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* Postpone aggregate checks until after collation is assigned.Andrew Gierth2019-01-17
| | | | | | | | | | | | | | | | | | | | | | | Previously, parseCheckAggregates was run before assign_query_collations, but this causes problems if any expression has already had a collation assigned by some transform function (e.g. transformCaseExpr) before parseCheckAggregates runs. The differing collations would cause expressions not to be recognized as equal to the ones in the GROUP BY clause, leading to spurious errors about unaggregated column references. The result was that CASE expr WHEN val ... would fail when "expr" contained a GROUPING() expression or matched one of the group by expressions, and where collatable types were involved; whereas the supposedly identical CASE WHEN expr = val ... would succeed. Backpatch all the way; this appears to have been wrong ever since collations were introduced. Per report from Guillaume Lelarge, analysis and patch by me. Discussion: https://postgr.es/m/CAECtzeVSO_US8C2Khgfv54ZMUOBR4sWq+6_bLrETnWExHT=rFg@mail.gmail.com Discussion: https://postgr.es/m/87muo0k0c7.fsf@news-spur.riddles.org.uk
* Improve ANALYZE's handling of concurrent-update scenarios.Tom Lane2019-01-03
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch changes the rule for whether or not a tuple seen by ANALYZE should be included in its sample. When we last touched this logic, in commit 51e1445f1, we weren't thinking very hard about tuples being UPDATEd by a long-running concurrent transaction. In such a case, we might see the pre-image as either LIVE or DELETE_IN_PROGRESS depending on timing; and we might see the post-image not at all, or as INSERT_IN_PROGRESS. Since the existing code will not sample either DELETE_IN_PROGRESS or INSERT_IN_PROGRESS tuples, this leads to concurrently-updated rows being omitted from the sample entirely. That's not very helpful, and it's especially the wrong thing if the concurrent transaction ends up rolling back. The right thing seems to be to sample DELETE_IN_PROGRESS rows just as if they were live. This makes the "sample it" and "count it" decisions the same, which seems good for consistency. It's clearly the right thing if the concurrent transaction ends up rolling back; in effect, we are sampling as though IN_PROGRESS transactions haven't happened yet. Also, this combination of choices ensures maximum robustness against the different combinations of whether and in which state we might see the pre- and post-images of an update. It's slightly annoying that we end up recording immediately-out-of-date stats in the case where the transaction does commit, but on the other hand the stats are fine for columns that didn't change in the update. And the alternative of sampling INSERT_IN_PROGRESS rows instead seems like a bad idea, because then the sampling would be inconsistent with the way rows are counted for the stats report. Per report from Mark Chambers; thanks to Jeff Janes for diagnosing what was happening. Back-patch to all supported versions. Discussion: https://postgr.es/m/CAFh58O_Myr6G3tcH3gcGrF-=OExB08PJdWZcSBcEcovaiPsrHA@mail.gmail.com
* Don't believe MinMaxExpr is leakproof without checking.Tom Lane2019-01-02
| | | | | | | | | | | | | | | | MinMaxExpr invokes the btree comparison function for its input datatype, so it's only leakproof if that function is. Many such functions are indeed leakproof, but others are not, and we should not just assume that they are. Hence, adjust contain_leaked_vars to verify the leakproofness of the referenced function explicitly. I didn't add a regression test because it would need to depend on some particular comparison function being leaky, and that's a moving target, per discussion. This has been wrong all along, so back-patch to supported branches. Discussion: https://postgr.es/m/31042.1546194242@sss.pgh.pa.us
* Have DISCARD ALL/TEMP remove leftover temp tablesAlvaro Herrera2018-12-27
| | | | | | | | | | | | | | | | | | | | Previously, it would only remove temp tables created in the same session; but if the session uses the BackendId of a previously crashed backend that left temp tables around, those would not get removed. Since autovacuum would not drop them either (because it sees that the BackendId is in use by the current session) these can cause annoying xid-wraparound warnings. Apply to branches 9.4 to 10. This is not a problem since version 11, because commit 943576bddcb5 added state tracking that makes autovacuum realize that those temp tables are not ours, so it removes them. This is useful to handle in DISCARD, because even though it does not handle all situations, it does handle the common one where a connection pooler keeps the same session open for an indefinitely long time. Discussion: https://postgr.es/m/20181226190834.wsk2wzott5yzrjiq@alvherre.pgsql Reviewed-by: Takayuki Tsunakawa, Michaël Paquier
* Make autovacuum more selective about temp tables to keepAlvaro Herrera2018-12-27
| | | | | | | | | | | | | | | | | | | When temp tables are in danger of XID wraparound, autovacuum drops them; however, it preserves those that are owned by a working session. This is desirable, except when the session is connected to a different database (because the temp tables cannot be from that session), so make it only keep the temp tables only if the backend is in the same database as the temp tables. This is not bulletproof: it fails to detect temp tables left by a session whose backend ID is reused in the same database but the new session does not use temp tables. Commit 943576bddcb5 fixes that case too, for branches 11 and up (which is why we don't apply this fix to those branches), but back-patching that one is not universally agreed on. Discussion: https://postgr.es/m/20181214162843.37g6h3txto43akrb@alvherre.pgsql Reviewed-by: Takayuki Tsunakawa, Michaël Paquier
* Ignore inherited temp relations from other sessions when truncatingMichael Paquier2018-12-27
| | | | | | | | | | | | | | | | | | Inheritance trees can include temporary tables if the parent is permanent, which makes possible the presence of multiple temporary children from different sessions. Trying to issue a TRUNCATE on the parent in this scenario causes a failure, so similarly to any other queries just ignore such cases, which makes TRUNCATE work transparently. This makes truncation behave similarly to any other DML query working on the parent table with queries which need to be issues on children. A set of isolation tests is added to cover basic cases. Reported-by: Zhou Digoal Author: Amit Langote, Michael Paquier Discussion: https://postgr.es/m/15565-ce67a48d0244436a@postgresql.org Backpatch-through: 9.4
* Prioritize history files when archivingMichael Paquier2018-12-24
| | | | | | | | | | | | | | | | | | | | | | | | At the end of recovery for the post-promotion process, a new history file is created followed by the last partial segment of the previous timeline. Based on the timing, the archiver would first try to archive the last partial segment and then the history file. This can delay the detection of a new timeline taken, particularly depending on the time it takes to transfer the last partial segment as it delays the moment the history file of the new timeline gets archived. This can cause promoted standbys to use the same timeline as one already taken depending on the circumstances if multiple instances look at archives at the same location. This commit changes the order of archiving so as history files are archived in priority over other file types, which reduces the likelihood of the same timeline being taken (still not reducing the window to zero), and it makes the archiver behave more consistently with the startup process doing its post-promotion business. Author: David Steele Reviewed-by: Michael Paquier, Kyotaro Horiguchi Discussion: https://postgr.es/m/929068cf-69e1-bba2-9dc0-e05986aed471@pgmasters.net Backpatch-through: 9.5
* Fix ancient thinko in mergejoin cost estimation.Tom Lane2018-12-18
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | "rescanratio" was computed as 1 + rescanned-tuples / total-inner-tuples, which is sensible if it's to be multiplied by total-inner-tuples or a cost value corresponding to scanning all the inner tuples. But in reality it was (mostly) multiplied by inner_rows or a related cost, numbers that take into account the possibility of stopping short of scanning the whole inner relation thanks to a limited key range in the outer relation. This'd still make sense if we could expect that stopping short would result in a proportional decrease in the number of tuples that have to be rescanned. It does not, however. The argument that establishes the validity of our estimate for that number is independent of whether we scan all of the inner relation or stop short, and experimentation also shows that stopping short doesn't reduce the number of rescanned tuples. So the correct calculation is 1 + rescanned-tuples / inner_rows, and we should be sure to multiply that by inner_rows or a corresponding cost value. Most of the time this doesn't make much difference, but if we have both a high rescan rate (due to lots of duplicate values) and an outer key range much smaller than the inner key range, then the error can be significant, leading to a large underestimate of the cost associated with rescanning. Per report from Vijaykumar Jain. This thinko appears to go all the way back to the introduction of the rescan estimation logic in commit 70fba7043, so back-patch to all supported branches. Discussion: https://postgr.es/m/CAE7uO5hMb_TZYJcZmLAgO6iD68AkEK6qCe7i=vZUkCpoKns+EQ@mail.gmail.com
* Fix use-after-free bug when renaming constraintsMichael Paquier2018-12-17
| | | | | | | | | This is an oversight from recent commit b13fd344. While on it, tweak the previous test with a better name for the renamed primary key. Detected by buildfarm member prion which forces relation cache release with -DRELCACHE_FORCE_RELEASE. Back-patch down to 9.4 as the previous commit.
* Make constraint rename issue relcache invalidation on target relationMichael Paquier2018-12-17
| | | | | | | | | | | | | | | When a constraint gets renamed, it may have associated with it a target relation (for example domain constraints don't have one). Not invalidating the target relation cache when issuing the renaming can result in issues with subsequent commands that refer to the old constraint name using the relation cache, causing various failures. One pattern spotted was using CREATE TABLE LIKE after a constraint renaming. Reported-by: Stuart <sfbarbee@gmail.com> Author: Amit Langote Reviewed-by: Michael Paquier Discussion: https://postgr.es/m/2047094.V130LYfLq4@station53.ousa.org
* Prevent GIN deleted pages from being reclaimed too earlyAlexander Korotkov2018-12-13
| | | | | | | | | | | | | | | | | | When GIN vacuum deletes a posting tree page, it assumes that no concurrent searchers can access it, thanks to ginStepRight() locking two pages at once. However, since 9.4 searches can skip parts of posting trees descending from the root. That leads to the risk that page is deleted and reclaimed before concurrent search can access it. This commit prevents the risk of above by waiting for every transaction, which might wait to reference this page, to finish. Due to binary compatibility we can't change GinPageOpaqueData to store corresponding transaction id. Instead we reuse page header pd_prune_xid field, which is unused in index pages. Discussion: https://postgr.es/m/31a702a.14dd.166c1366ac1.Coremail.chjischj%40163.com Author: Andrey Borodin, Alexander Korotkov Reviewed-by: Alexander Korotkov Backpatch-through: 9.4
* Prevent deadlock in ginRedoDeletePage()Alexander Korotkov2018-12-13
| | | | | | | | | | | | | | | | | | | | On standby ginRedoDeletePage() can work concurrently with read-only queries. Those queries can traverse posting tree in two ways. 1) Using rightlinks by ginStepRight(), which locks the next page before unlocking its left sibling. 2) Using downlinks by ginFindLeafPage(), which locks at most one page at time. Original lock order was: page, parent, left sibling. That lock order can deadlock with ginStepRight(). In order to prevent deadlock this commit changes lock order to: left sibling, page, parent. Note, that position of parent in locking order seems insignificant, because we only lock one page at time while traversing downlinks. Reported-by: Chen Huajun Diagnosed-by: Chen Huajun, Peter Geoghegan, Andrey Borodin Discussion: https://postgr.es/m/31a702a.14dd.166c1366ac1.Coremail.chjischj%40163.com Author: Alexander Korotkov Backpatch-through: 9.4
* Repair bogus handling of multi-assignment Params in upper plan levels.Tom Lane2018-12-12
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Our support for multiple-set-clauses in UPDATE assumes that the Params referencing a MULTIEXPR_SUBLINK SubPlan will appear before that SubPlan in the targetlist of the plan node that calculates the updated row. (Yeah, it's a hack...) In some PG branches it's possible that a Result node gets inserted between the primary calculation of the update tlist and the ModifyTable node. setrefs.c did the wrong thing in this case and left the upper-level Params as Params, causing a crash at runtime. What it should do is replace them with "outer" Vars referencing the child plan node's output. That's a result of careless ordering of operations in fix_upper_expr_mutator, so we can fix it just by reordering the code. Fix fix_join_expr_mutator similarly for consistency, even though join nodes could never appear in such a context. (In general, it seems likely to be a bit cheaper to use Vars than Params in such situations anyway, so this patch might offer a tiny performance improvement.) The hazard extends back to 9.5 where the MULTIEXPR_SUBLINK stuff was introduced, so back-patch that far. However, this may be a live bug only in 9.6.x and 10.x, as the other branches don't seem to want to calculate the final tlist below the Result node. (That plan shape change between branches might be a mini-bug in itself, but I'm not really interested in digging into the reasons for that right now. Still, add a regression test memorializing what we expect there, so we'll notice if it changes again.) Per bug report from Eduards Bezverhijs. Discussion: https://postgr.es/m/b6cd572a-3e44-8785-75e9-c512a5a17a73@tieto.com
* Add stack depth checks to key recursive functions in backend/nodes/*.c.Tom Lane2018-12-10
| | | | | | | | | | Although copyfuncs.c has a check_stack_depth call in its recursion, equalfuncs.c, outfuncs.c, and readfuncs.c lacked one. This seems unwise. Likewise fix planstate_tree_walker(), in branches where that exists. Discussion: https://postgr.es/m/30253.1544286631@sss.pgh.pa.us
* Fix misapplication of pgstat_count_truncate to wrong relation.Tom Lane2018-12-07
| | | | | | | | | | | | | | | | | | | | | | | | The stanza of ExecuteTruncate[Guts] that truncates a target table's toast relation re-used the loop local variable "rel" to reference the toast rel. This was safe enough when written, but commit d42358efb added code below that that supposed "rel" still pointed to the parent table. Therefore, the stats counter update was applied to the wrong relcache entry (the toast rel not the user rel); and if we were unlucky and that relcache entry had been flushed during reindex_relation, very bad things could ensue. (I'm surprised that CLOBBER_CACHE_ALWAYS testing hasn't found this. I'm even more surprised that the problem wasn't detected during the development of d42358efb; it must not have been tested in any case with a toast table, as the incorrect stats counts are very obvious.) To fix, replace use of "rel" in that code branch with a more local variable. Adjust test cases added by d42358efb so that some of them use tables with toast tables. Per bug #15540 from Pan Bian. Back-patch to 9.5 where d42358efb came in. Discussion: https://postgr.es/m/15540-01078812338195c0@postgresql.org
* Fix handling of synchronous replication for stopping WAL sendersMichael Paquier2018-11-29
| | | | | | | | | | | | | | | | | | | This fixes an oversight from c6c3334 which forgot that if a subset of WAL senders are stopping and in a sync state, other WAL senders could still be waiting for a WAL position to be synced while committing a transaction. However the subset of stopping senders would not release waiters, potentially breaking synchronous replication guarantees. This commit makes sure that even WAL senders stopping are able to release waiters and are tracked properly. On 9.4, this can also trigger an assertion failure when setting for example max_wal_senders to 1 where a WAL sender is not able to find itself as in synchronous state when the instance stops. Reported-by: Paul Guo Author: Paul Guo, Michael Paquier Discussion: https://postgr.es/m/CAEET0ZEv8VFqT3C-cQm6byOB4r4VYWcef1J21dOX-gcVhCSpmA@mail.gmail.com Backpatch-through: 9.4
* Do not decode TOAST data for table rewritesTomas Vondra2018-11-28
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | During table rewrites (VACUUM FULL and CLUSTER), the main heap is logged using XLOG / FPI records, and thus (correctly) ignored in decoding. But the associated TOAST table is WAL-logged as plain INSERT records, and so was logically decoded and passed to reorder buffer. That has severe consequences with TOAST tables of non-trivial size. Firstly, reorder buffer has to keep all those changes, possibly spilling them to a file, incurring I/O costs and disk space. Secondly, ReoderBufferCommit() was stashing all those TOAST chunks into a hash table, which got discarded only after processing the row from the main heap. But as the main heap is not decoded for rewrites, this never happened, so all the TOAST data accumulated in memory, resulting either in excessive memory consumption or OOM. The fix is simple, as commit e9edc1ba already introduced infrastructure (namely HEAP_INSERT_NO_LOGICAL flag) to skip logical decoding of TOAST tables, but it only applied it to system tables. So simply use it for all TOAST data in raw_heap_insert(). That would however solve only the memory consumption issue - the TOAST changes would still be decoded and added to the reorder buffer, and spilled to disk (although without TOAST tuple data, so much smaller). But we can solve that by tweaking DecodeInsert() to just ignore such INSERT records altogether, using XLH_INSERT_CONTAINS_NEW_TUPLE flag, instead of skipping them later in ReorderBufferCommit(). Review: Masahiko Sawada Discussion: https://www.postgresql.org/message-id/flat/1a17c643-e9af-3dba-486b-fbe31bc1823a%402ndquadrant.com Backpatch: 9.4-, where logical decoding was introduced
* Fix float-to-integer coercions to handle edge cases correctly.Tom Lane2018-11-24
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | ftoi4 and its sibling coercion functions did their overflow checks in a way that looked superficially plausible, but actually depended on an assumption that the MIN and MAX comparison constants can be represented exactly in the float4 or float8 domain. That fails in ftoi4, ftoi8, and dtoi8, resulting in a possibility that values near the MAX limit will be wrongly converted (to negative values) when they need to be rejected. Also, because we compared before rounding off the fractional part, the other three functions threw errors for values that really ought to get rounded to the min or max integer value. Fix by doing rint() first (requiring an assumption that it handles NaN and Inf correctly; but dtoi8 and ftoi8 were assuming that already), and by comparing to values that should coerce to float exactly, namely INTxx_MIN and -INTxx_MIN. Also remove some random cosmetic discrepancies between these six functions. This back-patches commits cbdb8b4c0 and 452b637d4. In the 9.4 branch, also back-patch the portion of 62e2a8dc2 that added PG_INTnn_MIN and related constants to c.h, so that these functions can rely on them. Per bug #15519 from Victor Petrovykh. Patch by me; thanks to Andrew Gierth for analysis and discussion. Discussion: https://postgr.es/m/15519-4fc785b483201ff1@postgresql.org
* PANIC on fsync() failure.Thomas Munro2018-11-19
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | On some operating systems, it doesn't make sense to retry fsync(), because dirty data cached by the kernel may have been dropped on write-back failure. In that case the only remaining copy of the data is in the WAL. A subsequent fsync() could appear to succeed, but not have flushed the data. That means that a future checkpoint could apparently complete successfully but have lost data. Therefore, violently prevent any future checkpoint attempts by panicking on the first fsync() failure. Note that we already did the same for WAL data; this change extends that behavior to non-temporary data files. Provide a GUC data_sync_retry to control this new behavior, for users of operating systems that don't eject dirty data, and possibly forensic/testing uses. If it is set to on and the write-back error was transient, a later checkpoint might genuinely succeed (on a system that does not throw away buffers on failure); if the error is permanent, later checkpoints will continue to fail. The GUC defaults to off, meaning that we panic. Back-patch to all supported releases. There is still a narrow window for error-loss on some operating systems: if the file is closed and later reopened and a write-back error occurs in the intervening time, but the inode has the bad luck to be evicted due to memory pressure before we reopen, we could miss the error. A later patch will address that with a scheme for keeping files with dirty data open at all times, but we judge that to be too complicated to back-patch. Author: Craig Ringer, with some adjustments by Thomas Munro Reported-by: Craig Ringer Reviewed-by: Robert Haas, Thomas Munro, Andres Freund Discussion: https://postgr.es/m/20180427222842.in2e4mibx45zdth5%40alap3.anarazel.de
* Don't forget about failed fsync() requests.Thomas Munro2018-11-19
| | | | | | | | | | | | If fsync() fails, md.c must keep the request in its bitmap, so that future attempts will try again. Back-patch to all supported releases. Author: Thomas Munro Reviewed-by: Amit Kapila Reported-by: Andrew Gierth Discussion: https://postgr.es/m/87y3i1ia4w.fsf%40news-spur.riddles.org.uk
* Initialize TransactionState and user ID consistently at transaction startMichael Paquier2018-11-14
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | If a failure happens when a transaction is starting between the moment the transaction status is changed from TRANS_DEFAULT to TRANS_START and the moment the current user ID and security context flags are fetched via GetUserIdAndSecContext(), or before initializing its basic fields, then those may get reset to incorrect values when the transaction aborts, leaving the session in an inconsistent state. One problem reported is that failing a starting transaction at the first query of a session could cause several kinds of system crashes on the follow-up queries. In order to solve that, move the initialization of the transaction state fields and the call of GetUserIdAndSecContext() in charge of fetching the current user ID close to the point where the transaction status is switched to TRANS_START, where there cannot be any error triggered in-between, per an idea of Tom Lane. This properly ensures that the current user ID, the security context flags and that the basic fields of TransactionState remain consistent even if the transaction fails while starting. Reported-by: Richard Guo Diagnosed-By: Richard Guo Author: Michael Paquier Reviewed-by: Tom Lane Discussion: https://postgr.es/m/CAN_9JTxECSb=pEPcb0a8d+6J+bDcOZ4=DgRo_B7Y5gRHJUM=Rw@mail.gmail.com Backpatch-through: 9.4
* Limit the number of index clauses considered in choose_bitmap_and().Tom Lane2018-11-12
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | classify_index_clause_usage() is O(N^2) in the number of distinct index qual clauses it considers, because of its use of a simple search list to store them. For nearly all queries, that's fine because only a few clauses will be considered. But Alexander Kuzmenkov reported a machine-generated query with 80000 (!) index qual clauses, which caused this code to take forever. Somewhat remarkably, this is the only O(N^2) behavior we now have for such a query, so let's fix it. We can get rid of the O(N^2) runtime for cases like this without much damage to the functionality of choose_bitmap_and() by separating out paths with "too many" qual or pred clauses, and deeming them to always be nonredundant with other paths. Then their clauses needn't go into the search list, so it doesn't get too long, but we don't lose the ability to consider bitmap AND plans altogether. I set the threshold for "too many" to be 100 clauses per path, which should be plenty to ensure no change in planning behavior for normal queries. There are other things we could do to make this go faster, but it's not clear that it's worth any additional effort. 80000 qual clauses require a whole lot of work in many other places, too. The code's been like this for a long time, so back-patch to all supported branches. The troublesome query only works back to 9.5 (in 9.4 it fails with stack overflow in the parser); so I'm not sure that fixing this in 9.4 has any real-world benefit, but perhaps it does. Discussion: https://postgr.es/m/90c5bdfa-d633-dabe-9889-3cf3e1acd443@postgrespro.ru
* Fix missing role dependencies for some schema and type ACLs.Tom Lane2018-11-09
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch fixes several related cases in which pg_shdepend entries were never made, or were lost, for references to roles appearing in the ACLs of schemas and/or types. While that did no immediate harm, if a referenced role were later dropped, the drop would be allowed and would leave a dangling reference in the object's ACL. That still wasn't a big problem for normal database usage, but it would cause obscure failures in subsequent dump/reload or pg_upgrade attempts, taking the form of attempts to grant privileges to all-numeric role names. (I think I've seen field reports matching that symptom, but can't find any right now.) Several cases are fixed here: 1. ALTER DOMAIN SET/DROP DEFAULT would lose the dependencies for any existing ACL entries for the domain. This case is ancient, dating back as far as we've had pg_shdepend tracking at all. 2. If a default type privilege applies, CREATE TYPE recorded the ACL properly but forgot to install dependency entries for it. This dates to the addition of default privileges for types in 9.2. 3. If a default schema privilege applies, CREATE SCHEMA recorded the ACL properly but forgot to install dependency entries for it. This dates to the addition of default privileges for schemas in v10 (commit ab89e465c). Another somewhat-related problem is that when creating a relation rowtype or implicit array type, TypeCreate would apply any available default type privileges to that type, which we don't really want since such an object isn't supposed to have privileges of its own. (You can't, for example, drop such privileges once they've been added to an array type.) ab89e465c is also to blame for a race condition in the regression tests: privileges.sql transiently installed globally-applicable default privileges on schemas, which sometimes got absorbed into the ACLs of schemas created by concurrent test scripts. This should have resulted in failures when privileges.sql tried to drop the role holding such privileges; but thanks to the bug fixed here, it instead led to dangling ACLs in the final state of the regression database. We'd managed not to notice that, but it became obvious in the wake of commit da906766c, which allowed the race condition to occur in pg_upgrade tests. To fix, add a function recordDependencyOnNewAcl to encapsulate what callers of get_user_default_acl need to do; while the original call sites got that right via ad-hoc code, none of the later-added ones have. Also change GenerateTypeDependencies to generate these dependencies, which requires adding the typacl to its parameter list. (That might be annoying if there are any extensions calling that function directly; but if there are, they're most likely buggy in the same way as the core callers were, so they need work anyway.) While I was at it, I changed GenerateTypeDependencies to accept most of its parameters in the form of a Form_pg_type pointer, making its parameter list a bit less unwieldy and mistake-prone. The test race condition is fixed just by wrapping the addition and removal of default privileges into a single transaction, so that that state is never visible externally. We might eventually prefer to separate out tests of default privileges into a script that runs by itself, but that would be a bigger change and would make the tests run slower overall. Back-patch relevant parts to all supported branches. Discussion: https://postgr.es/m/15719.1541725287@sss.pgh.pa.us
* Disallow setting client_min_messages higher than ERROR.Tom Lane2018-11-08
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Previously it was possible to set client_min_messages to FATAL or PANIC, which had the effect of suppressing transmission of regular ERROR messages to the client. Perhaps that seemed like a useful option in the past, but the trouble with it is that it breaks guarantees that are explicitly made in our FE/BE protocol spec about how a query cycle can end. While libpq and psql manage to cope with the omission, that's mostly because they are not very bright; client libraries that have more semantic knowledge are likely to get confused. Notably, pgODBC doesn't behave very sanely. Let's fix this by getting rid of the ability to set client_min_messages above ERROR. In HEAD, just remove the FATAL and PANIC options from the set of allowed enum values for client_min_messages. (This change also affects trace_recovery_messages, but that's OK since these aren't useful values for that variable either.) In the back branches, there was concern that rejecting these values might break applications that are explicitly setting things that way. I'm pretty skeptical of that argument, but accommodate it by accepting these values and then internally setting the variable to ERROR anyway. In all branches, this allows a couple of tiny simplifications in the logic in elog.c, so do that. Also respond to the point that was made that client_min_messages has exactly nothing to do with the server's logging behavior, and therefore does not belong in the "When To Log" subsection of the documentation. The "Statement Behavior" subsection is a better match, so move it there. Jonah Harris and Tom Lane Discussion: https://postgr.es/m/7809.1541521180@sss.pgh.pa.us Discussion: https://postgr.es/m/15479-ef0f4cc2fd995ca2@postgresql.org
* GUC: adjust effective_cache_size SQL descriptionsBruce Momjian2018-11-06
| | | | | | | | | | Follow on patch for commit 3e0f1a4741f564c1a2fa6e944729d6967355d8c7. Reported-by: Peter Eisentraut Discussion: https://postgr.es/m/369ec766-b947-51bd-4dad-6fb9e026439f@2ndquadrant.com Backpatch-through: 9.4
* Fix copy-paste error in errhint() introduced in 691d79a07933.Andres Freund2018-11-05
| | | | | | Reported-By: Petr Jelinek Discussion: https://postgr.es/m/c95a620b-34f0-7930-aeb5-f7ab804f26cb@2ndquadrant.com Backpatch: 9.4-, like the previous commit
* Translation updatesPeter Eisentraut2018-11-05
| | | | | Source-Git-URL: https://git.postgresql.org/git/pgtranslation/messages.git Source-Git-Hash: fa2a38c6d1759866a6840952dd2fbd71b9a69955
* Make ts_locale.c's character-type functions cope with UTF-16.Tom Lane2018-11-03
| | | | | | | | | | | | | | | | | | | | | | On Windows, in UTF8 database encoding, what char2wchar() produces is UTF16 not UTF32, ie, characters above U+FFFF will be represented by surrogate pairs. t_isdigit() and siblings did not account for this and failed to provide a large enough result buffer. That in turn led to bogus "invalid multibyte character for locale" errors, because contrary to what you might think from char2wchar()'s documentation, its Windows code path doesn't cope sanely with buffer overflow. The solution for t_isdigit() and siblings is pretty clear: provide a 3-wchar_t result buffer not 2. char2wchar() also needs some work to provide more consistent, and more accurately documented, buffer overrun behavior. But that's a bigger job and it doesn't actually have any immediate payoff, so leave it for later. Per bug #15476 from Kenji Uno, who deserves credit for identifying the cause of the problem. Back-patch to all active branches. Discussion: https://postgr.es/m/15476-4314f480acf0f114@postgresql.org
* GUC: adjust effective_cache_size docs and SQL descriptionBruce Momjian2018-11-02
| | | | | | | | | | | Clarify that effective_cache_size is both kernel buffers and shared buffers. Reported-by: nat@makarevitch.org Discussion: https://postgr.es/m/153685164808.22334.15432535018443165207@wrigleys.postgresql.org Backpatch-through: 9.3
* Fix error message typo introduced 691d79a07933.Andres Freund2018-11-01
| | | | | | Reported-By: Michael Paquier Discussion: https://postgr.es/m/20181101003405.GB1727@paquier.xyz Backpatch: 9.4-, like the previous commit
* Disallow starting server with insufficient wal_level for existing slot.Andres Freund2018-10-31
| | | | | | | | | | | | | | | | Previously it was possible to create a slot, change wal_level, and restart, even if the new wal_level was insufficient for the slot. That's a problem for both logical and physical slots, because the necessary WAL records are not generated. This removes a few tests in newer versions that, somewhat inexplicably, whether restarting with a too low wal_level worked (a buggy behaviour!). Reported-By: Joshua D. Drake Author: Andres Freund Discussion: https://postgr.es/m/20181029191304.lbsmhshkyymhw22w@alap3.anarazel.de Backpatch: 9.4-, where replication slots where introduced
* Fix memory leak in repeated SPGIST index scans.Tom Lane2018-10-31
| | | | | | | | | | | | | | | | | | | | | | | spgendscan neglected to pfree all the memory allocated by spgbeginscan. It's possible to get away with that in most normal queries, since the memory is allocated in the executor's per-query context which is about to get deleted anyway; but it causes severe memory leakage during creation or filling of large exclusion-constraint indexes. Also, document that amendscan is supposed to free what ambeginscan allocates. The docs' lack of clarity on that point probably caused this bug to begin with. (There is discussion of changing that API spec going forward, but I don't think it'd be appropriate for the back branches.) Per report from Bruno Wolff. It's been like this since the beginning, so back-patch to all active branches. In HEAD, also fix an independent leak caused by commit 2a6368343 (allocating memory during spgrescan instead of spgbeginscan, which might be all right if it got cleaned up, but it didn't). And do a bit of code beautification on that commit, too. Discussion: https://postgr.es/m/20181024012314.GA27428@wolff.to
* Server-side fix for delayed NOTIFY and SIGTERM processing.Tom Lane2018-10-19
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Commit 4f85fde8e introduced some code that was meant to ensure that we'd process cancel, die, sinval catchup, and notify interrupts while waiting for client input. But there was a flaw: it supposed that the process latch would be set upon arrival at secure_read() if any such interrupt was pending. In reality, we might well have cleared the process latch at some earlier point while those flags remained set -- particularly notifyInterruptPending, which can't be handled as long as we're within a transaction. To fix the NOTIFY case, also attempt to process signals (except ProcDiePending) before trying to read. Also, if we see that ProcDiePending is set before we read, forcibly set the process latch to ensure that we will handle that signal promptly if no data is available. I also made it set the process latch on the way out, in case there is similar logic elsewhere. (It remains true that we won't service ProcDiePending here unless we need to wait for input.) The code for handling ProcDiePending during a write needs those changes, too. Also be a little more careful about when to reset whereToSendOutput, and improve related comments. Back-patch to 9.5 where this code was added. I'm not entirely convinced that older branches don't have similar issues, but the complaint at hand is just about the >= 9.5 code. Jeff Janes and Tom Lane Discussion: https://postgr.es/m/CAOYf6ec-TmRYjKBXLLaGaB-jrd=mjG1Hzn1a1wufUAR39PQYhw@mail.gmail.com
* Avoid statically allocating gmtsub()'s timezone workspace.Tom Lane2018-10-16
| | | | | | | | | | | | | | | | | | | | | | | localtime.c's "struct state" is a rather large object, ~23KB. We were statically allocating one for gmtsub() to use to represent the GMT timezone, even though that function is not at all heavily used and is never reached in most backends. Let's malloc it on-demand, instead. This does pose the question of how to handle a malloc failure, but there's already a well-defined error report convention here, ie set errno and return NULL. We have but one caller of pg_gmtime in HEAD, and two in back branches, neither of which were troubling to check for error. Make them do so. The possible errors are sufficiently unlikely (out-of-range timestamp, and now malloc failure) that I think elog() is adequate. Back-patch to all supported branches to keep our copies of the IANA timezone code in sync. This particular change is in a stanza that already differs from upstream, so it's a wash for maintenance purposes --- but only as long as we keep the branches the same. Discussion: https://postgr.es/m/20181015200754.7y7zfuzsoux2c4ya@alap3.anarazel.de
* Check for stack overrun in standard_ProcessUtility().Tom Lane2018-10-15
| | | | | | | | | | | ProcessUtility can recurse, and indeed can be driven to infinite recursion, so it ought to have a check_stack_depth() call. This covers the reported bug (portal trying to execute itself) and a bunch of other cases that could perhaps arise somewhere. Per bug #15428 from Malthe Borch. Back-patch to all supported branches. Discussion: https://postgr.es/m/15428-b3c2915ec470b033@postgresql.org
* Avoid duplicate XIDs at recovery when building initial snapshotMichael Paquier2018-10-14
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | On a primary, sets of XLOG_RUNNING_XACTS records are generated on a periodic basis to allow recovery to build the initial state of transactions for a hot standby. The set of transaction IDs is created by scanning all the entries in ProcArray. However it happens that its logic never counted on the fact that two-phase transactions finishing to prepare can put ProcArray in a state where there are two entries with the same transaction ID, one for the initial transaction which gets cleared when prepare finishes, and a second, dummy, entry to track that the transaction is still running after prepare finishes. This way ensures a continuous presence of the transaction so as callers of for example TransactionIdIsInProgress() are always able to see it as alive. So, if a XLOG_RUNNING_XACTS takes a standby snapshot while a two-phase transaction finishes to prepare, the record can finish with duplicated XIDs, which is a state expected by design. If this record gets applied on a standby to initial its recovery state, then it would simply fail, so the odds of facing this failure are very low in practice. It would be tempting to change the generation of XLOG_RUNNING_XACTS so as duplicates are removed on the source, but this requires to hold on ProcArrayLock for longer and this would impact all workloads, particularly those using heavily two-phase transactions. XLOG_RUNNING_XACTS is also actually used only to initialize the standby state at recovery, so instead the solution is taken to discard duplicates when applying the initial snapshot. Diagnosed-by: Konstantin Knizhnik Author: Michael Paquier Discussion: https://postgr.es/m/0c96b653-4696-d4b4-6b5d-78143175d113@postgrespro.ru Backpatch-through: 9.3
* Fix logical decoding error when system table w/ toast is repeatedly rewritten.Andres Freund2018-10-10
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Repeatedly rewriting a mapped catalog table with VACUUM FULL or CLUSTER could cause logical decoding to fail with: ERROR, "could not map filenode \"%s\" to relation OID" To trigger the problem the rewritten catalog had to have live tuples with toasted columns. The problem was triggered as during catalog table rewrites the heap_insert() check that prevents logical decoding information to be emitted for system catalogs, failed to treat the new heap's toast table as a system catalog (because the new heap is not recognized as a catalog table via RelationIsLogicallyLogged()). The relmapper, in contrast to the normal catalog contents, does not contain historical information. After a single rewrite of a mapped table the new relation is known to the relmapper, but if the table is rewritten twice before logical decoding occurs, the relfilenode cannot be mapped to a relation anymore. Which then leads us to error out. This only happens for toast tables, because the main table contents aren't re-inserted with heap_insert(). The fix is simple, add a new heap_insert() flag that prevents logical decoding information from being emitted, and accept during decoding that there might not be tuple data for toast tables. Unfortunately that does not fix pre-existing logical decoding errors. Doing so would require not throwing an error when a filenode cannot be mapped to a relation during decoding, and that seems too likely to hide bugs. If it's crucial to fix decoding for an existing slot, temporarily changing the ERROR in ReorderBufferCommit() to a WARNING appears to be the best fix. Author: Andres Freund Discussion: https://postgr.es/m/20180914021046.oi7dm4ra3ot2g2kt@alap3.anarazel.de Backpatch: 9.4-, where logical decoding was introduced
* Silence compiler warning in Assert()Alvaro Herrera2018-10-08
| | | | | | | | gcc 6.3 does not whine about this mistake I made in 39808e8868c8 but evidently lots of other compilers do, according to Michael Paquier, Peter Eisentraut, Arthur Zakirov, Tomas Vondra. Discussion: too many to list
* Fix event triggers for partitioned tablesAlvaro Herrera2018-10-06
| | | | | | | | | | | | | | | | | | Index DDL cascading on partitioned tables introduced a way for ALTER TABLE to be called reentrantly. This caused an an important deficiency in event trigger support to be exposed: on exiting the reentrant call, the alter table state object was clobbered, causing a crash when the outer alter table tries to finalize its processing. Fix the crash by creating a stack of event trigger state objects. There are still ways to cause things to misbehave (and probably other crashers) with more elaborate tricks, but at least it now doesn't crash in the obvious scenario. Backpatch to 9.5, where DDL deparsing of event triggers was introduced. Reported-by: Marco Slot Authors: Michaël Paquier, Álvaro Herrera Discussion: https://postgr.es/m/CANNhMLCpi+HQ7M36uPfGbJZEQLyTy7XvX=5EFkpR-b1bo0uJew@mail.gmail.com
* Propagate xactStartTimestamp and stmtStartTimestamp to parallel workers.Tom Lane2018-10-06
| | | | | | | | | | | | | | | | | | | | | | Previously, a worker process would establish values for these based on its own start time. In v10 and up, this can trivially be shown to cause misbehavior of transaction_timestamp(), timestamp_in(), and related functions which are (perhaps unwisely?) marked parallel-safe. It seems likely that other behaviors might diverge from what happens in the parent as well. It's not as trivial to demonstrate problems in 9.6 or 9.5, but I'm sure it's still possible, so back-patch to all branches containing parallel worker infrastructure. In HEAD only, mark now() and statement_timestamp() as parallel-safe (other affected functions already were). While in theory we could still squeeze that change into v11, it doesn't seem important enough to force a last-minute catversion bump. Konstantin Knizhnik, whacked around a bit by me Discussion: https://postgr.es/m/6406dbd2-5d37-4cb6-6eb2-9c44172c7e7c@postgrespro.ru
* Allow btree comparison functions to return INT_MIN.Tom Lane2018-10-05
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | Historically we forbade datatype-specific comparison functions from returning INT_MIN, so that it would be safe to invert the sort order just by negating the comparison result. However, this was never really safe for comparison functions that directly return the result of memcmp(), strcmp(), etc, as POSIX doesn't place any such restriction on those library functions. Buildfarm results show that at least on recent Linux on s390x, memcmp() actually does return INT_MIN sometimes, causing sort failures. The agreed-on answer is to remove this restriction and fix relevant call sites to not make such an assumption; code such as "res = -res" should be replaced by "INVERT_COMPARE_RESULT(res)". The same is needed in a few places that just directly negated the result of memcmp or strcmp. To help find places having this problem, I've also added a compile option to nbtcompare.c that causes some of the commonly used comparators to return INT_MIN/INT_MAX instead of their usual -1/+1. It'd likely be a good idea to have at least one buildfarm member running with "-DSTRESS_SORT_INT_MIN". That's far from a complete test of course, but it should help to prevent fresh introductions of such bugs. This is a longstanding portability hazard, so back-patch to all supported branches. Discussion: https://postgr.es/m/20180928185215.ffoq2xrq5d3pafna@alap3.anarazel.de
* Fix corner-case failures in has_foo_privilege() family of functions.Tom Lane2018-10-02
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The variants of these functions that take numeric inputs (OIDs or column numbers) are supposed to return NULL rather than failing on bad input; this rule reduces problems with snapshot skew when queries apply the functions to all rows of a catalog. has_column_privilege() had careless handling of the case where the table OID didn't exist. You might get something like this: select has_column_privilege(9999,'nosuchcol','select'); ERROR: column "nosuchcol" of relation "(null)" does not exist or you might get a crash, depending on the platform's printf's response to a null string pointer. In addition, while applying the column-number variant to a dropped column returned NULL as desired, applying the column-name variant did not: select has_column_privilege('mytable','........pg.dropped.2........','select'); ERROR: column "........pg.dropped.2........" of relation "mytable" does not exist It seems better to make this case return NULL as well. Also, the OID-accepting variants of has_foreign_data_wrapper_privilege, has_server_privilege, and has_tablespace_privilege didn't follow the principle of returning NULL for nonexistent OIDs. Superusers got TRUE, everybody else got an error. Per investigation of Jaime Casanova's report of a new crash in HEAD. These behaviors have been like this for a long time, so back-patch to all supported branches. Patch by me; thanks to Stephen Frost for discussion and review Discussion: https://postgr.es/m/CAJGNTeP=-6Gyqq5TN9OvYEydi7Fv1oGyYj650LGTnW44oAzYCg@mail.gmail.com
* Fix ALTER COLUMN TYPE to not open a relation without any lock.Tom Lane2018-10-01
| | | | | | | | | | | | | | | | | | | If the column being modified is referenced by a foreign key constraint of another table, ALTER TABLE would open the other table (to re-parse the constraint's definition) without having first obtained a lock on it. This was evidently intentional, but that doesn't mean it's really safe. It's especially not safe in 9.3, which pre-dates use of MVCC scans for catalog reads, but even in current releases it doesn't seem like a good idea. We know we'll need AccessExclusiveLock shortly to drop the obsoleted constraint, so just get that a little sooner to close the hole. Per testing with a patch that complains if we open a relation without holding any lock on it. I don't plan to back-patch that patch, but we should close the holes it identifies in all supported branches. Discussion: https://postgr.es/m/2038.1538335244@sss.pgh.pa.us
* Fix assertion failure when updating full_page_writes for checkpointer.Amit Kapila2018-09-28
| | | | | | | | | | | | | | | | | | When the checkpointer receives a SIGHUP signal to update its configuration, it may need to update the shared memory for full_page_writes and need to write a WAL record for it. Now, it is quite possible that the XLOG machinery has not been initialized by that time and it will lead to assertion failure while doing that. Fix is to allow the initialization of the XLOG machinery outside critical section. This bug has been introduced by the commit 2c03216d83 which added the XLOG machinery initialization in RecoveryInProgress code path. Reported-by: Dilip Kumar Author: Dilip Kumar Reviewed-by: Michael Paquier and Amit Kapila Backpatch-through: 9.5 Discussion: https://postgr.es/m/CAFiTN-u4BA8KXcQUWDPNgaKAjDXC=C2whnzBM8TAcv=stckYUw@mail.gmail.com
* Fix WAL recycling on standbys depending on archive_modeMichael Paquier2018-09-28
| | | | | | | | | | | | | | | | | | | | | | | | A restart point or a checkpoint recycling WAL segments treats segments marked with neither ".done" (archiving is done) or ".ready" (segment is ready to be archived) in archive_status the same way for archive_mode being "on" or "always". While for a primary this is fine, a standby running a restart point with archive_mode = on would try to mark such a segment as ready for archiving, which is something that will never happen except after the standby is promoted. Note that this problem applies only to WAL segments coming from the local pg_wal the first time archive recovery is run. Segments part of a self-contained base backup are the most common case where this could happen, however even in this case normally the .done markers would be most likely part of the backup. Segments recovered from an archive are marked as .ready or .done by the startup process, and segments finished streaming are marked as such by the WAL receiver, so they are handled already. Reported-by: Haruka Takatsuka Author: Michael Paquier Discussion: https://postgr.es/m/15402-a453c90ed4cf88b2@postgresql.org Backpatch-through: 9.5, where archive_mode = always has been added.
* Recurse to sequences on ownership change for all relkindsPeter Eisentraut2018-09-26
| | | | | | | | | | | | | | When a table ownership is changed, we must apply that also to any owned sequences. (Otherwise, it would result in a situation that cannot be restored, because linked sequences must have the same owner as the table.) But this was previously only applied to regular tables and materialized views. But it should also apply to at least foreign tables. This patch removes the relkind check altogether, because it doesn't save very much and just introduces the possibility of similar omissions. Bug: #15238 Reported-by: Christoph Berg <christoph.berg@credativ.de>
* Rework activation of commit timestamps during recoveryMichael Paquier2018-09-26
| | | | | | | | | | | | | | | | | | | | | | | | | | The activation and deactivation of commit timestamp tracking has not been handled consistently for a primary or standbys at recovery. The facility can be activated at three different moments of recovery: - The beginning, where a primary would use the GUC value for the decision-making, and where a standby relies on the contents of the control file. - When replaying a XLOG_PARAMETER_CHANGE record at redo. - The end, where both primary and standby rely on the GUC value. Using the GUC value for a primary at the beginning of recovery causes problems with commit timestamp access when doing crash recovery. Particularly, when replaying transaction commits, it could be possible that an attempt to read commit timestamps is done for a transaction which committed at a moment when track_commit_timestamp was disabled. A test case is added to reproduce the failure. The test works down to v11 as it takes advantage of transaction commits within procedures. Reported-by: Hailong Li Author: Masahiko Sawasa, Michael Paquier Reviewed-by: Kyotaro Horiguchi Discussion: https://postgr.es/m/11224478-a782-203b-1f17-e4797b39bdf0@qunar.com Backpatch-through: 9.5, where commit timestamps have been introduced.
* Fix over-allocation of space for array_out()'s result string.Tom Lane2018-09-24
| | | | | | | | | | | | | | | | | | | | | | | | array_out overestimated the space needed for its output, possibly by a very substantial amount if the array is multi-dimensional, because of wrong order of operations in the loop that counts the number of curly-brace pairs needed. While the output string is normally short-lived, this could still cause problems in extreme cases. An additional minor error was that it counted one more delimiter than is actually needed. Repair those errors, add an Assert that the space is now correctly calculated, and make some minor improvements in the comments. I also failed to resist the temptation to get rid of an integer modulus operation per array element; a simple comparison is sufficient. This bug dates clear back to Berkeley days, so back-patch to all supported versions. Keiichi Hirobe, minor additional work by me Discussion: https://postgr.es/m/CAH=EFxE9W0tRvQkixR2XJRRCToUYUEDkJZk6tnADXugPBRdcdg@mail.gmail.com
* Initialize random() in bootstrap/stand-alone postgres and in initdb.Noah Misch2018-09-23
| | | | | | | | | | | | | | | | | | | | | | This removes a difference between the standard IsUnderPostmaster execution environment and that of --boot and --single. In a stand-alone backend, "SELECT random()" always started at the same seed. On a system capable of using posix shared memory, initdb could still conclude "selecting dynamic shared memory implementation ... sysv". Crashed --boot or --single postgres processes orphaned shared memory objects having names that collided with the not-actually-random names that initdb probed. The sysv fallback appeared after ten crashes of --boot or --single postgres. Since --boot and --single are rare in production use, systems used for PostgreSQL development are the principal candidate to notice this symptom. Back-patch to 9.3 (all supported versions). PostgreSQL 9.4 introduced dynamic shared memory, but 9.3 does share the "SELECT random()" problem. Reviewed by Tom Lane and Kyotaro HORIGUCHI. Discussion: https://postgr.es/m/20180915221546.GA3159382@rfd.leadboat.com
* Fix failure in WHERE CURRENT OF after rewinding the referenced cursor.Tom Lane2018-09-23
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | In a case where we have multiple relation-scan nodes in a cursor plan, such as a scan of an inheritance tree, it's possible to fetch from a given scan node, then rewind the cursor and fetch some row from an earlier scan node. In such a case, execCurrent.c mistakenly thought that the later scan node was still active, because ExecReScan hadn't done anything to make it look not-active. We'd get some sort of failure in the case of a SeqScan node, because the node's scan tuple slot would be pointing at a HeapTuple whose t_self gets reset to invalid by heapam.c. But it seems possible that for other relation scan node types we'd actually return a valid tuple TID to the caller, resulting in updating or deleting a tuple that shouldn't have been considered current. To fix, forcibly clear the ScanTupleSlot in ExecScanReScan. Another issue here, which seems only latent at the moment but could easily become a live bug in future, is that rewinding a cursor does not necessarily lead to *immediately* applying ExecReScan to every scan-level node in the plan tree. Upper-level nodes will think that they can postpone that call if their child node is already marked with chgParam flags. I don't see a way for that to happen today in a plan tree that's simple enough for execCurrent.c's search_plan_tree to understand, but that's one heck of a fragile assumption. So, add some logic in search_plan_tree to detect chgParam flags being set on nodes that it descended to/through, and assume that that means we should consider lower scan nodes to be logically reset even if their ReScan call hasn't actually happened yet. Per bug #15395 from Matvey Arye. This has been broken for a long time, so back-patch to all supported branches. Discussion: https://postgr.es/m/153764171023.14986.280404050547008575@wrigleys.postgresql.org
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