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2021-01-16Prevent excess SimpleLruTruncate() deletion.Noah Misch
Every core SLRU wraps around. With the exception of pg_notify, the wrap point can fall in the middle of a page. Account for this in the PagePrecedes callback specification and in SimpleLruTruncate()'s use of said callback. Update each callback implementation to fit the new specification. This changes SerialPagePrecedesLogically() from the style of asyncQueuePagePrecedes() to the style of CLOGPagePrecedes(). (Whereas pg_clog and pg_serial share a key space, pg_serial is nothing like pg_notify.) The bug fixed here has the same symptoms and user followup steps as 592a589a04bd456410b853d86bd05faa9432cbbb. Back-patch to 9.5 (all supported versions). Reviewed by Andrey Borodin and (in earlier versions) by Tom Lane. Discussion: https://postgr.es/m/20190202083822.GC32531@gust.leadboat.com
2021-01-15Disallow CREATE STATISTICS on system catalogsTomas Vondra
Add a check that CREATE STATISTICS does not add extended statistics on system catalogs, similarly to indexes etc. It can be overriden using the allow_system_table_mods GUC. This bug exists since 7b504eb282c, adding the extended statistics, so backpatch all the way back to PostgreSQL 10. Author: Tomas Vondra Reported-by: Dean Rasheed Backpatch-through: 10 Discussion: https://postgr.es/m/CAEZATCXAPrrOKwEsyZKQ4uzzJQWBCt6QAvOcgqRGdWwT1zb%2BrQ%40mail.gmail.com
2021-01-14Prevent drop of tablespaces used by partitioned relationsAlvaro Herrera
When a tablespace is used in a partitioned relation (per commits ca4103025dfe in pg12 for tables and 33e6c34c3267 in pg11 for indexes), it is possible to drop the tablespace, potentially causing various problems. One such was reported in bug #16577, where a rewriting ALTER TABLE causes a server crash. Protect against this by using pg_shdepend to keep track of tablespaces when used for relations that don't keep physical files; we now abort a tablespace if we see that the tablespace is referenced from any partitioned relations. Backpatch this to 11, where this problem has been latent all along. We don't try to create pg_shdepend entries for existing partitioned indexes/tables, but any ones that are modified going forward will be protected. Note slight behavior change: when trying to drop a tablespace that contains both regular tables as well as partitioned ones, you'd previously get ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE and now you'll get ERRCODE_DEPENDENT_OBJECTS_STILL_EXIST. Arguably, the latter is more correct. It is possible to add protecting pg_shdepend entries for existing tables/indexes, by doing ALTER TABLE ONLY some_partitioned_table SET TABLESPACE pg_default; ALTER TABLE ONLY some_partitioned_table SET TABLESPACE original_tablespace; for each partitioned table/index that is not in the database default tablespace. Because these partitioned objects do not have storage, no file needs to be actually moved, so it shouldn't take more time than what's required to acquire locks. This query can be used to search for such relations: SELECT ... FROM pg_class WHERE relkind IN ('p', 'I') AND reltablespace <> 0 Reported-by: Alexander Lakhin <exclusion@gmail.com> Discussion: https://postgr.es/m/16577-881633a9f9894fd5@postgresql.org Author: Álvaro Herrera <alvherre@alvh.no-ip.org> Reviewed-by: Michael Paquier <michael@paquier.xyz>
2020-12-01Avoid memcpy() with a NULL source pointer and count == 0Alvaro Herrera
When memcpy() is called on a pointer, the compiler is entitled to assume that the pointer is not null, which can lead to optimizing nearby code in potentially undesirable ways. We still want such optimizations (gcc's -fdelete-null-pointer-checks) in cases where they're valid. Related: commit 13bba02271dc. Backpatch to pg11, where this particular instance appeared. Reported-by: Ranier Vilela <ranier.vf@gmail.com> Reported-by: Zhihong Yu <zyu@yugabyte.com> Discussion: https://postgr.es/m/CAEudQApUndmQkr5fLrCKXQ7+ib44i7S+Kk93pyVThS85PnG3bQ@mail.gmail.com Discussion: https://postgr.es/m/CALNJ-vSdhwSM5f4tnNn1cdLHvXMVe_S+V3nR5GwNrmCPNB2VtQ@mail.gmail.com
2020-11-30Remove leftover comments, left behind by removal of WITH OIDS.Heikki Linnakangas
Author: Amit Langote Discussion: https://www.postgresql.org/message-id/CA%2BHiwqGaRoF3XrhPW-Y7P%2BG7bKo84Z_h%3DkQHvMh-80%3Dav3wmOw%40mail.gmail.com
2020-11-28Fix a recently-introduced race condition in LISTEN/NOTIFY handling.Tom Lane
Commit 566372b3d fixed some race conditions involving concurrent SimpleLruTruncate calls, but it introduced new ones in async.c. A newly-listening backend could attempt to read Notify SLRU pages that were in process of being truncated, possibly causing an error. Also, the QUEUE_TAIL pointer could become set to a value that's not equal to the queue position of any backend. While that's fairly harmless in v13 and up (thanks to commit 51004c717), in older branches it resulted in near-permanent disabling of the queue truncation logic, so that continued use of NOTIFY led to queue-fill warnings and eventual inability to send any more notifies. (A server restart is enough to make that go away, but it's still pretty unpleasant.) The core of the problem is confusion about whether QUEUE_TAIL represents the "logical" tail of the queue (i.e., the oldest still-interesting data) or the "physical" tail (the oldest data we've not yet truncated away). To fix, split that into two variables. QUEUE_TAIL regains its definition as the logical tail, and we introduce a new variable to track the oldest un-truncated page. Per report from Mikael Gustavsson. Like the previous patch, back-patch to all supported branches. Discussion: https://postgr.es/m/1b8561412e8a4f038d7a491c8b922788@smhi.se
2020-11-16Use "true" not "TRUE" in one ICU function call.Tom Lane
This was evidently missed in commit 6337865f3, which generally did s/TRUE/true/ everywhere. It escaped notice up to now because ICU versions before ICU 68 provided definitions of "TRUE" and "FALSE" regardless. With ICU 68, it fails to compile. Per report from Condor. Back-patch to v11 where 6337865f3 came in. (I've not tested v10, where this call originated, but I imagine it's fine since we defined TRUE in c.h back then.) Discussion: https://postgr.es/m/7a6f3336165bfe3ca66abcda7966f9d0@stz-bg.com
2020-11-15Fix fuzzy thinking about amcanmulticol versus amcaninclude.Tom Lane
These flags should be independent: in particular an index AM should be able to say that it supports include columns without necessarily supporting multiple key columns. The included-columns patch got this wrong, possibly aided by the fact that it didn't bother to update the documentation. While here, clarify some text about amcanreturn, which was a little vague about what should happen when amcanreturn reports that only some of the index columns are returnable. Noted while reviewing the SP-GiST included-columns patch, which quite incorrectly (and unsafely) changed SP-GiST to claim amcanmulticol = true as a workaround for this bug. Backpatch to v11 where included columns were introduced.
2020-11-09In security-restricted operations, block enqueue of at-commit user code.Noah Misch
Specifically, this blocks DECLARE ... WITH HOLD and firing of deferred triggers within index expressions and materialized view queries. An attacker having permission to create non-temp objects in at least one schema could execute arbitrary SQL functions under the identity of the bootstrap superuser. One can work around the vulnerability by disabling autovacuum and not manually running ANALYZE, CLUSTER, REINDEX, CREATE INDEX, VACUUM FULL, or REFRESH MATERIALIZED VIEW. (Don't restore from pg_dump, since it runs some of those commands.) Plain VACUUM (without FULL) is safe, and all commands are fine when a trusted user owns the target object. Performance may degrade quickly under this workaround, however. Back-patch to 9.5 (all supported versions). Reviewed by Robert Haas. Reported by Etienne Stalmans. Security: CVE-2020-25695
2020-11-08In INSERT/UPDATE, use the table's real tuple descriptor as target.Tom Lane
This back-patches commit 20d3fe900 into the v12 and v13 branches. At the time I thought that commit was not fixing any observable bug, but Bertrand Drouvot showed otherwise: adding a dropped column to the previously-considered scenario crashes v12 and v13, unless the dropped column happens to be an integer. That is, of course, because the tupdesc we derive from the plan output tlist fails to describe the dropped column accurately, so that we'll do the wrong thing with a tuple in which that column isn't NULL. There is no bug in pre-v12 branches because they already did use the table's real tuple descriptor for any trigger-returned tuple. It seems that this set of bugs can be blamed on the changes that removed es_trig_tuple_slot, though I've not attempted to pin that down precisely. Although there's no code change needed in HEAD, update the test case to include a dropped column there too. Discussion: https://postgr.es/m/db5d97c8-f48a-51e2-7b08-b73d5434d425@amazon.com Discussion: https://postgr.es/m/16644-5da7ef98a7ac4545@postgresql.org
2020-11-07Message style improvementsAlvaro Herrera
* Avoid pointlessly highlighting that an index vacuum was executed by a parallel worker; user doesn't care. * Don't give the impression that a non-concurrent reindex of an invalid index on a TOAST table would work, because it wouldn't. * Add a "translator:" comment for a mysterious message. Discussion: https://postgr.es/m/20201107034943.GA16596@alvherre.pgsql Reviewed-by: Michael Paquier <michael@paquier.xyz>
2020-11-06Revert "Accept relations of any kind in LOCK TABLE".Tom Lane
Revert 59ab4ac32, as well as the followup fix 33862cb9c, in all branches. We need to think a bit harder about what the behavior of LOCK TABLE on views should be, and there's no time for that before next week's releases. We'll take another crack at this later. Discussion: https://postgr.es/m/16703-e348f58aab3cf6cc@postgresql.org
2020-11-05Don't throw an error for LOCK TABLE on a self-referential view.Tom Lane
LOCK TABLE has complained about "infinite recursion" when applied to a self-referential view, ever since we made it recurse into views in v11. However, that breaks pg_dump's new assumption that it's okay to lock every relation. There doesn't seem to be any good reason to throw an error: if we just abandon the recursion, we've still satisfied the requirement of locking every referenced relation. Per bug #16703 from Andrew Bille (via Alexander Lakhin). Discussion: https://postgr.es/m/16703-e348f58aab3cf6cc@postgresql.org
2020-11-03Allow users with BYPASSRLS to alter their own passwords.Tom Lane
The intention in commit 491c029db was to require superuserness to change the BYPASSRLS property, but the actual effect of the coding in AlterRole() was to require superuserness to change anything at all about a BYPASSRLS role. Other properties of a BYPASSRLS role should be changeable under the same rules as for a normal role, though. Fix that, and also take care of some documentation omissions related to BYPASSRLS and REPLICATION role properties. Tom Lane and Stephen Frost, per bug report from Wolfgang Walther. Back-patch to all supported branches. Discussion: https://postgr.es/m/a5548a9f-89ee-3167-129d-162b5985fcf8@technowledgy.de
2020-11-03Disallow ALTER TABLE ONLY / DROP EXPRESSIONPeter Eisentraut
The current implementation cannot handle this correctly, so just forbid it for now. GENERATED clauses must be attached to the column definition and cannot be added later like DEFAULT, so if a child table has a generation expression that the parent does not have, the child column will necessarily be an attlocal column. So to implement ALTER TABLE ONLY / DROP EXPRESSION, we'd need extra code to update attislocal of the direct child tables, somewhat similar to how DROP COLUMN does it, so that the resulting state can be properly dumped and restored. Discussion: https://www.postgresql.org/message-id/flat/15830.1575468847%40sss.pgh.pa.us
2020-10-27Accept relations of any kind in LOCK TABLEAlvaro Herrera
The restriction that only tables and views can be locked by LOCK TABLE is quite arbitrary, since the underlying mechanism can lock any relation type. Drop the restriction so that programs such as pg_dump can lock all relations they're interested in, preventing schema changes that could cause a dump to fail after expending much effort. Backpatch to 9.5. Author: Álvaro Herrera <alvherre@alvh.no-ip.org> Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us> Reported-by: Wells Oliver <wells.oliver@gmail.com> Discussion: https://postgr.es/m/20201021200659.GA32358@alvherre.pgsql
2020-10-25Fix corner case for a BEFORE ROW UPDATE trigger returning OLD.Tom Lane
If the old row has any "missing" attributes that are supposed to be retrieved from an associated tuple descriptor, the wrong things happened because the trigger result is shoved directly into an executor slot that lacks the missing-attribute data. Notably, CHECK-constraint verification would incorrectly see those columns as NULL, and so would RETURNING-list evaluation. Band-aid around this by forcibly expanding the tuple before passing it to the trigger function. (IMO it was a fundamental misdesign to put the missing-attribute data into tuple constraints, which so much of the system considers to be optional. But we're probably stuck with that now, and will have to continue to apply band-aids as we find other places with similar issues.) Back-patch to v12. v11 would also have the issue, except that commit 920311ab1 already applied a similar band-aid. That forced expansion in more cases than seem really necessary, though, so this isn't a directly equivalent fix. Amit Langote, with some cosmetic changes by me Discussion: https://postgr.es/m/16644-5da7ef98a7ac4545@postgresql.org
2020-10-23Fix broken XML formatting in EXPLAIN output for incremental sorts.Tom Lane
The ExplainCloseGroup arguments for incremental sort usage data didn't match the corresponding ExplainOpenGroup. This only matters for XML-format output, which is probably why we'd not noticed. Daniel Gustafsson, per bug #16683 from Frits Jalvingh Discussion: https://postgr.es/m/16683-8005033324ad34e9@postgresql.org
2020-10-20Fix ALTER TABLE .. ENABLE/DISABLE TRIGGER recursionAlvaro Herrera
More precisely, correctly handle the ONLY flag indicating not to recurse. This was implemented in 86f575948c77 by recursing in trigger.c, but that's the wrong place; use ATSimpleRecursion instead, which behaves properly. However, because legacy inheritance has never recursed in that situation, make sure to do that only for new-style partitioning. I noticed this problem while testing a fix for another bug in the vicinity. This has been wrong all along, so backpatch to 11. Discussion: https://postgr.es/m/20201016235925.GA29829@alvherre.pgsql
2020-09-30Reword partitioning error messageAlvaro Herrera
The error message about columns in the primary key not including all of the partition key was unclear; reword it. Backpatch all the way to pg11, where it appeared. Reported-by: Nagaraj Raj <nagaraj.sf@yahoo.com> Discussion: https://postgr.es/m/64062533.78364.1601415362244@mail.yahoo.com
2020-09-29Fix progress reporting of REINDEX CONCURRENTLYMichael Paquier
This addresses a couple of issues with the so-said subject: - Report the correct parent relation with the index actually being rebuilt or validated. Previously, the command status remained set to the last index created for the progress of the index build and validation, which would be incorrect when working on a table that has more than one index. - Use the correct phase when waiting before the drop of the old indexes. Previously, this was reported with the same status as when waiting before the old indexes are marked as dead. Author: Matthias van de Meent, Michael Paquier Discussion: https://postgr.es/m/CAEze2WhqFgcwe1_tv=sFYhLWV2AdpfukumotJ6JNcAOQs3jufg@mail.gmail.com Backpatch-through: 12
2020-09-28Add for_each_from, to simplify loops starting from non-first list cells.Tom Lane
We have a dozen or so places that need to iterate over all but the first cell of a List. Prior to v13 this was typically written as for_each_cell(lc, lnext(list_head(list))) Commit 1cff1b95a changed these to for_each_cell(lc, list, list_second_cell(list)) This patch introduces a new macro for_each_from() which expresses the start point as a list index, allowing these to be written as for_each_from(lc, list, 1) This is marginally more efficient, since ForEachState.i can be initialized directly instead of backing into it from a ListCell address. It also seems clearer and less typo-prone. Some of the remaining uses of for_each_cell() look like they could profitably be changed to for_each_from(), but here I confined myself to changing uses of list_second_cell(). Also, fix for_each_cell_setup() and for_both_cell_setup() to const-ify their arguments; that's a simple oversight in 1cff1b95a. Back-patch into v13, on the grounds that (1) the const-ification is a minor bug fix, and (2) it's better for back-patching purposes if we only have two ways to write these loops rather than three. In HEAD, also remove list_third_cell() and list_fourth_cell(), which were also introduced in 1cff1b95a, and are unused as of cc99baa43. It seems unlikely that any third-party code would have started to use them already; anyone who has can be directed to list_nth_cell instead. Discussion: https://postgr.es/m/CAApHDvpo1zj9KhEpU2cCRZfSM3Q6XGdhzuAS2v79PH7WJBkYVA@mail.gmail.com
2020-09-26Revise RelationBuildRowSecurity() to avoid memory leaks.Tom Lane
This function leaked some memory while loading qual clauses for an RLS policy. While ordinarily negligible, that could build up in some repeated-reload cases, as reported by Konstantin Knizhnik. We can improve matters by borrowing the coding long used in RelationBuildRuleLock: build stringToNode's result directly in the target context, and remember to explicitly pfree the input string. This patch by no means completely guarantees zero leaks within this function, since we have no real guarantee that the catalog- reading subroutines it calls don't leak anything. However, practical tests suggest that this is enough to resolve the issue. In any case, any remaining leaks are similar to those risked by RelationBuildRuleLock and other relcache-loading subroutines. If we need to fix them, we should adopt a more global approach such as that used by the RECOVER_RELATION_BUILD_MEMORY hack. While here, let's remove the need for an expensive PG_TRY block by using MemoryContextSetParent to reparent an initially-short-lived context for the RLS data. Back-patch to all supported branches. Discussion: https://postgr.es/m/21356c12-8917-8249-b35f-1c447231922b@postgrespro.ru
2020-09-16Avoid unnecessary recursion to child tables in ALTER TABLE SET NOT NULL.Tom Lane
If a partitioned table's column is already marked NOT NULL, there is no need to examine its partitions, because we can rely on previous DDL to have enforced that the child columns are NOT NULL as well. (Unfortunately, the same cannot be said for traditional inheritance, so for now we have to restrict the optimization to partitioned tables.) Hence, we may skip recursing to child tables in this situation. The reason this case is worth worrying about is that when pg_dump dumps a partitioned table having a primary key, it will include the requisite NOT NULL markings in the CREATE TABLE commands, and then add the primary key as a separate step. The primary key addition generates a SET NOT NULL as a subcommand, just to be sure. So the situation where a SET NOT NULL is redundant does arise in the real world. Skipping the recursion does more than just save a few cycles: it means that a command such as "ALTER TABLE ONLY partition_parent ADD PRIMARY KEY" will take locks only on the partition parent table, not on the partitions. It turns out that parallel pg_restore is effectively assuming that that's true, and has little choice but to do so because the dependencies listed for such a TOC entry don't include the partitions. pg_restore could thus issue this ALTER while data restores on the partitions are still in progress. Taking unnecessary locks on the partitions not only hurts concurrency, but can lead to actual deadlock failures, as reported by Domagoj Smoljanovic. (A contributing factor in the deadlock is that TRUNCATE on a child partition wants a non-exclusive lock on the parent. This seems likewise unnecessary, but the fix for it is more invasive so we won't consider back-patching it. Fortunately, getting rid of one of these two poor behaviors is enough to remove the deadlock.) Although support for partitioned primary keys came in with v11, this patch is dependent on the SET NOT NULL refactoring done by commit f4a3fdfbd, so we can only patch back to v12. Patch by me; thanks to Alvaro Herrera and Amit Langote for review. Discussion: https://postgr.es/m/VI1PR03MB31670CA1BD9625C3A8C5DD05EB230@VI1PR03MB3167.eurprd03.prod.outlook.com
2020-09-15Fix use-after-free bug with event triggers in an extension scriptAlvaro Herrera
ALTER TABLE commands in an extension script are added to an event trigger command list; but starting with commit b5810de3f4 they do so in a memory context that's too short-lived, so when execution ends and time comes to use the entries, they've already been freed. (This would also be a problem with ALTER TABLE commands in a multi-command query string, but these serendipitously end in PortalContext -- which probably explains why it took so long for this to be reported.) Fix by using the memory context specifically set for that, instead. Backpatch to 13, where the aforementioned commit appeared. Reported-by: Philippe Beaudoin Author: Jehan-Guillaume de Rorthais <jgdr@dalibo.com> Discussion: https://postgr.es/m/20200902193715.6e0269d4@firost
2020-09-14Message fixes and style improvementsPeter Eisentraut
2020-09-01Raise error on concurrent drop of partitioned indexAlvaro Herrera
We were already raising an error for DROP INDEX CONCURRENTLY on a partitioned table, albeit a different and confusing one: ERROR: DROP INDEX CONCURRENTLY must be first action in transaction Change that to throw a more comprehensible error: ERROR: cannot drop partitioned index \"%s\" concurrently Michael Paquier authored the test case for indexes on temporary partitioned tables. Backpatch to 11, where indexes on partitioned tables were added. Reported-by: Jan Mussler <jan.mussler@zalando.de> Reviewed-by: Michael Paquier <michael@paquier.xyz> Discussion: https://postgr.es/m/16594-d2956ca909585067@postgresql.org
2020-08-22Fix ALTER TABLE's scheduling rules for AT_AddConstraint subcommands.Tom Lane
Commit 1281a5c90 rearranged the logic in this area rather drastically, and it broke the case of adding a foreign key constraint in the same ALTER that adds the pkey or unique constraint it depends on. While self-referential fkeys are surely a pretty niche case, this used to work so we shouldn't break it. To fix, reorganize the scheduling rules in ATParseTransformCmd so that a transformed AT_AddConstraint subcommand will be delayed into a later pass in all cases, not only when it's been spit out as a side-effect of parsing some other command type. Also tweak the logic so that we won't run ATParseTransformCmd twice while doing this. It seems to work even without that, but it's surely wasting cycles to do so. Per bug #16589 from Jeremy Evans. Back-patch to v13 where the new code was introduced. Discussion: https://postgr.es/m/16589-31c8d981ca503896@postgresql.org
2020-08-21Fix handling of CREATE TABLE LIKE with inheritance.Tom Lane
If a CREATE TABLE command uses both LIKE and traditional inheritance, Vars in CHECK constraints and expression indexes that are absorbed from a LIKE parent table tended to get mis-numbered, resulting in wrong answers and/or bizarre error messages (though probably not any actual crashes, thanks to validation occurring in the executor). In v12 and up, the same could happen to Vars in GENERATED expressions, even in cases with no LIKE clause but multiple traditional-inheritance parents. The cause of the problem for LIKE is that parse_utilcmd.c supposed it could renumber such Vars correctly during transformCreateStmt(), which it cannot since we have not yet accounted for columns added via inheritance. Fix that by postponing processing of LIKE INCLUDING CONSTRAINTS, DEFAULTS, GENERATED, INDEXES till after we've performed DefineRelation(). The error with GENERATED and multiple inheritance is a simple oversight in MergeAttributes(); it knows it has to renumber Vars in inherited CHECK constraints, but forgot to apply the same processing to inherited GENERATED expressions (a/k/a defaults). Per bug #16272 from Tom Gottfried. The non-GENERATED variants of the issue are ancient, presumably dating right back to the addition of CREATE TABLE LIKE; hence back-patch to all supported branches. Discussion: https://postgr.es/m/16272-6e32da020e9a9381@postgresql.org
2020-08-21Rework EXPLAIN for planner's buffer usage.Fujii Masao
Commit ce77abe63c allowed EXPLAIN (BUFFERS) to report the information on buffer usage during planning phase. However three issues were reported regarding this feature. (1) Previously, EXPLAIN option BUFFERS required ANALYZE. So the query had to be actually executed by specifying ANALYZE even when we want to see only the planner's buffer usage. This was inconvenient especially when the query was write one like DELETE. (2) EXPLAIN included the planner's buffer usage in summary information. So SUMMARY option had to be enabled to report that. Also this format was confusing. (3) The output structure for planning information was not consistent between TEXT format and the others. For example, "Planning" tag was output in JSON format, but not in TEXT format. For (1), this commit allows us to perform EXPLAIN (BUFFERS) without ANALYZE to report the planner's buffer usage. For (2), this commit changed EXPLAIN output so that the planner's buffer usage is reported before summary information. For (3), this commit made the output structure for planning information more consistent between the formats. Back-patch to v13 where the planner's buffer usage was allowed to be reported in EXPLAIN. Reported-by: Pierre Giraud, David Rowley Author: Fujii Masao Reviewed-by: David Rowley, Julien Rouhaud, Pierre Giraud Discussion: https://postgr.es/m/07b226e6-fa49-687f-b110-b7c37572f69e@dalibo.com
2020-08-15Prevent concurrent SimpleLruTruncate() for any given SLRU.Noah Misch
The SimpleLruTruncate() header comment states the new coding rule. To achieve this, add locktype "frozenid" and two LWLocks. This closes a rare opportunity for data loss, which manifested as "apparent wraparound" or "could not access status of transaction" errors. Data loss is more likely in pg_multixact, due to released branches' thin margin between multiStopLimit and multiWrapLimit. If a user's physical replication primary logged ": apparent wraparound" messages, the user should rebuild standbys of that primary regardless of symptoms. At less risk is a cluster having emitted "not accepting commands" errors or "must be vacuumed" warnings at some point. One can test a cluster for this data loss by running VACUUM FREEZE in every database. Back-patch to 9.5 (all supported versions). Discussion: https://postgr.es/m/20190218073103.GA1434723@rfd.leadboat.com
2020-08-10Make contrib modules' installation scripts more secure.Tom Lane
Hostile objects located within the installation-time search_path could capture references in an extension's installation or upgrade script. If the extension is being installed with superuser privileges, this opens the door to privilege escalation. While such hazards have existed all along, their urgency increases with the v13 "trusted extensions" feature, because that lets a non-superuser control the installation path for a superuser-privileged script. Therefore, make a number of changes to make such situations more secure: * Tweak the construction of the installation-time search_path to ensure that references to objects in pg_catalog can't be subverted; and explicitly add pg_temp to the end of the path to prevent attacks using temporary objects. * Disable check_function_bodies within installation/upgrade scripts, so that any security gaps in SQL-language or PL-language function bodies cannot create a risk of unwanted installation-time code execution. * Adjust lookup of type input/receive functions and join estimator functions to complain if there are multiple candidate functions. This prevents capture of references to functions whose signature is not the first one checked; and it's arguably more user-friendly anyway. * Modify various contrib upgrade scripts to ensure that catalog modification queries are executed with secure search paths. (These are in-place modifications with no extension version changes, since it is the update process itself that is at issue, not the end result.) Extensions that depend on other extensions cannot be made fully secure by these methods alone; therefore, revert the "trusted" marking that commit eb67623c9 applied to earthdistance and hstore_plperl, pending some better solution to that set of issues. Also add documentation around these issues, to help extension authors write secure installation scripts. Patch by me, following an observation by Andres Freund; thanks to Noah Misch for review. Security: CVE-2020-14350
2020-08-07Fix bogus EXPLAIN output for Hash AggregateDavid Rowley
9bdb300de modified the EXPLAIN output for Hash Aggregate to show details from parallel workers. However, it neglected to consider that a given parallel worker may not have assisted with the given Hash Aggregate. This can occur when workers fail to start or during Parallel Append with enable_partitionwise_join enabled when only a single worker is working on a non-parallel aware sub-plan. It could also happen if a worker simply wasn't fast enough to get any work done before other processes went and finished all the work. The bogus output came from the fact that ExplainOpenWorker() skipped showing any details for non-initialized workers but show_hashagg_info() did show details from the worker. This meant that the worker properties that were shown were not properly attributed to the worker that they belong to. In passing, we also now don't show Hash Aggregate properties for the leader process when it did not contribute any work to the Hash Aggregate. This can occur either during Parallel Append when only a parallel worker worked on a given sub plan or with parallel_leader_participation set to off. This aims to make the behavior of Hash Aggregate's EXPLAIN output more similar to Sort's. Reported-by: Justin Pryzby Discussion: https://postgr.es/m/20200805012105.GZ28072%40telsasoft.com Backpatch-through: 13, where the original breakage was introduced
2020-08-02Use int64 instead of long in incremental sort codeDavid Rowley
Windows 64bit has 4-byte long values which is not suitable for tracking disk space usage in the incremental sort code. Let's just make all these fields int64s. Author: James Coleman Discussion: https://postgr.es/m/CAApHDvpky%2BUhof8mryPf5i%3D6e6fib2dxHqBrhp0Qhu0NeBhLJw%40mail.gmail.com Backpatch-through: 13, where the incremental sort code was added
2020-07-31Fix oversight in ALTER TYPE: typmodin/typmodout must propagate to arrays.Tom Lane
If a base type supports typmods, its array type does too, with the same interpretation. Hence changes in pg_type.typmodin/typmodout must be propagated to the array type. While here, improve AlterTypeRecurse to not recurse to domains if there is nothing we'd need to change. Oversight in fe30e7ebf. Back-patch to v13 where that came in.
2020-07-29Make EXPLAIN ANALYZE of HashAgg more similar to Hash JoinDavid Rowley
There were various unnecessary differences between Hash Agg's EXPLAIN ANALYZE output and Hash Join's. Here we modify the Hash Agg output so that it's better aligned to Hash Join's. The following changes have been made: 1. Start batches counter at 1 instead of 0. 2. Always display the "Batches" property, even when we didn't spill to disk. 3. Use the text "Batches" instead of "HashAgg Batches" for text format. 4. Use the text "Memory Usage" instead of "Peak Memory Usage" for text format. 5. Include "Batches" before "Memory Usage" in both text and non-text formats. In passing also modify the "Planned Partitions" property so that we show it regardless of if the value is 0 or not for non-text EXPLAIN formats. This was pointed out by Justin Pryzby and probably should have been part of 40efbf870. Reviewed-by: Justin Pryzby, Jeff Davis Discussion: https://postgr.es/m/CAApHDvrshRnA6C0VFnu7Fb9TVvgGo80PUMm5+2DiaS1gEkPvtw@mail.gmail.com Backpatch-through: 13, where HashAgg batching was introduced
2020-07-14Fix timing issue with ALTER TABLE's validate constraintDavid Rowley
An ALTER TABLE to validate a foreign key in which another subcommand already caused a pending table rewrite could fail due to ALTER TABLE attempting to validate the foreign key before the actual table rewrite takes place. This situation could result in an error such as: ERROR: could not read block 0 in file "base/nnnnn/nnnnn": read only 0 of 8192 bytes The failure here was due to the SPI call which validates the foreign key trying to access an index which is yet to be rebuilt. Similarly, we also incorrectly tried to validate CHECK constraints before the heap had been rewritten. The fix for both is to delay constraint validation until phase 3, after the table has been rewritten. For CHECK constraints this means a slight behavioral change. Previously ALTER TABLE VALIDATE CONSTRAINT on inheritance tables would be validated from the bottom up. This was different from the order of evaluation when a new CHECK constraint was added. The changes made here aligns the VALIDATE CONSTRAINT evaluation order for inheritance tables to be the same as ADD CONSTRAINT, which is generally top-down. Reported-by: Nazli Ugur Koyluoglu, using SQLancer Discussion: https://postgr.es/m/CAApHDvp%3DZXv8wiRyk_0rWr00skhGkt8vXDrHJYXRMft3TjkxCA%40mail.gmail.com Backpatch-through: 9.5 (all supported versions)
2020-07-09Fix whitespace in HashAgg EXPLAIN ANALYZEDavid Rowley
The Sort node does not put a space between the number of kilobytes and the "kB" of memory or disk space used, but HashAgg does. Here we align HashAgg to do the same as Sort. Sort has been displaying this information for longer than HashAgg, so it makes sense to align HashAgg to Sort rather than the other way around. Reported-by: Justin Pryzby Discussion: https://postgr.es/m/20200708163021.GW4107@telsasoft.com Backpatch-through: 13, where the hashagg started showing these details
2020-07-03Fix temporary tablespaces for shared filesets some more.Tom Lane
Commit ecd9e9f0b fixed the problem in the wrong place, causing unwanted side-effects on the behavior of GetNextTempTableSpace(). Instead, let's make SharedFileSetInit() responsible for subbing in the value of MyDatabaseTableSpace when the default tablespace is called for. The convention about what is in the tempTableSpaces[] array is evidently insufficiently documented, so try to improve that. It also looks like SharedFileSetInit() is doing the wrong thing in the case where temp_tablespaces is empty. It was hard-wiring use of the pg_default tablespace, but it seems like using MyDatabaseTableSpace is more consistent with what happens for other temp files. Back-patch the reversion of PrepareTempTablespaces()'s behavior to 9.5, as ecd9e9f0b was. The changes in SharedFileSetInit() go back to v11 where that was introduced. (Note there is net zero code change before v11 from these two patch sets, so nothing to release-note.) Magnus Hagander and Tom Lane Discussion: https://postgr.es/m/CABUevExg5YEsOvqMxrjoNvb3ApVyH+9jggWGKwTDFyFCVWczGQ@mail.gmail.com
2020-07-03Fix temporary tablespaces for shared filesetsMagnus Hagander
A likely copy/paste error in 98e8b480532 from back in 2004 would cause temp tablespace to be reset to InvalidOid if temp_tablespaces was set to the same value as the primary tablespace in the database. This would cause shared filesets (such as for parallel hash joins) to ignore them, putting the temporary files in the default tablespace instead of the configured one. The bug is in the old code, but it appears to have been exposed only once we had shared filesets. Reviewed-By: Daniel Gustafsson Discussion: https://postgr.es/m/CABUevExg5YEsOvqMxrjoNvb3ApVyH+9jggWGKwTDFyFCVWczGQ@mail.gmail.com Backpatch-through: 9.5
2020-07-01Further adjustments to Hashagg EXPLAIN ANALYZE outputDavid Rowley
The "Disk Usage" and "HashAgg Batches" properties in the EXPLAIN ANALYZE output for HashAgg were previously only shown if the number of batches was greater than 0. Here we change this so that these properties are always shown for EXPLAIN ANALYZE formats other than "text". The idea here is that since the HashAgg could have spilled to disk if there had been more data or groups to aggregate, then it's relevant that we're clear in the EXPLAIN ANALYZE output when no spilling occurred in this particular execution of the given plan. For the "text" EXPLAIN format, we still hide these properties when no spilling occurs. This EXPLAIN format is designed to be easy for humans to read. To maintain the readability we have a higher threshold for which properties we display for this format. Discussion: https://postgr.es/m/CAApHDvo_dmNozQQTmN-2jGp1vT%3Ddxx7Q0vd%2BMvD1cGpv2HU%3DSg%40mail.gmail.com Backpatch-through: 13, where the hashagg spilling code was added.
2020-06-22Undo double-quoting of index names in non-text EXPLAIN output formats.Tom Lane
explain_get_index_name() applied quote_identifier() to the index name. This is fine for text output, but the non-text output formats all have their own quoting conventions and would much rather start from the actual index name. For example in JSON you'd get something like "Index Name": "\"My Index\"", which is surely not desirable, especially when the same does not happen for table names. Hence, move the responsibility for applying quoting out to the callers, where it can go into already-existing special code paths for text format. This changes the API spec for users of explain_get_index_name_hook: before, they were supposed to apply quote_identifier() if necessary, now they should not. Research suggests that the only publicly available user of the hook is hypopg, and it actually forgot to apply quoting anyway, so it's fine. (In any case, there's no behavioral change for the output of a hook as seen in non-text EXPLAIN formats, so this won't break any case that programs should be relying on.) Digging in the commit logs, it appears that quoting was included in explain_get_index_name's duties when commit 604ffd280 invented it; and that was fine at the time because we only had text output format. This should have been rethought when non-text formats were invented, but it wasn't. This is a fairly clear bug for users of non-text EXPLAIN formats, so back-patch to all supported branches. Per bug #16502 from Maciek Sakrejda. Patch by me (based on investigation by Euler Taveira); thanks to Julien Rouhaud for review. Discussion: https://postgr.es/m/16502-57bd1c9f913ed1d1@postgresql.org
2020-06-19Fix EXPLAIN ANALYZE for parallel HashAgg plansDavid Rowley
Since 1f39bce02, HashAgg nodes have had the ability to spill to disk when memory consumption exceeds work_mem. That commit added new properties to EXPLAIN ANALYZE to show the maximum memory usage and disk usage, however, it didn't quite go as far as showing that information for parallel workers. Since workers may have experienced something very different from the main process, we should show this information per worker, as is done in Sort. Reviewed-by: Justin Pryzby Reviewed-by: Jeff Davis Discussion: https://postgr.es/m/CAApHDvpEKbfZa18mM1TD7qV6PG+w97pwCWq5tVD0dX7e11gRJw@mail.gmail.com Backpatch-through: 13, where the hashagg spilling code was added.
2020-06-09Spelling adjustmentsPeter Eisentraut
similar to 0fd2a79a637f9f96b9830524823df0454e962f96
2020-06-07Spelling adjustmentsPeter Eisentraut
2020-05-28Add missing error code to "cannot attach index ..." error.Heikki Linnakangas
ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE was used in an ereport with the same message but different errdetail a few lines earlier, so use that here as well. Backpatch-through: 11
2020-05-23Add missing invocations to object access hooksMichael Paquier
The following commands have been missing calls to object access hooks InvokeObjectPost{Create|Alter}Hook normally applied to all commands: - ALTER RULE RENAME TO - ALTER USER MAPPING - CREATE ACCESS METHOD - CREATE STATISTICS Thanks also to Robert Haas for the discussion. Author: Mark Dilger Reviewed-by: Álvaro Herrera, Michael Paquier Discussion: https://postgr.es/m/435CD295-F409-44E0-91EC-DF32C7AFCD76@enterprisedb.com
2020-05-16Run pgindent with new pg_bsd_indent version 2.1.1.Tom Lane
Thomas Munro fixed a longstanding annoyance in pg_bsd_indent, that it would misformat lines containing IsA() macros on the assumption that the IsA() call should be treated like a cast. This improves some other cases involving field/variable names that match typedefs, too. The only places that get worse are a couple of uses of the OpenSSL macro STACK_OF(); we'll gladly take that trade-off. Discussion: https://postgr.es/m/20200114221814.GA19630@alvherre.pgsql
2020-05-15Rename SLRU structures and associated LWLocks.Tom Lane
Originally, the names assigned to SLRUs had no purpose other than being shmem lookup keys, so not a lot of thought went into them. As of v13, though, we're exposing them in the pg_stat_slru view and the pg_stat_reset_slru function, so it seems advisable to take a bit more care. Rename them to names based on the associated on-disk storage directories (which fortunately we *did* think about, to some extent; since those are also visible to DBAs, consistency seems like a good thing). Also rename the associated LWLocks, since those names are likewise user-exposed now as wait event names. For the most part I only touched symbols used in the respective modules' SimpleLruInit() calls, not the names of other related objects. This renaming could have been taken further, and maybe someday we will do so. But for now it seems undesirable to change the names of any globally visible functions or structs, so some inconsistency is unavoidable. (But I *did* terminate "oldserxid" with prejudice, as I found that name both unreadable and not descriptive of the SLRU's contents.) Table 27.12 needs re-alphabetization now, but I'll leave that till after the other LWLock renamings I have in mind. Discussion: https://postgr.es/m/28683.1589405363@sss.pgh.pa.us
2020-05-15Make COPY TO keep locks until the transaction end.Amit Kapila
COPY TO released the ACCESS SHARE lock immediately when it was done rather than holding on to it until the end of the transaction. This breaks the case where a REPEATABLE READ transaction could see an empty table if it repeats a COPY statement and somebody truncated the table in the meantime. Before 4dded12faad the lock was also released after COPY FROM, but the commit failed to notice the irregularity in COPY TO. This is old behavior but doesn't seem important enough to backpatch. Author: Laurenz Albe, based on suggestion by Robert Haas and Tom Lane Reviewed-by: Amit Kapila Discussion: https://postgr.es/m/7bcfc39d4176faf85ab317d0c26786953646a411.camel@cybertec.at