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2021-06-13Further tweaks to stuck_on_old_timeline recovery testAndrew Dunstan
Translate path slashes on target directory path. This was confusing old branches, but is applied to all branches for the sake of uniformity. Perl is perfectly able to understand paths with forward slashes. Along the way, restore the previous archive_wait query, for the sake of uniformity with other tests, per gripe from Tom Lane.
2021-06-13Ignore more environment variables in pg_regress.cMichael Paquier
This is similar to the work done in 8279f68 for TestLib.pm, where environment variables set may cause unwanted failures if using a temporary installation with pg_regress. The list of variables reset is adjusted in each stable branch depending on what is supported. Comments are added to remember that the lists in TestLib.pm and pg_regress.c had better be kept in sync. Reviewed-by: Álvaro Herrera Discussion: https://postgr.es/m/YMNR9GYDn+fHlMta@paquier.xyz Backpatch-through: 9.6
2021-06-12Restore robustness of TAP tests that wait for postmaster restart.Tom Lane
Several TAP tests use poll_query_until() to wait for the postmaster to restart. They were checking to see if a trivial query (e.g. "SELECT 1") succeeds. However, that's problematic in the wake of commit 11e9caff8, because now that we feed said query to psql via stdin, we risk IPC::Run whining about a SIGPIPE failure if psql quits before reading the query. Hence, we can't use a nonempty query in cases where we need to wait for connection failures to stop happening. Per the precedent of commits c757a3da0 and 6d41dd045, we can pass "undef" as the query in such cases to ensure that IPC::Run has nothing to write. However, then we have to say that the expected output is empty, and this exposes a deficiency in poll_query_until: if psql fails altogether and returns empty stdout, poll_query_until will treat that as a success! That's because, contrary to its documentation, it makes no actual check for psql failure, looking neither at the exit status nor at stderr. To fix that, adjust poll_query_until to insist on empty stderr as well as a stdout match. (I experimented with checking exit status instead, but it seems that psql often does exit(1) in cases that we need to consider successes. That might be something to fix someday, but it would be a non-back-patchable behavior change.) Back-patch to v10. The test cases needing this exist only as far back as v11, but it seems wise to keep poll_query_until's behavior the same in v10, in case we back-patch another such test case in future. (9.6 does not currently need this change, because in that branch poll_query_until can't be told to accept empty stdout as a success case.) Per assorted buildfarm failures, mostly on hoverfly. Discussion: https://postgr.es/m/CAA4eK1+zM6L4QSA1XMvXY_qqWwdUmqkOS1+hWvL8QcYEBGA1Uw@mail.gmail.com
2021-06-12Ensure pg_filenode_relation(0, 0) returns NULL.Tom Lane
Previously, a zero value for the relfilenode resulted in a confusing error message about "unexpected duplicate". This function returns NULL for other invalid relfilenode values, so zero should be treated likewise. It's been like this all along, so back-patch to all supported branches. Justin Pryzby Discussion: https://postgr.es/m/20210612023324.GT16435@telsasoft.com
2021-06-12Don't use Asserts to check for violations of replication protocol.Tom Lane
Using an Assert to check the validity of incoming messages is an extremely poor decision. In a debug build, it should not be that easy for a broken or malicious remote client to crash the logrep worker. The consequences could be even worse in non-debug builds, which will fail to make such checks at all, leading to who-knows-what misbehavior. Hence, promote every Assert that could possibly be triggered by wrong or out-of-order replication messages to a full test-and-ereport. To avoid bloating the set of messages the translation team has to cope with, establish a policy that replication protocol violation error reports don't need to be translated. Hence, all the new messages here use errmsg_internal(). A couple of old messages are changed likewise for consistency. Along the way, fix some non-idiomatic or outright wrong uses of hash_search(). Most of these mistakes are new with the "streaming replication" patch (commit 464824323), but a couple go back a long way. Back-patch as appropriate. Discussion: https://postgr.es/m/1719083.1623351052@sss.pgh.pa.us
2021-06-12Fix new recovery test for use under msysAndrew Dunstan
Commit caba8f0d43 wasn't quite right for msys, as demonstrated by several buildfarm animals, including jacana and fairywren. We need to use the msys perl in the archive command, but call it in such a way that Windows will understand the path. Furthermore, inside the copy script we need to convert a Windows path to an msys path.
2021-06-12Remove PGSSLCRLDIR from the list of variables ignored in TAP testsMichael Paquier
This variable was present in the list added by 9d660670, but it is not supported by this branch. Issue noticed while diving into a similar change for pg_regress.c. Backpatch-through: 9.6
2021-06-11Report sort phase progress in parallel btree buildAlvaro Herrera
We were already reporting it, but only after the parallel workers were finished, which is visibly much later than what happens in a serial build. With this change we report it when the leader starts its own sort phase when participating in the build (the normal case). Now this might happen a little later than when the workers start their sorting phases, but a) communicating the actual phase start from workers is likely to be a hassle, and b) the sort phase start is pretty fuzzy anyway, since sorting per se is actually initiated by tuplesort.c internally earlier than tuplesort_performsort() is called. Backpatch to pg12, where the progress reporting code for CREATE INDEX went in. Reported-by: Tomas Vondra <tomas.vondra@enterprisedb.com> Author: Matthias van de Meent <boekewurm+postgres@gmail.com> Reviewed-by: Greg Nancarrow <gregn4422@gmail.com> Reviewed-by: Álvaro Herrera <alvherre@alvh.no-ip.org> Discussion: https://postgr.es/m/1128176d-1eee-55d4-37ca-e63644422adb
2021-06-10Rearrange logrep worker's snapshot handling some more.Tom Lane
It turns out that worker.c's code path for TRUNCATE was also careless about establishing a snapshot while executing user-defined code, allowing the checks added by commit 84f5c2908 to fail when a trigger is fired in that context. We could just wrap Push/PopActiveSnapshot around the truncate call, but it seems better to establish a policy of holding a snapshot throughout execution of a replication step. To help with that and possible future requirements, replace the previous ensure_transaction calls with pairs of begin/end_replication_step calls. Per report from Mark Dilger. Back-patch to v11, like the previous changes. Discussion: https://postgr.es/m/B4A3AF82-79ED-4F4C-A4E5-CD2622098972@enterprisedb.com
2021-06-10Adjust new test case to set wal_keep_segments.Robert Haas
Per buildfarm member conchuela and Kyotaro Horiguchi, it's possible for the WAL segment that the cascading standby needs to be removed too quickly. Hopefully this will prevent that. Kyotaro Horiguchi Discussion: http://postgr.es/m/20210610.101240.1270925505780628275.horikyota.ntt@gmail.com
2021-06-09Fix corner case failure of new standby to follow new primary.Robert Haas
This only happens if (1) the new standby has no WAL available locally, (2) the new standby is starting from the old timeline, (3) the promotion happened in the WAL segment from which the new standby is starting, (4) the timeline history file for the new timeline is available from the archive but the WAL files for are not (i.e. this is a race), (5) the WAL files for the new timeline are available via streaming, and (6) recovery_target_timeline='latest'. Commit ee994272ca50f70b53074f0febaec97e28f83c4e introduced this logic and was an improvement over the previous code, but it mishandled this case. If recovery_target_timeline='latest' and restore_command is set, validateRecoveryParameters() can change recoveryTargetTLI to be different from receiveTLI. If streaming is then tried afterward, expectedTLEs gets initialized with the history of the wrong timeline. It's supposed to be a list of entries explaining how to get to the target timeline, but in this case it ends up with a list of entries explaining how to get to the new standby's original timeline, which isn't right. Dilip Kumar and Robert Haas, reviewed by Kyotaro Horiguchi. Discussion: http://postgr.es/m/CAFiTN-sE-jr=LB8jQuxeqikd-Ux+jHiXyh4YDiZMPedgQKup0g@mail.gmail.com
2021-06-09Allow PostgresNode.pm's backup method to accept backup_options.Robert Haas
Partial back-port of commit 081876d75ea15c3bd2ee5ba64a794fd8ea46d794. A test case for a pending bug fix needs this capability, but the code on 9.6 is significantly different, so I'm only back-patching this change as far as v10. We'll have to work around the problem another way in v9.6. Discussion: http://postgr.es/m/CAFiTN-tcivNvL0Rg6rD7_CErNfE75H7+gh9WbMxjbgsattja1Q@mail.gmail.com
2021-06-09Fix inconsistencies in psql --help=commandsMichael Paquier
The set of subcommands supported by \dAp, \do and \dy was described incorrectly in psql's --help. The documentation was already consistent with the code. Reported-by: inoas, from IRC Author: Matthijs van der Vleuten Reviewed-by: Neil Chen Discussion: https://postgr.es/m/6a984e24-2171-4039-9050-92d55e7b23fe@www.fastmail.com Backpatch-through: 9.6
2021-06-08Force NO SCROLL for plpgsql's implicit cursors.Tom Lane
Further thought about bug #17050 suggests that it's a good idea to use CURSOR_OPT_NO_SCROLL for the implicit cursor opened by a plpgsql FOR-over-query loop. This ensures that, if somebody commits inside the loop, PersistHoldablePortal won't try to rewind and re-read the cursor. While we'd have selected NO_SCROLL anyway if FOR UPDATE/SHARE appears in the query, there are other hazards with volatile functions; and in any case, it's silly to expend effort storing rows that we know for certain won't be needed. (While here, improve the comment in exec_run_select, which was a bit confused about the rationale for when we can use parallel mode. Cursor operations aren't a hazard for nameless portals.) This wasn't an issue until v11, which introduced the possibility of persisting such cursors. Hence, back-patch to v11. Per bug #17050 from Алексей Булгаков. Discussion: https://postgr.es/m/17050-f77aa827dc85247c@postgresql.org
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
2021-06-08Remove unnecessary declaration in win32_port.hMichael Paquier
Mis-merge introduced by e2f21ff, where pgwin32_setenv() was listed but not defined in win32env.c. This had no consequences as this routine does not exist in this branch. Only REL_12_STABLE and REL_13_STABLE got that wrong. Backpatch-through: 12
2021-06-07Stabilize contrib/seg regression test.Tom Lane
If autovacuum comes along just after we fill table test_seg with some data, it will update the stats to the point where we prefer a plain indexscan over a bitmap scan, breaking the expected output (as well as the point of the test case). To fix, just force a bitmap scan to be chosen here. This has evidently been wrong since commit de1d042f5. It's not clear why we just recently saw any buildfarm failures due to it; but prairiedog has failed twice on this test in the past week. Hence, backpatch to v11 where this test case came in.
2021-06-07Fix incautious handling of possibly-miscoded strings in client code.Tom Lane
An incorrectly-encoded multibyte character near the end of a string could cause various processing loops to run past the string's terminating NUL, with results ranging from no detectable issue to a program crash, depending on what happens to be in the following memory. This isn't an issue in the server, because we take care to verify the encoding of strings before doing any interesting processing on them. However, that lack of care leaked into client-side code which shouldn't assume that anyone has validated the encoding of its input. Although this is certainly a bug worth fixing, the PG security team elected not to regard it as a security issue, primarily because any untrusted text should be sanitized by PQescapeLiteral or the like before being incorporated into a SQL or psql command. (If an app fails to do so, the same technique can be used to cause SQL injection, with probably much more dire consequences than a mere client-program crash.) Those functions were already made proof against this class of problem, cf CVE-2006-2313. To fix, invent PQmblenBounded() which is like PQmblen() except it won't return more than the number of bytes remaining in the string. In HEAD we can make this a new libpq function, as PQmblen() is. It seems imprudent to change libpq's API in stable branches though, so in the back branches define PQmblenBounded as a macro in the files that need it. (Note that just changing PQmblen's behavior would not be a good idea; notably, it would completely break the escaping functions' defense against this exact problem. So we just want a version for those callers that don't have any better way of handling this issue.) Per private report from houjingyi. Back-patch to all supported branches.
2021-06-05Remove leftover conflict markerPeter Eisentraut
2021-06-03In PostgresNode.pm, don't pass SQL to psql on the command lineAndrew Dunstan
The Msys shell mangles certain patterns in its command line, so avoid handing arbitrary SQL to psql on the command line and instead use IPC::Run's redirection facility for stdin. This pattern is already mostly whats used, but query_poll_until() was not doing the right thing. Problem discovered on the buildfarm when a new TAP test failed on msys.
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
2021-06-03Ignore more environment variables in TAP testsMichael Paquier
Various environment variables were not getting reset in the TAP tests, which would cause failures depending on the tests or the environment variables involved. For example, PGSSL{MAX,MIN}PROTOCOLVERSION could cause failures in the SSL tests. Even worse, a junk value of PGCLIENTENCODING makes a server startup fail. The list of variables reset is adjusted in each stable branch depending on what is supported. While on it, simplify a bit the code per a suggestion from Andrew Dunstan, using a list of variables instead of doing single deletions. Reviewed-by: Andrew Dunstan, Daniel Gustafsson Discussion: https://postgr.es/m/YLbjjRpucIeZ78VQ@paquier.xyz Backpatch-through: 9.6
2021-06-02Fix planner's row-mark code for inheritance from a foreign table.Tom Lane
Commit 428b260f8 broke planning of cases where row marks are needed (SELECT FOR UPDATE, etc) and one of the query's tables is a foreign table that has regular table(s) as inheritance children. We got the reverse case right, but apparently were thinking that foreign tables couldn't be inheritance parents. Not so; so we need to be able to add a CTID junk column while adding a new child, not only a wholerow junk column. Back-patch to v12 where the faulty code came in. Amit Langote Discussion: https://postgr.es/m/CA+HiwqEmo3FV1LAQ4TVyS2h1WM=kMkZUmbNuZSCnfHvMcUcPeA@mail.gmail.com
2021-06-01Reject SELECT ... GROUP BY GROUPING SETS (()) FOR UPDATE.Tom Lane
This case should be disallowed, just as FOR UPDATE with a plain GROUP BY is disallowed; FOR UPDATE only makes sense when each row of the query result can be identified with a single table row. However, we missed teaching CheckSelectLocking() to check groupingSets as well as groupClause, so that it would allow degenerate grouping sets. That resulted in a bad plan and a null-pointer dereference in the executor. Looking around for other instances of the same bug, the only one I found was in examine_simple_variable(). That'd just lead to silly estimates, but it should be fixed too. Per private report from Yaoguang Chen. Back-patch to all supported branches.
2021-06-01Add fallback implementation for setenv()Michael Paquier
This fixes the code compilation on Windows with MSVC and Kerberos, as a missing implementation of setenv() causes a compilation failure of the GSSAPI code. This was only reproducible when building the code with Kerberos, something that buildfarm animal hamerkop has fixed recently. This issue only happens on 12 and 13, as this code has been introduced in b0b39f7. HEAD is already able to compile properly thanks to 7ca37fb0, and this commit is a minimal cherry-pick of it. Thanks to Tom Lane for the discussion. Discussion: https://postgr.es/m/YLDtm5WGjPxm6ua4@paquier.xyz Backpatch-through: 12
2021-05-31Fix mis-planning of repeated application of a projection.Tom Lane
create_projection_plan contains a hidden assumption (here made explicit by an Assert) that a projection-capable Path will yield a projection-capable Plan. Unfortunately, that assumption is violated only a few lines away, by create_projection_plan itself. This means that two stacked ProjectionPaths can yield an outcome where we try to jam the upper path's tlist into a non-projection-capable child node, resulting in an invalid plan. There isn't any good reason to have stacked ProjectionPaths; indeed the whole concept is faulty, since the set of Vars/Aggs/etc needed by the upper one wouldn't necessarily be available in the output of the lower one, nor could the lower one create such values if they weren't available from its input. Hence, we can fix this by adjusting create_projection_path to strip any top-level ProjectionPath from the subpath it's given. (This amounts to saying "oh, we changed our minds about what we need to project here".) The test case added here only fails in v13 and HEAD; before that, we don't attempt to shove the Sort into the parallel part of the plan, for reasons that aren't entirely clear to me. However, all the directly-related code looks generally the same as far back as v11, where the hazard was introduced (by d7c19e62a). So I've got no faith that the same type of bug doesn't exist in v11 and v12, given the right test case. Hence, back-patch the code changes, but not the irrelevant test case, into those branches. Per report from Bas Poot. Discussion: https://postgr.es/m/534fca83789c4a378c7de379e9067d4f@politie.nl
2021-05-31Raise a timeout to 180s, in test 010_logical_decoding_timelines.pl.Noah Misch
Per buildfarm member hornet. Also, update Pod documentation showing the lower value. Back-patch to v10, where the test first appeared.
2021-05-29Fix race condition when sharing tuple descriptors.Thomas Munro
Parallel query processes that called BlessTupleDesc() for identical tuple descriptors at the same moment could crash. There was code to handle that rare case, but it dereferenced a bogus DSA pointer. Repair. Back-patch to 11, where commit cc5f8136 added support for sharing tuple descriptors in parallel queries. Reported-by: Eric Thinnes <e.thinnes@gmx.de> Discussion: https://postgr.es/m/99aaa2eb-e194-bf07-c29a-1a76b4f2bcf9%40gmx.de
2021-05-28fix syntax errorAndrew Dunstan
2021-05-28Report configured port in MSVC built pg_configAndrew Dunstan
This is a long standing omission, discovered when trying to write code that relied on it. Backpatch to all live branches.
2021-05-27Fix MSVC scripts when building with GSSAPI/KerberosMichael Paquier
The deliverables of upstream Kerberos on Windows are installed with paths that do not match our MSVC scripts. First, the include folder was named "inc/" in our scripts, but the upstream MSIs use "include/". Second, the build would fail with 64-bit environments as the libraries are named differently. This commit adjusts the MSVC scripts to be compatible with the latest installations of upstream, and I have checked that the compilation was able to work with the 32-bit and 64-bit installations. Special thanks to Kondo Yuta for the help in investigating the situation in hamerkop, which had an incorrect configuration for the GSS compilation. Reported-by: Brian Ye Discussion: https://postgr.es/m/162128202219.27274.12616756784952017465@wrigleys.postgresql.org Backpatch-through: 9.6
2021-05-27doc: Fix description of some GUCs in docs and postgresql.conf.sampleMichael Paquier
The following parameters have been imprecise, or incorrect, about their description (PGC_POSTMASTER or PGC_SIGHUP): - autovacuum_work_mem (docs, as of 9.6~) - huge_page_size (docs, as of 14~) - max_logical_replication_workers (docs, as of 10~) - max_sync_workers_per_subscription (docs, as of 10~) - min_dynamic_shared_memory (docs, as of 14~) - recovery_init_sync_method (postgresql.conf.sample, as of 14~) - remove_temp_files_after_crash (docs, as of 14~) - restart_after_crash (docs, as of 9.6~) - ssl_min_protocol_version (docs, as of 12~) - ssl_max_protocol_version (docs, as of 12~) This commit adjusts the description of all these parameters to be more consistent with the practice used for the others. Revewed-by: Justin Pryzby Discussion: https://postgr.es/m/YK2ltuLpe+FbRXzA@paquier.xyz Backpatch-through: 9.6
2021-05-25Disallow SSL renegotiationMichael Paquier
SSL renegotiation is already disabled as of 48d23c72, however this does not prevent the server to comply with a client willing to use renegotiation. In the last couple of years, renegotiation had its set of security issues and flaws (like the recent CVE-2021-3449), and it could be possible to crash the backend with a client attempting renegotiation. This commit takes one extra step by disabling renegotiation in the backend in the same way as SSL compression (f9264d15) or tickets (97d3a0b0). OpenSSL 1.1.0h has added an option named SSL_OP_NO_RENEGOTIATION able to achieve that. In older versions there is an option called SSL3_FLAGS_NO_RENEGOTIATE_CIPHERS that was undocumented, and could be set within the SSL object created when the TLS connection opens, but I have decided not to use it, as it feels trickier to rely on, and it is not official. Note that this option is not usable in OpenSSL < 1.1.0h as the internal contents of the *SSL object are hidden to applications. SSL renegotiation concerns protocols up to TLSv1.2. Per original report from Robert Haas, with a patch based on a suggestion by Andres Freund. Author: Michael Paquier Reviewed-by: Daniel Gustafsson Discussion: https://postgr.es/m/YKZBXx7RhU74FlTE@paquier.xyz Backpatch-through: 9.6
2021-05-21Disallow whole-row variables in GENERATED expressions.Tom Lane
This was previously allowed, but I think that was just an oversight. It's a clear violation of the rule that a generated column cannot depend on itself or other generated columns. Moreover, because the code was relying on the assumption that no such cross-references exist, it was pretty easy to crash ALTER TABLE and perhaps other places. Even if you managed not to crash, you got quite unstable, implementation-dependent results. Per report from Vitaly Ustinov. Back-patch to v12 where GENERATED came in. Discussion: https://postgr.es/m/CAM_DEiWR2DPT6U4xb-Ehigozzd3n3G37ZB1+867zbsEVtYoJww@mail.gmail.com
2021-05-21Fix 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
2021-05-21Fix deadlock for multiple replicating truncates of the same table.Amit Kapila
While applying the truncate change, the logical apply worker acquires RowExclusiveLock on the relation being truncated. This allowed truncate on the relation at a time by two apply workers which lead to a deadlock. The reason was that one of the workers after updating the pg_class tuple tries to acquire SHARE lock on the relation and started to wait for the second worker which has acquired RowExclusiveLock on the relation. And when the second worker tries to update the pg_class tuple, it starts to wait for the first worker which leads to a deadlock. Fix it by acquiring AccessExclusiveLock on the relation before applying the truncate change as we do for normal truncate operation. Author: Peter Smith, test case by Haiying Tang Reviewed-by: Dilip Kumar, Amit Kapila Backpatch-through: 11 Discussion: https://postgr.es/m/CAHut+PsNm43p0jM+idTvWwiGZPcP0hGrHMPK9TOAkc+a4UpUqw@mail.gmail.com
2021-05-20Avoid detoasting failure after COMMIT inside a plpgsql FOR loop.Tom Lane
exec_for_query() normally tries to prefetch a few rows at a time from the query being iterated over, so as to reduce executor entry/exit overhead. Unfortunately this is unsafe if we have COMMIT or ROLLBACK within the loop, because there might be TOAST references in the data that we prefetched but haven't yet examined. Immediately after the COMMIT/ROLLBACK, we have no snapshots in the session, meaning that VACUUM is at liberty to remove recently-deleted TOAST rows. This was originally reported as a case triggering the "no known snapshots" error in init_toast_snapshot(), but even if you miss hitting that, you can get "missing toast chunk", as illustrated by the added isolation test case. To fix, just disable prefetching in non-atomic contexts. Maybe there will be performance complaints prompting us to work harder later, but it's not clear at the moment that this really costs much, and I doubt we'd want to back-patch any complicated fix. In passing, adjust that error message in init_toast_snapshot() to be a little clearer about the likely cause of the problem. Patch by me, based on earlier investigation by Konstantin Knizhnik. 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
2021-05-20Clean up cpluspluscheck violation.Tom Lane
"typename" is a C++ keyword, so pg_upgrade.h fails to compile in C++. Fortunately, there seems no likely reason for somebody to need to do that. Nonetheless, it's project policy that all .h files should pass cpluspluscheck, so rename the argument to fix that. Oversight in 57c081de0; back-patch as that was. (The policy requiring pg_upgrade.h to pass cpluspluscheck only goes back to v12, but it seems best to keep this code looking the same in all branches.)
2021-05-18Fix typo and outdated information in README.barrierDavid Rowley
README.barrier didn't seem to get the memo when atomics were added. Fix that. Author: Tatsuo Ishii, David Rowley Discussion: https://postgr.es/m/20210516.211133.2159010194908437625.t-ishii%40sraoss.co.jp Backpatch-through: 9.6, oldest supported release
2021-05-15Be more careful about barriers when releasing BackgroundWorkerSlots.Tom Lane
ForgetBackgroundWorker lacked any memory barrier at all, while BackgroundWorkerStateChange had one but unaccountably did additional manipulation of the slot after the barrier. AFAICS, the rule must be that the barrier is immediately before setting or clearing slot->in_use. It looks like back in 9.6 when ForgetBackgroundWorker was first written, there might have been some case for not needing a barrier there, but I'm not very convinced of that --- the fact that the load of bgw_notify_pid is in the caller doesn't seem to guarantee no memory ordering problem. So patch 9.6 too. It's likely that this doesn't fix any observable bug on Intel hardware, but machines with weaker memory ordering rules could have problems here. Discussion: https://postgr.es/m/4046084.1620244003@sss.pgh.pa.us
2021-05-14Doc: correct erroneous entry in this week's minor release notes.Tom Lane
The patch to disallow a NULL specification in combination with GENERATED ... AS IDENTITY applied to both ALWAYS and BY DEFAULT variants of that clause, not only the former. Noted by Shay Rojansky. Discussion: https://postgr.es/m/CADT4RqAwD3A=RvGiQU9AiTK-6VeuXcycwPHmJPv_OBCJFYOEww@mail.gmail.com
2021-05-14Prevent infinite insertion loops in spgdoinsert().Tom Lane
Formerly we just relied on operator classes that assert longValuesOK to eventually shorten the leaf value enough to fit on an index page. That fails since the introduction of INCLUDE-column support (commit 09c1c6ab4), because the INCLUDE columns might alone take up more than a page, meaning no amount of leaf-datum compaction will get the job done. At least with spgtextproc.c, that leads to an infinite loop, since spgtextproc.c won't throw an error for not being able to shorten the leaf datum anymore. To fix without breaking cases that would otherwise work, add logic to spgdoinsert() to verify that the leaf tuple size is decreasing after each "choose" step. Some opclasses might not decrease the size on every single cycle, and in any case, alignment roundoff of the tuple size could obscure small gains. Therefore, allow up to 10 cycles without additional savings before throwing an error. (Perhaps this number will need adjustment, but it seems quite generous right now.) As long as we've developed this logic, let's back-patch it. The back branches don't have INCLUDE columns to worry about, but this seems like a good defense against possible bugs in operator classes. We already know that an infinite loop here is pretty unpleasant, so having a defense seems to outweigh the risk of breaking things. (Note that spgtextproc.c is actually the only known opclass with longValuesOK support, so that this is all moot for known non-core opclasses anyway.) Per report from Dilip Kumar. Discussion: https://postgr.es/m/CAFiTN-uxP_soPhVG840tRMQTBmtA_f_Y8N51G7DKYYqDh7XN-A@mail.gmail.com
2021-05-14Fix query-cancel handling in spgdoinsert().Tom Lane
Knowing that a buggy opclass could cause an infinite insertion loop, spgdoinsert() intended to allow its loop to be interrupted by query cancel. However, that never actually worked, because in iterations after the first, we'd be holding buffer lock(s) which would cause InterruptHoldoffCount to be positive, preventing servicing of the interrupt. To fix, check if an interrupt is pending, and if so fall out of the insertion loop and service the interrupt after we've released the buffers. If it was indeed a query cancel, that's the end of the matter. If it was a non-canceling interrupt reason, make use of the existing provision to retry the whole insertion. (This isn't as wasteful as it might seem, since any upper-level index tuples we already created should be usable in the next attempt.) While there's no known instance of such a bug in existing release branches, it still seems like a good idea to back-patch this to all supported branches, since the behavior is fairly nasty if a loop does happen --- not only is it uncancelable, but it will quickly consume memory to the point of an OOM failure. In any case, this code is certainly not working as intended. Per report from Dilip Kumar. Discussion: https://postgr.es/m/CAFiTN-uxP_soPhVG840tRMQTBmtA_f_Y8N51G7DKYYqDh7XN-A@mail.gmail.com
2021-05-14Refactor CHECK_FOR_INTERRUPTS() to add flexibility.Tom Lane
Split up CHECK_FOR_INTERRUPTS() to provide an additional macro INTERRUPTS_PENDING_CONDITION(), which just tests whether an interrupt is pending without attempting to service it. This is useful in situations where the caller knows that interrupts are blocked, and would like to find out if it's worth the trouble to unblock them. Also add INTERRUPTS_CAN_BE_PROCESSED(), which indicates whether CHECK_FOR_INTERRUPTS() can be relied on to clear the pending interrupt. This commit doesn't actually add any uses of the new macros, but a follow-on bug fix will do so. Back-patch to all supported branches to provide infrastructure for that fix. Alvaro Herrera and Tom Lane Discussion: https://postgr.es/m/20210513155351.GA7848@alvherre.pgsql
2021-05-13Improve documentation example for jsonpath like_regex operatorAlexander Korotkov
Make sample like_regex match string values of the root object instead of the whole document. The corrected example seems to represent a more relevant use case. Backpatch to 12, when jsonpath was introduced. Discussion: https://postgr.es/m/13440f8b-4c1f-5875-c8e3-f3f65606af2f%40xs4all.nl Author: Erik Rijkers Reviewed-by: Michael Paquier, Alexander Korotkov Backpatch-through: 12
2021-05-12Rename the logical replication global "wrconn"Alvaro Herrera
The worker.c global wrconn is only meant to be used by logical apply/ tablesync workers, but there are other variables with the same name. To reduce future confusion rename the global from "wrconn" to "LogRepWorkerWalRcvConn". While this is just cosmetic, it seems better to backpatch it all the way back to 10 where this code appeared, to avoid future backpatching issues. Author: Peter Smith <smithpb2250@gmail.com> Discussion: https://postgr.es/m/CAHut+Pu7Jv9L2BOEx_Z0UtJxfDevQSAUW2mJqWU+CtmDrEZVAg@mail.gmail.com
2021-05-10Stamp 12.7.REL_12_7Tom Lane
2021-05-10Last-minute updates for release notes.Tom Lane
Security: CVE-2021-32027, CVE-2021-32028, CVE-2021-32029
2021-05-10Fix mishandling of resjunk columns in ON CONFLICT ... UPDATE tlists.Tom Lane
It's unusual to have any resjunk columns in an ON CONFLICT ... UPDATE list, but it can happen when MULTIEXPR_SUBLINK SubPlans are present. If it happens, the ON CONFLICT UPDATE code path would end up storing tuples that include the values of the extra resjunk columns. That's fairly harmless in the short run, but if new columns are added to the table then the values would become accessible, possibly leading to malfunctions if they don't match the datatypes of the new columns. This had escaped notice through a confluence of missing sanity checks, including * There's no cross-check that a tuple presented to heap_insert or heap_update matches the table rowtype. While it's difficult to check that fully at reasonable cost, we can easily add assertions that there aren't too many columns. * The output-column-assignment cases in execExprInterp.c lacked any sanity checks on the output column numbers, which seems like an oversight considering there are plenty of assertion checks on input column numbers. Add assertions there too. * We failed to apply nodeModifyTable's ExecCheckPlanOutput() to the ON CONFLICT UPDATE tlist. That wouldn't have caught this specific error, since that function is chartered to ignore resjunk columns; but it sure seems like a bad omission now that we've seen this bug. In HEAD, the right way to fix this is to make the processing of ON CONFLICT UPDATE tlists work the same as regular UPDATE tlists now do, that is don't add "SET x = x" entries, and use ExecBuildUpdateProjection to evaluate the tlist and combine it with old values of the not-set columns. This adds a little complication to ExecBuildUpdateProjection, but allows removal of a comparable amount of now-dead code from the planner. In the back branches, the most expedient solution seems to be to (a) use an output slot for the ON CONFLICT UPDATE projection that actually matches the target table, and then (b) invent a variant of ExecBuildProjectionInfo that can be told to not store values resulting from resjunk columns, so it doesn't try to store into nonexistent columns of the output slot. (We can't simply ignore the resjunk columns altogether; they have to be evaluated for MULTIEXPR_SUBLINK to work.) This works back to v10. In 9.6, projections work much differently and we can't cheaply give them such an option. The 9.6 version of this patch works by inserting a JunkFilter when it's necessary to get rid of resjunk columns. In addition, v11 and up have the reverse problem when trying to perform ON CONFLICT UPDATE on a partitioned table. Through a further oversight, adjust_partition_tlist() discarded resjunk columns when re-ordering the ON CONFLICT UPDATE tlist to match a partition. This accidentally prevented the storing-bogus-tuples problem, but at the cost that MULTIEXPR_SUBLINK cases didn't work, typically crashing if more than one row has to be updated. Fix by preserving resjunk columns in that routine. (I failed to resist the temptation to add more assertions there too, and to do some minor code beautification.) Per report from Andres Freund. Back-patch to all supported branches. Security: CVE-2021-32028