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* Improved version of patch to protect pg_get_expr() against misuse:Tom Lane2010-07-30
| | | | | | | | | | look through join alias Vars to avoid breaking join queries, and move the test to someplace where it will catch more possible ways of calling a function. We still ought to throw away the whole thing in favor of a data-type-based solution, but that's not feasible in the back branches. Completion of back-port of my patch of yesterday.
* Fix another longstanding problem in copy_relation_data: it was blithelyTom Lane2010-07-29
| | | | | | | | | | | assuming that a local char[] array would be aligned on at least a word boundary. There are architectures on which that is pretty much guaranteed to NOT be the case ... and those arches also don't like non-aligned memory accesses, meaning that log_newpage() would crash if it ever got invoked. Even on Intel-ish machines there's a potential for a large performance penalty from doing I/O to an inadequately aligned buffer. So palloc it instead. Backpatch to 8.0 --- 7.4 doesn't have this code.
* Fix possible page corruption by ALTER TABLE .. SET TABLESPACE.Robert Haas2010-07-29
| | | | | | | | | | | | | | If a zeroed page is present in the heap, ALTER TABLE .. SET TABLESPACE will set the LSN and TLI while copying it, which is wrong, and heap_xlog_newpage() will do the same thing during replay, so the corruption propagates to any standby. Note, however, that the bug can't be demonstrated unless archiving is enabled, since in that case we skip WAL logging altogether, and the LSN/TLI are not set. Back-patch to 8.0; prior releases do not have tablespaces. Analysis and patch by Jeff Davis. Adjustments for back-branches and minor wordsmithing by me.
* Fix potential failure when hashing the output of a subplan that producesTom Lane2010-07-28
| | | | | | | | | | | | | | | a pass-by-reference datatype with a nontrivial projection step. We were using the same memory context for the projection operation as for the temporary context used by the hashtable routines in execGrouping.c. However, the hashtable routines feel free to reset their temp context at any time, which'd lead to destroying input data that was still needed. Report and diagnosis by Tao Ma. Back-patch to 8.1, where the problem was introduced by the changes that allowed us to work with "virtual" tuples instead of materializing intermediate tuple values everywhere. The earlier code looks quite similar, but it doesn't suffer the problem because the data gets copied into another context as a result of having to materialize ExecProject's output tuple.
* Avoid deep recursion when assigning XIDs to multiple levels of subxacts.Robert Haas2010-07-23
| | | | | | Backpatch to 8.0. Andres Freund, with cleanup and adjustment for older branches by me.
* Oops, in the previous fix to prevent a cursor that's being used in a FORHeikki Linnakangas2010-07-13
| | | | | | | | | loop from being dropped, I missed subtransaction cleanup. Pinned portals must be dropped at subtransaction cleanup just as they are at main transaction cleanup. Per bug #5556 by Robert Walker. Backpatch to 8.0, 7.4 didn't have subtransactions.
* Avoid an Assert failure in deconstruct_array() by making get_attstatsslot()Tom Lane2010-07-09
| | | | | | | | | | | | | | | | use the actual element type of the array it's disassembling, rather than trusting the type OID passed in by its caller. This is needed because sometimes the planner passes in a type OID that's only binary-compatible with the target column's type, rather than being an exact match. Per an example from Bernd Helmle. Possibly we should refactor get_attstatsslot/free_attstatsslot to not expect the caller to supply type ID data at all, but for now I'll just do the minimum-change fix. Back-patch to 7.4. Bernd's test case only crashes back to 8.0, but since these subroutines are the same in 7.4, I suspect there may be variant cases that would crash 7.4 as well.
* Fix "cannot handle unplanned sub-select" error that can occur when aTom Lane2010-07-08
| | | | | | | | | sub-select contains a join alias reference that expands into an expression containing another sub-select. Per yesterday's report from Merlin Moncure and subsequent off-list investigation. Back-patch to 7.4. Older versions didn't attempt to flatten sub-selects in ways that would trigger this problem.
* The previous fix in CVS HEAD and 8.4 for handling the case where a cursorHeikki Linnakangas2010-07-05
| | | | | | | | | | | being used in a PL/pgSQL FOR loop is closed was inadequate, as Tom Lane pointed out. The bug affects FOR statement variants too, because you can close an implicitly created cursor too by guessing the "<unnamed portal X>" name created for it. To fix that, "pin" the portal to prevent it from being dropped while it's being used in a PL/pgSQL FOR loop. Backpatch all the way to 7.4 which is the oldest supported version.
* Allow REASSIGNED OWNED to handle opclasses and opfamilies.Robert Haas2010-07-03
| | | | | | | | Backpatch to 8.3, which is as far back as we have opfamilies. The opclass portion could probably be backpatched to 8.2, when REASSIGN OWNED was added, but for now I have not done that. Asko Tiidumaa, with minor adjustments by me.
* Move copydir.c from src/port to src/backend/storage/fileRobert Haas2010-07-02
| | | | | | | | | | | | | The previous commit to make copydir() interruptible prevented postgres.exe from linking on MinGW and Cygwin, because on those platforms libpgport_srv.a can't freely reference symbols defined by the backend. Since that code is already backend-specific anyway, just move the whole file into the backend rather than adding further kludges to deal with the symbols needed by CHECK_FOR_INTERRUPTS(). This probably needs some further cleanup, but this commit just moves the file as-is, which should hopefully be enough to turn the buildfarm green again.
* Allow ALTER TABLE .. SET TABLESPACE to be interrupted.Robert Haas2010-07-01
| | | | | | Backpatch to 8.0, where tablespaces were introduced. Guillaume Lelarge
* stringToNode() and deparse_expression_pretty() crash on invalid input,Heikki Linnakangas2010-06-30
| | | | | | | | | | but we have nevertheless exposed them to users via pg_get_expr(). It would be too much maintenance effort to rigorously check the input, so put a hack in place instead to restrict pg_get_expr() so that the argument must come from one of the system catalog columns known to contain valid expressions. Per report from Rushabh Lathia. Backpatch to 7.4 which is the oldest supported version at the moment.
* Fix mishandling of whole-row Vars referencing a view or sub-select.Tom Lane2010-06-21
| | | | | | | | If such a Var appeared within a nested sub-select, we failed to translate it correctly during pullup of the view, because the recursive call to replace_rte_variables_mutator was looking for the wrong sublevels_up value. Bug was introduced during the addition of the PlaceHolderVar mechanism. Per bug #5514 from Marcos Castedo.
* Make the walwriter close it's handle to an old xlog segment if it's no longerMagnus Hagander2010-06-09
| | | | | | | | | the current one. Not doing this would leave the walwriter with a handle to a deleted file if there was nothing for it to do for a long period of time, preventing the file from being completely removed. Reported by Tollef Fog Heen, and thanks to Heikki for some hand-holding with the patch.
* Ensure default-only storage parameters for TOAST relationsItagaki Takahiro2010-06-07
| | | | | | | | | | | | | | | | | | to be initialized with proper values. Affected parameters are fillfactor, analyze_threshold, and analyze_scale_factor. Especially uninitialized fillfactor caused inefficient page usage because we built a StdRdOptions struct in which fillfactor is zero if any reloption is set for the toast table. In addition, we disallow toast.autovacuum_analyze_threshold and toast.autovacuum_analyze_scale_factor because we didn't actually support them; they are always ignored. Report by Rumko on pgsql-bugs on 12 May 2010. Analysis by Tom Lane and Alvaro Herrera. Patch by me. Backpatch to 8.4.
* Fix misuse of Lossy Counting (LC) algorithm in compute_tsvector_stats().Tom Lane2010-05-30
| | | | | | | | | | | | | | | | | | | We must filter out hashtable entries with frequencies less than those specified by the algorithm, else we risk emitting junk entries whose actual frequency is much less than other lexemes that did not get tabulated. This is bad enough by itself, but even worse is that tsquerysel() believes that the minimum frequency seen in pg_statistic is a hard upper bound for lexemes not included, and was thus underestimating the frequency of non-MCEs. Also, set the threshold frequency to something with a little bit of theory behind it, to wit assume that the input distribution is approximately Zipfian. This might need adjustment in future, but some preliminary experiments suggest that it's not too unreasonable. Back-patch to 8.4, where this code was introduced. Jan Urbanski, with some editorialization by Tom
* Rewrite LIKE's %-followed-by-_ optimization so it really works (this timeTom Lane2010-05-28
| | | | | | | | | | | for sure ;-)). It now also optimizes more cases, such as %_%_. Improve comments too. Per bug #5478. In passing, also rename the TCHAR macro to GETCHAR, because pgindent is messing with the formatting of the former (apparently it now thinks TCHAR is a typedef name). Back-patch to 8.3, where the bug was introduced.
* Rejigger mergejoin logic so that a tuple with a null in the first merge columnTom Lane2010-05-28
| | | | | | | | | | | | | | | | | | | is treated like end-of-input, if nulls sort last in that column and we are not doing outer-join filling for that input. In such a case, the tuple cannot join to anything from the other input (because we assume mergejoinable operators are strict), and neither can any tuple following it in the sort order. If we're not interested in doing outer-join filling we can just pretend the tuple and its successors aren't there at all. This can save a great deal of time in situations where there are many nulls in the join column, as in a recent example from Scott Marlowe. Also, since the planner tends to not count nulls in its mergejoin scan selectivity estimates, this is an important fix to make the runtime behavior more like the estimate. I regard this as an omission in the patch I wrote years ago to teach mergejoin that tuples containing nulls aren't joinable, so I'm back-patching it. But only to 8.3 --- in older versions, we didn't have a solid notion of whether nulls sort high or low, so attempting to apply this optimization could break things.
* Change ps_status.c to explicitly track the current logical length of ps_buffer.Tom Lane2010-05-27
| | | | | | | | | | | This saves cycles in get_ps_display() on many popular platforms, and more importantly ensures that get_ps_display() will correctly return an empty string if init_ps_display() hasn't been called yet. Per trouble report from Ray Stell, in which log_line_prefix %i produced junk early in backend startup. Back-patch to 8.0. 7.4 doesn't have %i and its version of get_ps_display() makes no pretense of avoiding pad junk anyhow.
* Make CREATE INDEX run expression preprocessing on a proposed index expressionTom Lane2010-05-27
| | | | | | | | | | | | | | | | | | | | | before it checks whether the expression is immutable. This covers two cases that were previously handled poorly: 1. SQL function inlining could reduce the apparent volatility of the expression, allowing an expression to be accepted where it previously would not have been. As an example, polymorphic functions must be marked with the worst-case volatility they have for any argument type, but for specific argument types they might not be so volatile, so indexing could be allowed. (Since the planner will refuse to inline functions in cases where the apparent volatility of the expression would increase, this won't break any cases that were accepted before.) 2. A nominally immutable function could have default arguments that are volatile expressions. In such a case insertion of the defaults will increase both the apparent and actual volatility of the expression, so it is *necessary* to check this before allowing the expression to be indexed. Back-patch to 8.4, where default arguments were introduced.
* Fix oversight in construction of sort/unique plans for UniquePaths.Tom Lane2010-05-25
| | | | | | | | | | | | | If the original IN operator is cross-type, for example int8 = int4, we need to use int4 < int4 to sort the inner data and int4 = int4 to unique-ify it. We got the first part of that right, but tried to use the original IN operator for the equality checks. Per bug #5472 from Vlad Romascanu. Backpatch to 8.4, where the bug was introduced by the patch that unified SortClause and GroupClause. I was able to take out a whole lot of on-the-fly calls of get_equality_op_for_ordering_op(), but failed to realize that I needed to put one back in right here :-(
* Translation updatePeter Eisentraut2010-05-13
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* Cause the archiver process to adopt new postgresql.conf settings (particularlyTom Lane2010-05-11
| | | | | | | | | | archive_command) as soon as possible, namely just before issuing a new call of archive_command, even when there is a backlog of files to be archived. The original coding would only absorb new settings after clearing the backlog and returning to the outer loop. Per discussion. Back-patch to 8.3. The logic in prior versions is a bit different and it doesn't seem worth taking any risks of breaking it.
* Set per-function GUC settings during validating the function.Itagaki Takahiro2010-05-11
| | | | | | | Now validators work properly even when the settings contain parameters that affect behavior of the function, like search_path. Reported by Erwin Brandstetter.
* Work around a subtle portability problem in use of printf %s format.Tom Lane2010-05-08
| | | | | | | | | | | | | Depending on which spec you read, field widths and precisions in %s may be counted either in bytes or characters. Our code was assuming bytes, which is wrong at least for glibc's implementation, and in any case libc might have a different idea of the prevailing encoding than we do. Hence, for portable results we must avoid using anything more complex than just "%s" unless the string to be printed is known to be all-ASCII. This patch fixes the cases I could find, including the psql formatting failure reported by Hernan Gonzalez. In HEAD only, I also added comments to some places where it appears safe to continue using "%.*s".
* Fix replay of XLOG_HEAP_NEWPAGE WAL records to pay attention to the forknumTom Lane2010-05-02
| | | | | | | | | | | | | | | field of the WAL record. The previous coding always wrote to the main fork, resulting in data corruption if the page was meant to go into a non-default fork. At present, the only operation that can produce such WAL records is ALTER TABLE/INDEX SET TABLESPACE when executed with archive_mode = on. Data corruption would be observed on standby slaves, and could occur on the master as well if a database crash and recovery occurred after committing the ALTER and before the next checkpoint. Per report from Gordon Shannon. Back-patch to 8.4; the problem doesn't exist in earlier branches because we didn't have a concept of multiple relation forks then.
* Add code to InternalIpcMemoryCreate() to handle the case where shmget()Tom Lane2010-05-01
| | | | | | | | | | | | | | | | returns EINVAL for an existing shared memory segment. Although it's not terribly sensible, that behavior does meet the POSIX spec because EINVAL is the appropriate error code when the existing segment is smaller than the requested size, and the spec explicitly disclaims any particular ordering of error checks. Moreover, it does in fact happen on OS X and probably other BSD-derived kernels. (We were able to talk NetBSD into changing their code, but purging that behavior from the wild completely seems unlikely to happen.) We need to distinguish collision with a pre-existing segment from invalid size request in order to behave sensibly, so it's worth some extra code here to get it right. Per report from Gavin Kistner and subsequent investigation. Back-patch to all supported versions, since any of them could get used with a kernel having the debatable behavior.
* On Windows, syslogger runs in two threads. The main thread processes configHeikki Linnakangas2010-04-16
| | | | | | | | reload and rotation signals, and a helper thread reads messages from the pipe and writes them to the log file. However, server code isn't generally thread-safe, so if both try to do e.g palloc()/pfree() at the same time, bad things will happen. To fix that, use a critical section (which is like a mutex) to enforce that only one the threads are active at a time.
* Fix a problem introduced by my patch of 2010-01-12 that revised the wayTom Lane2010-04-14
| | | | | | | | | | | | | | | | | | | | | relcache reload works. In the patched code, a relcache entry in process of being rebuilt doesn't get unhooked from the relcache hash table; which means that if a cache flush occurs due to sinval queue overrun while we're rebuilding it, the entry could get blown away by RelationCacheInvalidate, resulting in crash or misbehavior. Fix by ensuring that an entry being rebuilt has positive refcount, so it won't be seen as a target for removal if a cache flush occurs. (This will mean that the entry gets rebuilt twice in such a scenario, but that's okay.) It appears that the problem can only arise within a transaction that has previously reassigned the relfilenode of a pre-existing table, via TRUNCATE or a similar operation. Per bug #5412 from Rusty Conover. Back-patch to 8.2, same as the patch that introduced the problem. I think that the failure can't actually occur in 8.2, since it lacks the rd_newRelfilenodeSubid optimization, but let's make it work like the later branches anyway. Patch by Heikki, slightly editorialized on by me.
* Don't pass an invalid file handle to dup2(). That causes a crash onHeikki Linnakangas2010-04-01
| | | | | | | | | | | Windows, thanks to a feature in CRT called Parameter Validation. Backpatch to 8.2, which is the oldest version supported on Windows. In 8.2 and 8.3 also backpatch the earlier change to use DEVNULL instead of NULL_DEV #define for a /dev/null-like device. NULL_DEV was hard-coded to "/dev/null" regardless of platform, which didn't work on Windows, while DEVNULL works on all platforms. Restarting syslogger didn't work on Windows on versions 8.3 and below because of that.
* Fix "constraint_exclusion = partition" logic so that it will also attemptTom Lane2010-03-30
| | | | | | constraint exclusion on an inheritance set that is the target of an UPDATE or DELETE query. Per gripe from Marc Cousin. Back-patch to 8.4 where the feature was introduced.
* Prevent ALTER USER f RESET ALL from removing the settings that were put thereAlvaro Herrera2010-03-25
| | | | | | | | by a superuser -- "ALTER USER f RESET setting" already disallows removing such a setting. Apply the same treatment to ALTER DATABASE d RESET ALL when run by a database owner that's not superuser.
* Fix thinko in log message for "sameuser" ident map mismatch: the providedTom Lane2010-03-24
| | | | | | | and authenticated usernames were swapped. Reported by Bryan Henderson in bug #5386. Also clean up poorly-maintained header comment for this function.
* Clear error_context_stack and debug_query_string at the beginning of proc_exit,Tom Lane2010-03-20
| | | | | | | | | | | | | so that we won't try to attach any context printouts to messages that get emitted while exiting. Per report from Dennis Koegel, the context functions won't necessarily work after we've started shutting down the backend, and it seems possible that debug_query_string could be pointing at freed storage as well. The context information doesn't seem particularly relevant to such messages anyway, so there's little lost by suppressing it. Back-patch to all supported branches. I can only demonstrate a crash with log_disconnections messages back to 8.1, but the risk seems real in 8.0 and before anyway.
* Modify error context callback functions to not assume that they can fetchTom Lane2010-03-19
| | | | | | | | | | | | | | | | | | catalog entries via SearchSysCache and related operations. Although, at the time that these callbacks are called by elog.c, we have not officially aborted the current transaction, it still seems rather risky to initiate any new catalog fetches. In all these cases the needed information is readily available in the caller and so it's just a matter of a bit of extra notation to pass it to the callback. Per crash report from Dennis Koegel. I've concluded that the real fix for his problem is to clear the error context stack at entry to proc_exit, but it still seems like a good idea to make the callbacks a bit less fragile for other cases. Backpatch to 8.4. We could go further back, but the patch doesn't apply cleanly. In the absence of proof that this fixes something and isn't just paranoia, I'm not going to expend the effort.
* Fix bug in %r handling in recovery_end_command, it always came out as 0Heikki Linnakangas2010-03-18
| | | | | | | because InRedo was cleared before recovery_end_command was executed. Also, always take ControlFileLock when reading checkpoint location for %r. That didn't matter before, but in 8.4 bgwriter is active during recovery and can modify the control file concurrently.
* Add missing reset of need_initialization in reloptions code.Tom Lane2010-03-11
| | | | | This resulted in useless extra work during every call of parseRelOptions, but no bad effects other than that. Noted by Alvaro.
* Disallow gssapi authentication on local connections, since itMagnus Hagander2010-03-08
| | | | | | requires a hostname to function. Noted by Zdenek Kotala
* Fix warning messages in restrict_and_check_grant() to include the column nameTom Lane2010-03-06
| | | | | | | | | | when warning about column-level privileges. This is more useful than before and makes the apparent duplication complained of by Piyush Newe not so duplicate. Also fix lack of quote marks in a related message text. Back-patch to 8.4, where column-level privileges were introduced. Stephen Frost
* When reading pg_hba.conf and similar files, do not treat @file as an inclusionTom Lane2010-03-06
| | | | | | | | | | | | | | | | | | | | | | | unless (1) the @ isn't quoted and (2) the filename isn't empty. This guards against unexpectedly treating usernames or other strings in "flat files" as inclusion requests, as seen in a recent trouble report from Ed L. The empty-filename case would be guaranteed to misbehave anyway, because our subsequent path-munging behavior results in trying to read the directory containing the current input file. I think this might finally explain the report at http://archives.postgresql.org/pgsql-bugs/2004-05/msg00132.php of a crash after printing "authentication file token too long, skipping", since I was able to duplicate that message (though not a crash) on a platform where stdio doesn't refuse to read directories. We never got far in investigating that problem, but now I'm suspicious that the trigger condition was an @ in the flat password file. Back-patch to all active branches since the problem can be demonstrated in all branches except HEAD. The test case, creating a user named "@", doesn't cause a problem in HEAD since we got rid of the flat password file. Nonetheless it seems like a good idea to not consider quoted @ as a file inclusion spec, so I changed HEAD too.
* Fix IsBinaryCoercible to not confuse a cast using in/out functionsHeikki Linnakangas2010-03-04
| | | | | | with binary compatibility. Backpatch to 8.4 where INOUT casts were introduced.
* Fix a couple of places that would loop forever if attempts to read a stdio fileTom Lane2010-03-03
| | | | | | | set ferror() but never set feof(). This is known to be the case for recent glibc when trying to read a directory as a file, and might be true for other platforms/cases too. Per report from Ed L. (There is more that we ought to do about his report, but this is one easily identifiable issue.)
* Export xml.c's libxml-error-handling support so that contrib/xml2 can use itTom Lane2010-03-03
| | | | | | | | | too, instead of duplicating the functionality (badly). I renamed xml_init to pg_xml_init, because the former seemed just a bit too generic to be safe as a global symbol. I considered likewise renaming xml_ereport to pg_xml_ereport, but felt that the reference to ereport probably made it sufficiently PG-centric already.
* Allow predicate_refuted_by() to deduce that NOT A refutes A.Tom Lane2010-02-25
| | | | | | | | | | | | | | | | | | | | | We had originally made the stronger assumption that NOT A refutes any B if B implies A, but this fails in three-valued logic, because we need to prove B is false not just that it's not true. However the logic does go through if B is equal to A. Recognizing this limited case is enough to handle examples that arise when we have simplified "bool_var = true" or "bool_var = false" to just "bool_var" or "NOT bool_var". If we had not done that simplification then the btree-operator proof logic would have been able to prove that the expressions were contradictory, but only for identical expressions being compared to the constants; so handling identical A and B covers all the same cases. The motivation for doing this is to avoid unexpected asymmetrical behavior when a partitioned table uses a boolean partitioning column, as in today's gripe from Dominik Sander. Back-patch to 8.2, which is as far back as predicate_refuted_by attempts to do anything at all with NOTs.
* Add configuration parameter ssl_renegotiation_limit to controlMagnus Hagander2010-02-25
| | | | | | | | how often we do SSL session key renegotiation. Can be set to 0 to disable renegotiation completely, which is required if a broken SSL library is used (broken patches to CVE-2009-3555 a known cause) or when using a client library that can't do renegotiation.
* Fix STOP WAL LOCATION in backup history files no to return the nextItagaki Takahiro2010-02-19
| | | | | | | | | | | segment of XLOG_BACKUP_END record even if the the record is placed at a segment boundary. Furthermore the previous implementation could return nonexistent segment file name when the boundary is in segments that has "FE" suffix; We never use segments with "FF" suffix. Backpatch to 8.0, where hot backup was introduced. Reported by Fujii Masao.
* Provide some rather hokey ways for EXPLAIN to print FieldStore and assignmentTom Lane2010-02-18
| | | | | | | | | | | | | | | | | | ArrayRef expressions that are not in the immediate context of an INSERT or UPDATE targetlist. Such cases never arise in stored rules, so ruleutils.c hadn't tried to handle them. However, they do occur in the targetlists of plans derived from such statements, and now that EXPLAIN VERBOSE tries to print targetlists, we need some way to deal with the case. I chose to represent an assignment ArrayRef as "array[subscripts] := source", which is fairly reasonable and doesn't omit any information. However, FieldStore is problematic because the planner will fold multiple assignments to fields of the same composite column into one FieldStore, resulting in a structure that is hard to understand at all, let alone display comprehensibly. So in that case I punted and just made it print the source expression(s). Backpatch to 8.4 --- the lack of functionality exists in older releases, but doesn't seem to be important for lack of anything that would call it.
* Fix ExecEvalArrayRef to pass down the old value of the array element or sliceTom Lane2010-02-18
| | | | | | | | | | | | | being assigned to, in case the expression to be assigned is a FieldStore that would need to modify that value. The need for this was foreseen some time ago, but not implemented then because we did not have arrays of composites. Now we do, but the point evidently got overlooked in that patch. Net result is that updating a field of an array element doesn't work right, as illustrated if you try the new regression test on an unpatched backend. Noted while experimenting with EXPLAIN VERBOSE, which has also got some issues in this area. Backpatch to 8.3, where arrays of composites were introduced.
* Force READY portals into FAILED state when a transaction or subtransactionTom Lane2010-02-18
| | | | | | | | | | | is aborted, if they were created within the failed xact. This prevents ExecutorEnd from being run on them, which is a good idea because they may contain references to tables or other objects that no longer exist. In particular this is hazardous when auto_explain is active, but it's really rather surprising that nobody has seen an issue with this before. I'm back-patching this to 8.4, since that's the first version that contains auto_explain or an ExecutorEnd hook, but I wonder whether we shouldn't back-patch further.