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2022-06-25CREATE INDEX: use the original userid for more ACL checks.Noah Misch
Commit a117cebd638dd02e5c2e791c25e43745f233111b used the original userid for ACL checks located directly in DefineIndex(), but it still adopted the table owner userid for more ACL checks than intended. That broke dump/reload of indexes that refer to an operator class, collation, or exclusion operator in a schema other than "public" or "pg_catalog". Back-patch to v10 (all supported versions), like the earlier commit. Nathan Bossart and Noah Misch Discussion: https://postgr.es/m/f8a4105f076544c180a87ef0c4822352@stmuk.bayern.de
2022-05-20Fix DDL deparse of CREATE OPERATOR CLASSAlvaro Herrera
When an implicit operator family is created, it wasn't getting reported. Make it do so. This has always been missing. Backpatch to 10. Author: Masahiko Sawada <sawada.mshk@gmail.com> Reported-by: Leslie LEMAIRE <leslie.lemaire@developpement-durable.gouv.fr> Reviewed-by: Amit Kapila <amit.kapila16@gmail.com> Reviewed-by: Michael Paquiër <michael@paquier.xyz> Discussion: https://postgr.es/m/f74d69e151b22171e8829551b1159e77@developpement-durable.gouv.fr
2022-05-09In REFRESH MATERIALIZED VIEW, set user ID before running user code.Noah Misch
It intended to, but did not, achieve this. Adopt the new standard of setting user ID just after locking the relation. Back-patch to v10 (all supported versions). Reviewed by Simon Riggs. Reported by Alvaro Herrera. Security: CVE-2022-1552
2022-05-09Make relation-enumerating operations be security-restricted operations.Noah Misch
When a feature enumerates relations and runs functions associated with all found relations, the feature's user shall not need to trust every user having permission to create objects. BRIN-specific functionality in autovacuum neglected to account for this, as did pg_amcheck and CLUSTER. 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. CREATE INDEX (not a relation-enumerating operation) and REINDEX protected themselves too late. This change extends to the non-enumerating amcheck interface. Back-patch to v10 (all supported versions). Sergey Shinderuk, reviewed (in earlier versions) by Alexander Lakhin. Reported by Alexander Lakhin. Security: CVE-2022-1552
2022-04-19Fix breakage in AlterFunction().Tom Lane
An ALTER FUNCTION command that tried to update both the function's proparallel property and its proconfig list failed to do the former, because it stored the new proparallel value into a tuple that was no longer the interesting one. Carelessness in 7aea8e4f2. (I did not bother with a regression test, because the only likely future breakage would be for someone to ignore the comment I added and add some other field update after the heap_modify_tuple step. A test using existing function properties could not catch that.) Per report from Bryn Llewellyn. Back-patch to all supported branches. Discussion: https://postgr.es/m/8AC9A37F-99BD-446F-A2F7-B89AD0022774@yugabyte.com
2022-03-30Fix typo in comment.Etsuro Fujita
2022-03-21Fix risk of deadlock failure while dropping a partitioned index.Tom Lane
DROP INDEX needs to lock the index's table before the index itself, else it will deadlock against ordinary queries that acquire the relation locks in that order. This is correctly mechanized for plain indexes by RangeVarCallbackForDropRelation; but in the case of a partitioned index, we neglected to lock the child tables in advance of locking the child indexes. We can fix that by traversing the inheritance tree and acquiring the needed locks in RemoveRelations, after we have acquired our locks on the parent partitioned table and index. While at it, do some refactoring to eliminate confusion between the actual and expected relkind in RangeVarCallbackForDropRelation. We can save a couple of syscache lookups too, by having that function pass back info that RemoveRelations will need. Back-patch to v11 where partitioned indexes were added. Jimmy Yih, Gaurab Dey, Tom Lane Discussion: https://postgr.es/m/BYAPR05MB645402330042E17D91A70C12BD5F9@BYAPR05MB6454.namprd05.prod.outlook.com
2022-01-15Build inherited extended stats on partitioned tablesTomas Vondra
Commit 859b3003de disabled building of extended stats for inheritance trees, to prevent updating the same catalog row twice. While that resolved the issue, it also means there are no extended stats for declaratively partitioned tables, because there are no data in the non-leaf relations. That also means declaratively partitioned tables were not affected by the issue 859b3003de addressed, which means this is a regression affecting queries that calculate estimates for the whole inheritance tree as a whole (which includes e.g. GROUP BY queries). But because partitioned tables are empty, we can invert the condition and build statistics only for the case with inheritance, without losing anything. And we can consider them when calculating estimates. It may be necessary to run ANALYZE on partitioned tables, to collect proper statistics. For declarative partitioning there should no prior statistics, and it might take time before autoanalyze is triggered. For tables partitioned by inheritance the statistics may include data from child relations (if built 859b3003de), contradicting the current code. Report and patch by Justin Pryzby, minor fixes and cleanup by me. Backpatch all the way back to PostgreSQL 10, where extended statistics were introduced (same as 859b3003de). Author: Justin Pryzby Reported-by: Justin Pryzby Backpatch-through: 10 Discussion: https://postgr.es/m/20210923212624.GI831%40telsasoft.com
2022-01-06Prevent altering partitioned table's rowtype, if it's used elsewhere.Tom Lane
We disallow altering a column datatype within a regular table, if the table's rowtype is used as a column type elsewhere, because we lack code to go around and rewrite the other tables. This restriction should apply to partitioned tables as well, but it was not checked because ATRewriteTables and ATPrepAlterColumnType were not on the same page about who should do it for which relkinds. Per bug #17351 from Alexander Lakhin. Back-patch to all supported branches. Discussion: https://postgr.es/m/17351-6db1870f3f4f612a@postgresql.org
2022-01-03Fix index-only scan plans, take 2.Tom Lane
Commit 4ace45677 failed to fix the problem fully, because the same issue of attempting to fetch a non-returnable index column can occur when rechecking the indexqual after using a lossy index operator. Moreover, it broke EXPLAIN for such indexquals (which indicates a gap in our test cases :-(). Revert the code changes of 4ace45677 in favor of adding a new field to struct IndexOnlyScan, containing a version of the indexqual that can be executed against the index-returned tuple without using any non-returnable columns. (The restrictions imposed by check_index_only guarantee this is possible, although we may have to recompute indexed expressions.) Support construction of that during setrefs.c processing by marking IndexOnlyScan.indextlist entries as resjunk if they can't be returned, rather than removing them entirely. (We could alternatively require setrefs.c to look up the IndexOptInfo again, but abusing resjunk this way seems like a reasonably safe way to avoid needing to do that.) This solution isn't great from an API-stability standpoint: if there are any extensions out there that build IndexOnlyScan structs directly, they'll be broken in the next minor releases. However, only a very invasive extension would be likely to do such a thing. There's no change in the Path representation, so typical planner extensions shouldn't have a problem. As before, back-patch to all supported branches. Discussion: https://postgr.es/m/3179992.1641150853@sss.pgh.pa.us Discussion: https://postgr.es/m/17350-b5bdcf476e5badbb@postgresql.org
2021-11-25Block ALTER TABLE .. DROP NOT NULL on columns in replica identity indexMichael Paquier
Replica identities that depend directly on an index rely on a set of properties, one of them being that all the columns defined in this index have to be marked as NOT NULL. There was a hole in the logic with ALTER TABLE DROP NOT NULL, where it was possible to remove the NOT NULL property of a column part of an index used as replica identity, so block it to avoid problems with logical decoding down the road. The same check was already done columns part of a primary key, so the fix is straight-forward. Author: Haiying Tang, Hou Zhijie Reviewed-by: Dilip Kumar, Michael Paquier Discussion: https://postgr.es/m/OS0PR01MB6113338C102BEE8B2FFC5BD9FB619@OS0PR01MB6113.jpnprd01.prod.outlook.com Backpatch-through: 10
2021-11-16Invalidate relcache when changing REPLICA IDENTITY index.Amit Kapila
When changing REPLICA IDENTITY INDEX to another one, the target table's relcache was not being invalidated. This leads to skipping update/delete operations during apply on the subscriber side as the columns required to search corresponding rows won't get logged. Author: Tang Haiying, Hou Zhijie Reviewed-by: Euler Taveira, Amit Kapila Backpatch-through: 10 Discussion: https://postgr.es/m/OS0PR01MB61133CA11630DAE45BC6AD95FB939@OS0PR01MB6113.jpnprd01.prod.outlook.com
2021-10-19Ensure correct lock level is used in ALTER ... RENAMEAlvaro Herrera
Commit 1b5d797cd4f7 intended to relax the lock level used to rename indexes, but inadvertently allowed *any* relation to be renamed with a lowered lock level, as long as the command is spelled ALTER INDEX. That's undesirable for other relation types, so retry the operation with the higher lock if the relation turns out not to be an index. After this fix, ALTER INDEX <sometable> RENAME will require access exclusive lock, which it didn't before. Author: Nathan Bossart <bossartn@amazon.com> Author: Álvaro Herrera <alvherre@alvh.no-ip.org> Reported-by: Onder Kalaci <onderk@microsoft.com> Discussion: https://postgr.es/m/PH0PR21MB1328189E2821CDEC646F8178D8AE9@PH0PR21MB1328.namprd21.prod.outlook.com
2021-10-18Invalidate partitions of table being attached/detachedAlvaro Herrera
Failing to do that, any direct inserts/updates of those partitions would fail to enforce the correct constraint, that is, one that considers the new partition constraint of their parent table. Backpatch to 10. Reported by: Hou Zhijie <houzj.fnst@fujitsu.com> Author: Amit Langote <amitlangote09@gmail.com> Author: Álvaro Herrera <alvherre@alvh.no-ip.org> Reviewed-by: Nitin Jadhav <nitinjadhavpostgres@gmail.com> Reviewed-by: Pavel Borisov <pashkin.elfe@gmail.com> Discussion: https://postgr.es/m/OS3PR01MB5718DA1C4609A25186D1FBF194089%40OS3PR01MB5718.jpnprd01.prod.outlook.com
2021-10-14Check criticalSharedRelcachesBuilt in GetSharedSecurityLabel().Jeff Davis
An extension may want to call GetSecurityLabel() on a shared object before the shared relcaches are fully initialized. For instance, a ClientAuthentication_hook might want to retrieve the security label on a role. Discussion: https://postgr.es/m/ecb7af0b26e3be1d96d291c8453a86f1f82d9061.camel@j-davis.com Backpatch-through: 9.6
2021-09-21Fix misevaluation of STABLE parameters in CALL within plpgsql.Tom Lane
Before commit 84f5c2908, a STABLE function in a plpgsql CALL statement's argument list would see an up-to-date snapshot, because exec_stmt_call would push a new snapshot. I got rid of that because the possibility of the snapshot disappearing within COMMIT made it too hard to manage a snapshot across the CALL statement. That's fine so far as the procedure itself goes, but I forgot to think about the possibility of STABLE functions within the CALL argument list. As things now stand, those'll be executed with the Portal's snapshot as ActiveSnapshot, keeping them from seeing updates more recent than Portal startup. (VOLATILE functions don't have a problem because they take their own snapshots; which indeed is also why the procedure itself doesn't have a problem. There are no STABLE procedures.) We can fix this by pushing a new snapshot transiently within ExecuteCallStmt itself. Popping the snapshot before we get into the procedure proper eliminates the management problem. The possibly-useless extra snapshot-grab is slightly annoying, but it's no worse than what happened before 84f5c2908. Per bug #17199 from Alexander Nawratil. Back-patch to v11, like the previous patch. Discussion: https://postgr.es/m/17199-1ab2561f0d94af92@postgresql.org
2021-09-10Fix some anomalies with NO SCROLL cursors.Tom Lane
We have long forbidden fetching backwards from a NO SCROLL cursor, but the prohibition didn't extend to cases in which we rewind the query altogether and then re-fetch forwards. I think the reason is that this logic was mainly meant to protect plan nodes that can't be run in the reverse direction. However, re-reading the query output is problematic if the query is volatile (which includes SELECT FOR UPDATE, not just queries with volatile functions): the re-read can produce different results, which confuses the cursor navigation logic completely. Another reason for disliking this approach is that some code paths will either fetch backwards or rewind-and-fetch-forwards depending on the distance to the target row; so that seemingly identical use-cases may or may not draw the "cursor can only scan forward" error. Hence, let's clean things up by disallowing rewind as well as fetch-backwards in a NO SCROLL cursor. Ordinarily we'd only make such a definitional change in HEAD, but there is a third reason to consider this change now. Commit ba2c6d6ce created some new user-visible anomalies for non-scrollable cursors WITH HOLD, in that navigation in the cursor result got confused if the cursor had been partially read before committing. The only good way to resolve those anomalies is to forbid rewinding such a cursor, which allows removal of the incorrect cursor state manipulations that ba2c6d6ce added to PersistHoldablePortal. To minimize the behavioral change in the back branches (including v14), refuse to rewind a NO SCROLL cursor only when it has a holdStore, ie has been held over from a previous transaction due to WITH HOLD. This should avoid breaking most applications that have been sloppy about whether to declare cursors as scrollable. We'll enforce the prohibition across-the-board beginning in v15. Back-patch to v11, as ba2c6d6ce was. Discussion: https://postgr.es/m/3712911.1631207435@sss.pgh.pa.us
2021-09-09Avoid fetching from an already-terminated plan.Tom Lane
Some plan node types don't react well to being called again after they've already returned NULL. PortalRunSelect() has long dealt with this by calling the executor with NoMovementScanDirection if it sees that we've already run the portal to the end. However, commit ba2c6d6ce overlooked this point, so that persisting an already-fully-fetched cursor would fail if it had such a plan. Per report from Tomas Barton. Back-patch to v11, as the faulty commit was. (I've omitted a test case because the type of plan that causes a problem isn't all that stable.) Discussion: https://postgr.es/m/CAPV2KRjd=ErgVGbvO2Ty20tKTEZZr6cYsYLxgN_W3eAo9pf5sw@mail.gmail.com
2021-09-08Invalidate relcache for publications defined for all tables.Amit Kapila
Updates/Deletes on a relation were allowed even without replica identity after we define the publication for all tables. This would later lead to an error on subscribers. The reason was that for such publications we were not invalidating the relcache and the publication information for relations was not getting rebuilt. Similarly, we were not invalidating the relcache after dropping of such publications which will prohibit Updates/Deletes without replica identity even without any publication. Author: Vignesh C and Hou Zhijie Reviewed-by: Hou Zhijie, Kyotaro Horiguchi, Amit Kapila Backpatch-through: 10, where it was introduced Discussion: https://postgr.es/m/CALDaNm0pF6zeWqCA8TCe2sDuwFAy8fCqba=nHampCKag-qLixg@mail.gmail.com
2021-09-03Disallow creating an ICU collation if the DB encoding won't support it.Tom Lane
Previously this was allowed, but the collation effectively vanished into the ether because of the way lookup_collation() works: you could not use the collation, nor even drop it. Seems better to give an error up front than to leave the user wondering why it doesn't work. (Because this test is in DefineCollation not CreateCollation, it does not prevent pg_import_system_collations from creating ICU collations, regardless of the initially-chosen encoding.) Per bug #17170 from Andrew Bille. Back-patch to v10 where ICU support was added. Discussion: https://postgr.es/m/17170-95845cf3f0a9c36d@postgresql.org
2021-08-27Fix data loss in wal_level=minimal crash recovery of CREATE TABLESPACE.Noah Misch
If the system crashed between CREATE TABLESPACE and the next checkpoint, the result could be some files in the tablespace unexpectedly containing no rows. Affected files would be those for which the system did not write WAL; see the wal_skip_threshold documentation. Before v13, a different set of conditions governed the writing of WAL; see v12's <sect2 id="populate-pitr">. (The v12 conditions were broader in some ways and narrower in others.) Users may want to audit non-default tablespaces for unexpected short files. The bug could have truncated an index without affecting the associated table, and reindexing the index would fix that particular problem. This fixes the bug by making create_tablespace_directories() more like TablespaceCreateDbspace(). create_tablespace_directories() was recursively removing tablespace contents, reasoning that WAL redo would recreate everything removed that way. That assumption holds for other wal_level values. Under wal_level=minimal, the old approach could delete files for which no other copy existed. Back-patch to 9.6 (all supported versions). Reviewed by Robert Haas and Prabhat Sahu. Reported by Robert Haas. Discussion: https://postgr.es/m/CA+TgmoaLO9ncuwvr2nN-J4VEP5XyAcy=zKiHxQzBbFRxxGxm0w@mail.gmail.com
2021-08-25Fix toast rewrites in logical decoding.Amit Kapila
Commit 325f2ec555 introduced pg_class.relwrite to skip operations on tables created as part of a heap rewrite during DDL. It links such transient heaps to the original relation OID via this new field in pg_class but forgot to do anything about toast tables. So, logical decoding was not able to skip operations on internally created toast tables. This leads to an error when we tried to decode the WAL for the next operation for which it appeared that there is a toast data where actually it didn't have any toast data. To fix this, we set pg_class.relwrite for internally created toast tables as well which allowed skipping operations on them during logical decoding. Author: Bertrand Drouvot Reviewed-by: David Zhang, Amit Kapila Backpatch-through: 11, where it was introduced Discussion: https://postgr.es/m/b5146fb1-ad9e-7d6e-f980-98ed68744a7c@amazon.com
2021-08-07Really fix the ambiguity in REFRESH MATERIALIZED VIEW CONCURRENTLY.Tom Lane
Rather than trying to pick table aliases that won't conflict with any possible user-defined matview column name, adjust the queries' syntax so that the aliases are only used in places where they can't be mistaken for column names. Mostly this consists of writing "alias.*" not just "alias", which adds clarity for humans as well as machines. We do have the issue that "SELECT alias.*" acts differently from "SELECT alias", but we can use the same hack ruleutils.c uses for whole-row variables in SELECT lists: write "alias.*::compositetype". We might as well revert to the original aliases after doing this; they're a bit easier to read. Like 75d66d10e, back-patch to all supported branches. Discussion: https://postgr.es/m/2488325.1628261320@sss.pgh.pa.us
2021-07-19Don't allow to set replication slot_name as ''.Amit Kapila
We don't allow to create replication slot_name as an empty string ('') via SQL API pg_create_logical_replication_slot() but it is allowed to be set via Alter Subscription command. This will lead to apply worker repeatedly keep trying to stream data via slot_name '' and the user is not allowed to create the slot with that name. Author: Japin Li Reviewed-By: Ranier Vilela, Amit Kapila Backpatch-through: 10, where it was introduced Discussion: https://postgr.es/m/MEYP282MB1669CBD98E721C77CA696499B61A9@MEYP282MB1669.AUSP282.PROD.OUTLOOK.COM
2021-07-16Preserve firing-on state when cloning row triggers to partitionsAlvaro Herrera
When triggers are cloned from partitioned tables to their partitions, the 'tgenabled' flag (origin/replica/always/disable) was not propagated. Make it so that the flag on the trigger on partition is initially set to the same value as on the partitioned table. Add a test case to verify the behavior. Backpatch to 11, where this appeared in commit 86f575948c77. Author: Álvaro Herrera <alvherre@alvh.no-ip.org> Reported-by: Justin Pryzby <pryzby@telsasoft.com> Discussion: https://postgr.es/m/20200930223450.GA14848@telsasoft.com
2021-07-14Fix unexpected error messages for various flavors of ALTER TABLEMichael Paquier
Some commands of ALTER TABLE could fail with the following error: ERROR: "tab" is of the wrong type This error is unexpected, as all the code paths leading to ATWrongRelkindError() should use a supported set of relkinds to generate correct error messages. This commit closes the gap with such mistakes, by adding all the missing relkind combinations. Tests are added to check all the problems found. Note that some combinations are not used, but these are left around as it could have an impact on applications relying on this code. 2ed532e has done a much larger refactoring on HEAD to make such error messages easier to manage in the long-term, so nothing is needed there. Author: Kyotaro Horiguchi Reviewed-by: Peter Eisentraut, Ahsan Hadi, Michael Paquier Discussion: https://postgr.es/m/20210216.181415.368926598204753659.horikyota.ntt@gmail.com Backpatch-through: 11
2021-07-11Lock the extension during ALTER EXTENSION ADD/DROP.Tom Lane
Although we were careful to lock the object being added or dropped, we failed to get any sort of lock on the extension itself. This allowed the ALTER to proceed in parallel with a DROP EXTENSION, which is problematic for a couple of reasons. If both commands succeeded we'd be left with a dangling link in pg_depend, which would cause problems later. Also, if the ALTER failed for some reason, it might try to print the extension's name, and that could result in a crash or (in older branches) a silly error message complaining about extension "(null)". Per bug #17098 from Alexander Lakhin. Back-patch to all supported branches. Discussion: https://postgr.es/m/17098-b960f3616c861f83@postgresql.org
2021-06-25Remove unnecessary failure cases in RemoveRoleFromObjectPolicy().Tom Lane
It's not really necessary for this function to open or lock the relation associated with the pg_policy entry it's modifying. The error checks it's making on the rel are if anything counterproductive (e.g., if we don't want to allow installation of policies on system catalogs, here is not the place to prevent that). In particular, it seems just wrong to insist on an ownership check. That has the net effect of forcing people to use superuser for DROP OWNED BY, which surely is not an effect we want. Also there is no point in rebuilding the dependencies of the policy expressions, which aren't being changed. Lastly, locking the table also seems counterproductive; it's not helping to prevent race conditions, since we failed to re-read the pg_policy row after acquiring the lock. That means that concurrent DDL would likely result in "tuple concurrently updated/deleted" errors; which is the same behavior this code will produce, with less overhead. Per discussion of bug #17062. Back-patch to all supported versions, as the failure cases this eliminates seem just as undesirable in 9.6 as in HEAD. Discussion: https://postgr.es/m/1573181.1624220108@sss.pgh.pa.us
2021-06-18Fix misbehavior of DROP OWNED BY with duplicate polroles entries.Tom Lane
Ordinarily, a pg_policy.polroles array wouldn't list the same role more than once; but CREATE POLICY does not prevent that. If we perform DROP OWNED BY on a role that is listed more than once, RemoveRoleFromObjectPolicy either suffered an assertion failure or encountered a tuple-updated-by-self error. Rewrite it to cope correctly with duplicate entries, and add a CommandCounterIncrement call to prevent the other problem. Per discussion, there's other cleanup that ought to happen here, but this seems like the minimum essential fix. Per bug #17062 from Alexander Lakhin. It's been broken all along, so back-patch to all supported branches. Discussion: https://postgr.es/m/17062-11f471ae3199ca23@postgresql.org
2021-06-18Avoid scribbling on input node tree in CREATE/ALTER DOMAIN.Tom Lane
This works fine in the "simple Query" code path; but if the statement is in the plan cache then it's corrupted for future re-execution. Apply copyObject() to protect the original tree from modification, as we've done elsewhere. This narrow fix is applied only to the back branches. In HEAD, the problem was fixed more generally by commit 7c337b6b5; but that changed ProcessUtility's API, so it's infeasible to back-patch. Per bug #17053 from Charles Samborski. Discussion: https://postgr.es/m/931771.1623893989@sss.pgh.pa.us Discussion: https://postgr.es/m/17053-3ca3f501bbc212b4@postgresql.org
2021-06-18Don't set a fast default for anything but a plain tableAndrew Dunstan
The fast default code added in Release 11 omitted to check that the table a fast default was being added to was a plain table. Thus one could be added to a foreign table, which predicably blows up. Here we perform that check. In addition, on the back branches, since some of these might have escaped into the wild, if we encounter a missing value for an attribute of something other than a plain table we ignore it. Fixes bug #17056 Backpatch to release 11, Reviewed by: Andres Freund, Álvaro Herrera and Tom Lane
2021-06-16Fix plancache refcount leak after error in ExecuteQuery.Tom Lane
When stuffing a plan from the plancache into a Portal, one is not supposed to risk throwing an error between GetCachedPlan and PortalDefineQuery; if that happens, the plan refcount incremented by GetCachedPlan will be leaked. I managed to break this rule while refactoring code in 9dbf2b7d7. There is no visible consequence other than some memory leakage, and since nobody is very likely to trigger the relevant error conditions many times in a row, it's not surprising we haven't noticed. Nonetheless, it's a bug, so rearrange the order of operations to remove the hazard. Noted on the way to looking for a better fix for bug #17053. This mistake is pretty old, so back-patch to all supported branches.
2021-06-08Avoid misbehavior when persisting a non-stable cursor.Tom Lane
PersistHoldablePortal has long assumed that it should store the entire output of the query-to-be-persisted, which requires rewinding and re-reading the output. This is problematic if the query is not stable: we might get different row contents, or even a different number of rows, which'd confuse the cursor state mightily. In the case where the cursor is NO SCROLL, this is very easy to solve: just store the remaining query output, without any rewinding, and tweak the portal's cursor state to match. Aside from removing the semantic problem, this could be significantly more efficient than storing the whole output. If the cursor is scrollable, there's not much we can do, but it was already the case that scrolling a volatile query's result was pretty unsafe. We can just document more clearly that getting correct results from that is not guaranteed. There are already prohibitions in place on using SCROLL with FOR UPDATE/SHARE, which is one way for a SELECT query to have non-stable results. We could imagine prohibiting SCROLL when the query contains volatile functions, but that would be expensive to enforce. Moreover, it could break applications that work just fine, if they have functions that are in fact stable but the user neglected to mark them so. So settle for documenting the hazard. While this problem has existed in some guise for a long time, it got a lot worse in v11, which introduced the possibility of persisting plpgsql cursors (perhaps implicit ones) even when they violate the rules for what can be marked WITH HOLD. Hence, I've chosen to back-patch to v11 but not further. Per bug #17050 from Алексей Булгаков. Discussion: https://postgr.es/m/17050-f77aa827dc85247c@postgresql.org
2021-06-03Reduce risks of conflicts in internal queries of REFRESH MATVIEW CONCURRENTLYMichael Paquier
The internal SQL queries used by REFRESH MATERIALIZED VIEW CONCURRENTLY include some aliases for its diff and temporary relations with rather-generic names: diff, newdata, newdata2 and mv. Depending on the queries used for the materialized view, using CONCURRENTLY could lead to some internal failures if the query and those internal aliases conflict. Those names have been chosen in 841c29c8. This commit switches instead to a naming pattern which is less likely going to cause conflicts, based on an idea from Thomas Munro, by appending _$ to those aliases. This is not perfect as those new names could still conflict, but at least it has the advantage to keep the code readable and simple while reducing the likelihood of conflicts to be close to zero. Reported-by: Mathis Rudolf Author: Bharath Rupireddy Reviewed-by: Bernd Helmle, Thomas Munro, Michael Paquier Discussion: https://postgr.es/m/109c267a-10d2-3c53-b60e-720fcf44d9e8@credativ.de Backpatch-through: 9.6
2021-05-21Fix usage of "tableoid" in GENERATED expressions.Tom Lane
We consider this supported (though I've got my doubts that it's a good idea, because tableoid is not immutable). However, several code paths failed to fill the field in soon enough, causing such a GENERATED expression to see zero or the wrong value. This occurred when ALTER TABLE adds a new GENERATED column to a table with existing rows, and during regular INSERT or UPDATE on a foreign table with GENERATED columns. Noted during investigation of a report from Vitaly Ustinov. Back-patch to v12 where GENERATED came in. Discussion: https://postgr.es/m/CAM_DEiWR2DPT6U4xb-Ehigozzd3n3G37ZB1+867zbsEVtYoJww@mail.gmail.com
2021-05-21Restore the portal-level snapshot after procedure COMMIT/ROLLBACK.Tom Lane
COMMIT/ROLLBACK necessarily destroys all snapshots within the session. The original implementation of intra-procedure transactions just cavalierly did that, ignoring the fact that this left us executing in a rather different environment than normal. In particular, it turns out that handling of toasted datums depends rather critically on there being an outer ActiveSnapshot: otherwise, when SPI or the core executor pop whatever snapshot they used and return, it's unsafe to dereference any toasted datums that may appear in the query result. It's possible to demonstrate "no known snapshots" and "missing chunk number N for toast value" errors as a result of this oversight. Historically this outer snapshot has been held by the Portal code, and that seems like a good plan to preserve. So add infrastructure to pquery.c to allow re-establishing the Portal-owned snapshot if it's not there anymore, and add enough bookkeeping support that we can tell whether it is or not. We can't, however, just re-establish the Portal snapshot as part of COMMIT/ROLLBACK. As in normal transaction start, acquiring the first snapshot should wait until after SET and LOCK commands. Hence, teach spi.c about doing this at the right time. (Note that this patch doesn't fix the problem for any PLs that try to run intra-procedure transactions without using SPI to execute SQL commands.) This makes SPI's no_snapshots parameter rather a misnomer, so in HEAD, rename that to allow_nonatomic. replication/logical/worker.c also needs some fixes, because it wasn't careful to hold a snapshot open around AFTER trigger execution. That code doesn't use a Portal, which I suspect someday we're gonna have to fix. But for now, just rearrange the order of operations. This includes back-patching the recent addition of finish_estate() to centralize the cleanup logic there. This also back-patches commit 2ecfeda3e into v13, to improve the test coverage for worker.c (it was that test that exposed that worker.c's snapshot management is wrong). Per bug #15990 from Andreas Wicht. Back-patch to v11 where intra-procedure COMMIT was added. Discussion: https://postgr.es/m/15990-eee2ac466b11293d@postgresql.org
2021-05-07AlterSubscription_refresh: avoid stomping on global variableAlvaro Herrera
This patch replaces use of the global "wrconn" variable in AlterSubscription_refresh with a local variable of the same name, making it consistent with other functions in subscriptioncmds.c (e.g. DropSubscription). The global wrconn is only meant to be used for logical apply/tablesync worker. Abusing it this way is known to cause trouble if an apply worker manages to do a subscription refresh, such as reported by Jeremy Finzel and diagnosed by Andres Freund back in November 2020, at https://www.postgresql.org/message-id/20201111215820.qihhrz7fayu6myfi@alap3.anarazel.de Backpatch to 10. In branch master, also move the connection establishment to occur outside the PG_TRY block; this way we can remove a test for NULL in PG_FINALLY, and it also makes the code more consistent with similar code in the same file. Author: Peter Smith <peter.b.smith@fujitsu.com> Reviewed-by: Bharath Rupireddy <bharath.rupireddyforpostgres@gmail.com> Reviewed-by: Japin Li <japinli@hotmail.com> Discussion: https://postgr.es/m/CAHut+Pu7Jv9L2BOEx_Z0UtJxfDevQSAUW2mJqWU+CtmDrEZVAg@mail.gmail.com
2021-05-05Have ALTER CONSTRAINT recurse on partitioned tablesAlvaro Herrera
When ALTER TABLE .. ALTER CONSTRAINT changes deferrability properties changed in a partitioned table, we failed to propagate those changes correctly to partitions and to triggers. Repair by adding a recursion mechanism to affect all derived constraints and all derived triggers. (In particular, recurse to partitions even if their respective parents are already in the desired state: it is possible for the partitions to have been altered individually.) Because foreign keys involve tables in two sides, we cannot use the standard ALTER TABLE recursion mechanism, so we invent our own by following pg_constraint.conparentid down. When ALTER TABLE .. ALTER CONSTRAINT is invoked on the derived pg_constraint object that's automaticaly created in a partition as a result of a constraint added to its parent, raise an error instead of pretending to work and then failing to modify all the affected triggers. Before this commit such a command would be allowed but failed to affect all triggers, so it would silently misbehave. (Restoring dumps of existing databases is not affected, because pg_dump does not produce anything for such a derived constraint anyway.) Add some tests for the case. Backpatch to 11, where foreign key support was added to partitioned tables by commit 3de241dba86f. (A related change is commit f56f8f8da6af in pg12 which added support for FKs *referencing* partitioned tables; this is what forces us to use an ad-hoc recursion mechanism for this.) Diagnosed by Tom Lane from bug report from Ron L Johnson. As of this writing, no reviews were offered. Discussion: https://postgr.es/m/75fe0761-a291-86a9-c8d8-4906da077469@gmail.com Discussion: https://postgr.es/m/3144850.1607369633@sss.pgh.pa.us
2021-05-04Fix OID passed to object-alter hook during ALTER CONSTRAINTAlvaro Herrera
The OID of the constraint is used instead of the OID of the trigger -- an easy mistake to make. Apparently the object-alter hooks are not very well tested :-( Backpatch to 12, where this typo was introduced by 578b229718e8 Discussion: https://postgr.es/m/20210503231633.GA6994@alvherre.pgsql
2021-05-04Fix ALTER TABLE / INHERIT with generated columnsPeter Eisentraut
When running ALTER TABLE t2 INHERIT t1, we must check that columns in t2 that correspond to a generated column in t1 are also generated and have the same generation expression. Otherwise, this would allow creating setups that a normal CREATE TABLE sequence would not allow. Discussion: https://www.postgresql.org/message-id/22de27f6-7096-8d96-4619-7b882932ca25@2ndquadrant.com
2021-04-13Fix some inappropriately-disallowed uses of ALTER ROLE/DATABASE SET.Tom Lane
Most GUC check hooks that inspect database state have special checks that prevent them from throwing hard errors for state-dependent issues when source == PGC_S_TEST. This allows, for example, "ALTER DATABASE d SET default_text_search_config = foo" when the "foo" configuration hasn't been created yet. Without this, we have problems during dump/reload or pg_upgrade, because pg_dump has no idea about possible dependencies of GUC values and can't ensure a safe restore ordering. However, check_role() and check_session_authorization() hadn't gotten the memo about that, and would throw hard errors anyway. It's not entirely clear what is the use-case for "ALTER ROLE x SET role = y", but we've now heard two independent complaints about that bollixing an upgrade, so apparently some people are doing it. Hence, fix these two functions to act more like other check hooks with similar needs. (But I did not change their insistence on being inside a transaction, as it's still not apparent that setting either GUC from the configuration file would be wise.) Also fix check_temp_buffers, which had a different form of the disease of making state-dependent checks without any exception for PGC_S_TEST. A cursory survey of other GUC check hooks did not find any more issues of this ilk. (There are a lot of interdependencies among PGC_POSTMASTER and PGC_SIGHUP GUCs, which may be a bad idea, but they're not relevant to the immediate concern because they can't be set via ALTER ROLE/DATABASE.) Per reports from Charlie Hornsby and Nathan Bossart. Back-patch to all supported branches. Discussion: https://postgr.es/m/HE1P189MB0523B31598B0C772C908088DB7709@HE1P189MB0523.EURP189.PROD.OUTLOOK.COM Discussion: https://postgr.es/m/20160711223641.1426.86096@wrigleys.postgresql.org
2021-03-25Remove StoreSingleInheritance reimplementationAlvaro Herrera
I introduced this duplicate code in commit 8b08f7d4820f for no good reason. Remove it, and backpatch to 11 where it was introduced. Author: Álvaro Herrera <alvherre@alvh.no-ip.org>
2021-03-08Validate the OID argument of pg_import_system_collations().Tom Lane
"SELECT pg_import_system_collations(0)" caused an assertion failure. With a random nonzero argument --- or indeed with zero, in non-assert builds --- it would happily make pg_collation entries with garbage values of collnamespace. These are harmless as far as I can tell (unless maybe the OID happens to become used for a schema, later on?). In any case this isn't a security issue, since the function is superuser-only. But it seems like a gotcha for unwary DBAs, so let's add a check that the given OID belongs to some schema. Back-patch to v10 where this function was introduced.
2021-02-27Fix use-after-free bug with AfterTriggersTableData.storeslotAlvaro Herrera
AfterTriggerSaveEvent() wrongly allocates the slot in execution-span memory context, whereas the correct thing is to allocate it in a transaction-span context, because that's where the enclosing AfterTriggersTableData instance belongs into. Backpatch to 12 (the test back to 11, where it works well with no code changes, and it's good to have to confirm that the case was previously well supported); this bug seems introduced by commit ff11e7f4b9ae. Reported-by: Bertrand Drouvot <bdrouvot@amazon.com> Author: Amit Langote <amitlangote09@gmail.com> Discussion: https://postgr.es/m/39a71864-b120-5a5c-8cc5-c632b6f16761@amazon.com
2021-02-08Fix permission checks on constraint violation errors on partitions.Heikki Linnakangas
If a cross-partition UPDATE violates a constraint on the target partition, and the columns in the new partition are in different physical order than in the parent, the error message can reveal columns that the user does not have SELECT permission on. A similar bug was fixed earlier in commit 804b6b6db4. The cause of the bug is that the callers of the ExecBuildSlotValueDescription() function got confused when constructing the list of modified columns. If the tuple was routed from a parent, we converted the tuple to the parent's format, but the list of modified columns was grabbed directly from the child's RTE entry. ExecUpdateLockMode() had a similar issue. That lead to confusion on which columns are key columns, leading to wrong tuple lock being taken on tables referenced by foreign keys, when a row is updated with INSERT ON CONFLICT UPDATE. A new isolation test is added for that corner case. With this patch, the ri_RangeTableIndex field is no longer set for partitions that don't have an entry in the range table. Previously, it was set to the RTE entry of the parent relation, but that was confusing. NOTE: This modifies the ResultRelInfo struct, replacing the ri_PartitionRoot field with ri_RootResultRelInfo. That's a bit risky to backpatch, because it breaks any extensions accessing the field. The change that ri_RangeTableIndex is not set for partitions could potentially break extensions, too. The ResultRelInfos are visible to FDWs at least, and this patch required small changes to postgres_fdw. Nevertheless, this seem like the least bad option. I don't think these fields widely used in extensions; I don't think there are FDWs out there that uses the FDW "direct update" API, other than postgres_fdw. If there is, you will get a compilation error, so hopefully it is caught quickly. Backpatch to 11, where support for both cross-partition UPDATEs, and unique indexes on partitioned tables, were added. Reviewed-by: Amit Langote Security: CVE-2021-3393
2021-02-05Fix backslash-escaping multibyte chars in COPY FROM.Heikki Linnakangas
If a multi-byte character is escaped with a backslash in TEXT mode input, and the encoding is one of the client-only encodings where the bytes after the first one can have an ASCII byte "embedded" in the char, we didn't skip the character correctly. After a backslash, we only skipped the first byte of the next character, so if it was a multi-byte character, we would try to process its second byte as if it was a separate character. If it was one of the characters with special meaning, like '\n', '\r', or another '\\', that would cause trouble. One such exmple is the byte sequence '\x5ca45c2e666f6f' in Big5 encoding. That's supposed to be [backslash][two-byte character][.][f][o][o], but because the second byte of the two-byte character is 0x5c, we incorrectly treat it as another backslash. And because the next character is a dot, we parse it as end-of-copy marker, and throw an "end-of-copy marker corrupt" error. Backpatch to all supported versions. Reviewed-by: John Naylor, Kyotaro Horiguchi Discussion: https://www.postgresql.org/message-id/a897f84f-8dca-8798-3139-07da5bb38728%40iki.fi
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