresql.org/message-id/flat/0df1d5b1-8ca8-4f84-93be-121081bde049%40eisentraut.org
2024-10-07Fix Y2038 issues with MyStartTime.Nathan Bossart
Several places treat MyStartTime as a "long", which is only 32 bits wide on some platforms. In reality, MyStartTime is a pg_time_t, i.e., a signed 64-bit integer. This will lead to interesting bugs on the aforementioned systems in 2038 when signed 32-bit integers are no longer sufficient to store Unix time (e.g., "pg_ctl start" hanging). To fix, ensure that MyStartTime is handled as a 64-bit value everywhere. (Of course, users will need to ensure that time_t is 64 bits wide on their system, too.) Co-authored-by: Max Johnson Discussion: https://postgr.es/m/CO1PR07MB905262E8AC270FAAACED66008D682%40CO1PR07MB9052.namprd07.prod.outlook.com Backpatch-through: 12
2024-09-18postgres_fdw: Extend postgres_fdw_get_connections to return user name.Fujii Masao
This commit adds a "user_name" output column to the postgres_fdw_get_connections function, returning the name of the local user mapped to the foreign server for each connection. If a public mapping is used, it returns "public." This helps identify postgres_fdw connections more easily, such as determining which connections are invalid, closed, or used within the current transaction. No extension version bump is needed, as commit c297a47c5f already handled it for v18~. Author: Hayato Kuroda Reviewed-by: Fujii Masao Discussion: https://postgr.es/m/b492a935-6c7e-8c08-e485-3c1d64d7d10f@oss.nttdata.com
2024-08-30Make postgres_fdw's query_cancel test less flaky.Tom Lane
This test occasionally shows +WARNING: could not get result of cancel request due to timeout which appears to be because the cancel request is sometimes unluckily sent to the remote session between queries, and then it's ignored. This patch tries to make that less probable in three ways: 1. Use a test query that does not involve remote estimates, so that no EXPLAINs are sent. 2. Make sure that the remote session is ready-to-go (transaction started, SET commands sent) before we start the timer. 3. Increase the statement_timeout to 100ms, to give the local session enough time to plan and issue the query. We might have to go higher than 100ms to make this adequately stable in the buildfarm, but let's see how it goes. Back-patch to v17 where this test was introduced. Jelte Fennema-Nio and Tom Lane Discussion: https://postgr.es/m/578934.1725045685@sss.pgh.pa.us
2024-08-21Treat number of disabled nodes in a path as a separate cost metric.Robert Haas
Previously, when a path type was disabled by e.g. enable_seqscan=false, we either avoided generating that path type in the first place, or more commonly, we added a large constant, called disable_cost, to the estimated startup cost of that path. This latter approach can distort planning. For instance, an extremely expensive non-disabled path could seem to be worse than a disabled path, especially if the full cost of that path node need not be paid (e.g. due to a Limit). Or, as in the regression test whose expected output changes with this commit, the addition of disable_cost can make two paths that would normally be distinguishible in cost seem to have fuzzily the same cost. To fix that, we now count the number of disabled path nodes and consider that a high-order component of both the startup cost and the total cost. Hence, the path list is now sorted by disabled_nodes and then by total_cost, instead of just by the latter, and likewise for the partial path list. It is important that this number is a count and not simply a Boolean; else, as soon as we're unable to respect disabled path types in all portions of the path, we stop trying to avoid them where we can. Because the path list is now sorted by the number of disabled nodes, the join prechecks must compute the count of disabled nodes during the initial cost phase instead of postponing it to final cost time. Counts of disabled nodes do not cross subquery levels; at present, there is no reason for them to do so, since the we do not postpone path selection across subquery boundaries (see make_subplan). Reviewed by Andres Freund, Heikki Linnakangas, and David Rowley. Discussion: http://postgr.es/m/CA+TgmoZ_+MS+o6NeGK2xyBv-xM+w1AfFVuHE4f_aq6ekHv7YSQ@mail.gmail.com
2024-08-05Restrict accesses to non-system views and foreign tables during pg_dump.Masahiko Sawada
When pg_dump retrieves the list of database objects and performs the data dump, there was possibility that objects are replaced with others of the same name, such as views, and access them. This vulnerability could result in code execution with superuser privileges during the pg_dump process. This issue can arise when dumping data of sequences, foreign tables (only 13 or later), or tables registered with a WHERE clause in the extension configuration table. To address this, pg_dump now utilizes the newly introduced restrict_nonsystem_relation_kind GUC parameter to restrict the accesses to non-system views and foreign tables during the dump process. This new GUC parameter is added to back branches too, but these changes do not require cluster recreation. Back-patch to all supported branches. Reviewed-by: Noah Misch Security: CVE-2024-7348 Backpatch-through: 12
2024-07-26postgres_fdw: Fix bug in connection status check.Fujii Masao
The buildfarm member "hake" reported a failure in the regression test added by commit 857df3cef7, where postgres_fdw_get_connections(true) returned unexpected results. The function postgres_fdw_get_connections(true) checks if a connection is closed by using POLLRDHUP in the requested events and calling poll(). Previously, the function only considered POLLRDHUP or 0 as valid returned events. However, poll() can also return POLLHUP, POLLERR, and/or POLLNVAL. So if any of these events were returned, postgres_fdw_get_connections(true) would report incorrect results. postgres_fdw_get_connections(true) failed to account for these return events. This commit updates postgres_fdw_get_connections(true) to correctly report a closed connection when poll() returns not only POLLRDHUP but also POLLHUP, POLLERR, or POLLNVAL. Discussion: https://postgr.es/m/fd8f6186-9e1e-4b9a-92c5-e71e3697d381@oss.nttdata.com
2024-07-26postgres_fdw: Add connection status check to postgres_fdw_get_connections().Fujii Masao
This commit extends the postgres_fdw_get_connections() function to check if connections are closed. This is useful for detecting closed postgres_fdw connections that could prevent successful transaction commits. Users can roll back transactions immediately upon detecting closed connections, avoiding unnecessary processing of failed transactions. This feature is available only on systems supporting the non-standard POLLRDHUP extension to the poll system call, including Linux. Author: Hayato Kuroda Reviewed-by: Shinya Kato, Zhihong Yu, Kyotaro Horiguchi, Andres Freund Reviewed-by: Onder Kalaci, Takamichi Osumi, Vignesh C, Tom Lane, Ted Yu Reviewed-by: Katsuragi Yuta, Peter Smith, Shubham Khanna, Fujii Masao Discussion: https://postgr.es/m/TYAPR01MB58662809E678253B90E82CE5F5889@TYAPR01MB5866.jpnprd01.prod.outlook.com
2024-07-26postgres_fdw: Add "used_in_xact" column to postgres_fdw_get_connections().Fujii Masao
This commit extends the postgres_fdw_get_connections() function to include a new used_in_xact column, indicating whether each connection is used in the current transaction. This addition is particularly useful for the upcoming feature that will check if connections are closed. By using those information, users can verify if postgres_fdw connections used in a transaction remain open. If any connection is closed, the transaction cannot be committed successfully. In this case users can roll back it immediately without waiting for transaction end. The SQL API for postgres_fdw_get_connections() is updated by this commit and may change in the future. To handle compatibility with older SQL declarations, an API versioning system is introduced, allowing the function to behave differently based on the API version. Author: Hayato Kuroda Reviewed-by: Fujii Masao Discussion: https://postgr.es/m/be9382f7-5072-4760-8b3f-31d6dffa8d62@oss.nttdata.com
2024-07-22postgres_fdw: Split out the query_cancel test to its own fileAlvaro Herrera
This allows us to skip it in Cygwin, where it's reportedly flaky because of platform bugs or something. Backpatch to 17, where the test was introduced by commit 2466d6654f85. Reported-by: Alexander Lakhin <exclusion@gmail.com> Discussion: https://postgr.es/m/e4d0cb33-6be5-e4d5-ae49-9eac3ff2b005@gmail.com
2024-07-19postgres_fdw: Avoid "cursor can only scan forward" error.Etsuro Fujita
Commit d844cd75a disallowed rewind in a non-scrollable cursor to resolve anomalies arising from such a cursor operation. However, this failed to take into account the assumption in postgres_fdw that when rescanning a foreign relation, it can rewind the cursor created for scanning the foreign relation without specifying the SCROLL option, regardless of its scrollability, causing this error when it tried to do such a rewind in a non-scrollable cursor. Fix by modifying postgres_fdw to instead recreate the cursor, regardless of its scrollability, when rescanning the foreign relation. (If we had a way to check its scrollability, we could improve this by rewinding it if it is scrollable and recreating it if not, but we do not have it, so this commit modifies it to recreate it in any case.) Per bug #17889 from Eric Cyr. Devrim Gunduz also reported this problem. Back-patch to v15 where that commit enforced the prohibition. Reviewed by Tom Lane. Discussion: https://postgr.es/m/17889-e8c39a251d258dda%40postgresql.org Discussion: https://postgr.es/m/b415ac3255f8352d1ea921cf3b7ba39e0587768a.camel%40gunduz.org
2024-07-15Check lateral references within PHVs for memoize cache keysRichard Guo
If we intend to generate a Memoize node on top of a path, we need cache keys of some sort. Currently we search for the cache keys in the parameterized clauses of the path as well as the lateral_vars of its parent. However, it turns out that this is not sufficient because there might be lateral references derived from PlaceHolderVars, which we fail to take into consideration. This oversight can cause us to miss opportunities to utilize the Memoize node. Moreover, in some plans, failing to recognize all the cache keys could result in performance regressions. This is because without identifying all the cache keys, we would need to purge the entire cache every time we get a new outer tuple during execution. This patch fixes this issue by extracting lateral Vars from within PlaceHolderVars and subsequently including them in the cache keys. In passing, this patch also includes a comment clarifying that Memoize nodes are currently not added on top of join relation paths. This explains why this patch only considers PlaceHolderVars that are due to be evaluated at baserels. Author: Richard Guo Reviewed-by: Tom Lane, David Rowley, Andrei Lepikhov Discussion: https://postgr.es/m/CAMbWs48jLxn0pAPZpJ50EThZ569Xrw+=4Ac3QvkpQvNszbeoNg@mail.gmail.com
2024-07-05Support "Right Semi Join" plan shapesRichard Guo
Hash joins can support semijoin with the LHS input on the right, using the existing logic for inner join, combined with the assurance that only the first match for each inner tuple is considered, which can be achieved by leveraging the HEAP_TUPLE_HAS_MATCH flag. This can be very useful in some cases since we may now have the option to hash the smaller table instead of the larger. Merge join could likely support "Right Semi Join" too. However, the benefit of swapping inputs tends to be small here, so we do not address that in this patch. Note that this patch also modifies a test query in join.sql to ensure it continues testing as intended. With this patch the original query would result in a right-semi-join rather than semi-join, compromising its original purpose of testing the fix for neqjoinsel's behavior for semi-joins. Author: Richard Guo Reviewed-by: wenhui qiu, Alena Rybakina, Japin Li Discussion: https://postgr.es/m/CAMbWs4_X1mN=ic+SxcyymUqFx9bB8pqSLTGJ-F=MHy4PW3eRXw@mail.gmail.com
2024-06-07postgres_fdw: Refuse to send FETCH FIRST WITH TIES to remote servers.Etsuro Fujita
Previously, when considering LIMIT pushdown, postgres_fdw failed to check whether the query has this clause, which led to pushing false LIMIT clauses, causing incorrect results. This clause has been supported since v13, so we need to do a remote-version check before deciding that it will be safe to push such a clause, but we do not currently have a way to do the check (without accessing the remote server); disable pushing such a clause for now. Oversight in commit 357889eb1. Back-patch to v13, where that commit added the support. Per bug #18467 from Onder Kalaci. Patch by Japin Li, per a suggestion from Tom Lane, with some changes to the comments by me. Review by Onder Kalaci, Alvaro Herrera, and me. Discussion: https://postgr.es/m/18467-7bb89084ff03a08d%40postgresql.org
2024-05-21Re-allow planner to use Merge Append to efficiently implement UNION.Robert Haas
This reverts commit 7204f35919b7e021e8d1bc9f2d76fd6bfcdd2070, thus restoring 66c0185a3 (Allow planner to use Merge Append to efficiently implement UNION) as well as the follow-on commits d5d2205c8, 3b1a7eb28, 7487044d6. Per further discussion on pgsql-release, we wish to ship beta1 with this feature, and patch the bug that was found just before wrap, rather than shipping beta1 with the feature reverted.
2024-05-20Revert commit 66c0185a3 and follow-on patches.Tom Lane
This reverts 66c0185a3 (Allow planner to use Merge Append to efficiently implement UNION) as well as the follow-on commits d5d2205c8, 3b1a7eb28, 7487044d6. In addition to those, 07746a8ef had to be removed then re-applied in a different place, because 66c0185a3 moved the relevant code. The reason for this last-minute thrashing is that depesz found a case in which the patched code creates a completely wrong plan that silently gives incorrect query results. It's unclear what the cause is or how many cases are affected, but with beta1 wrap staring us in the face, there's no time for closer investigation. After we figure that out, we can decide whether to un-revert this for beta2 or hold it for v18. Discussion: https://postgr.es/m/Zktzf926vslR35Fv@depesz.com (also some private discussion among pgsql-release)
2024-04-21Make postgres_fdw request remote time zone 'GMT' not 'UTC'.Tom Lane
This should have the same results for all practical purposes. The advantage of selecting 'GMT' is that it's guaranteed to work even when the remote system's timezone database is missing entries, because pg_tzset() hard-wires handling of that, at least in 9.2 and later. (It seems like it would be a good idea to similarly hard-wire correct handling of 'UTC', but that'll be a little more invasive than I want to consider back-patching. Leave that for another day when we're not in feature freeze.) Per trouble report from Adnan Dautovic. Back-patch to all supported branches. Discussion: https://postgr.es/m/465248.1712211585@sss.pgh.pa.us