The SIGTERM handler for the startup process immediately calls
proc_exit() for the duration of the restore_command, i.e., a call
to system(). This system() call forks a new process to execute the
shell command, and this child process inherits the parent's signal
handlers. If both the parent and child processes receive SIGTERM,
both will attempt to call proc_exit(). This can end badly. For
example, both processes will try to remove themselves from the
PGPROC shared array.
To fix this problem, this commit adds a check in
StartupProcShutdownHandler() to see whether MyProcPid == getpid().
If they match, this is the parent process, and we can proc_exit()
like before. If they do not match, this is a child process, and we
just emit a message to STDERR (in a signal safe manner) and
_exit(), thereby skipping any problematic exit callbacks.
This commit also adds checks in proc_exit(), ProcKill(), and
AuxiliaryProcKill() that verify they are not being called within
such child processes.
Suggested-by: Andres Freund
Reviewed-by: Thomas Munro, Andres Freund
Discussion: https://postgr.es/m/Y9nGDSgIm83FHcad%40paquier.xyz
Discussion: https://postgr.es/m/20230223231503.GA743455%40nathanxps13
Backpatch-through: 11
Dropping a temp table could entail TOAST table access to clean out
toasted catalog entries, such as large pg_constraint.conbin strings
for complex CHECK constraints. If we did that via ON COMMIT DROP,
we triggered the assertion in init_toast_snapshot(), because
there was no provision for setting up a snapshot for the drop
actions. Fix that.
(I assume here that the adjacent truncation actions for ON COMMIT
DELETE ROWS don't have a similar problem: it doesn't seem like
nontransactional truncations would need to touch any toasted fields.
If that proves wrong, we could refactor a bit to have the same
snapshot acquisition cover that too.)
The test case added here does not fail before v15, because that
assertion was added in 277692220 which was not back-patched.
However, the race condition the assertion warns of surely
exists further back, so back-patch to all supported branches.
Per report from Richard Guo.
Discussion: https://postgr.es/m/CAMbWs4-x26=_QxxgdJyNbiCDzvtr2WV5ZDso_v-CukKEe6cBZw@mail.gmail.com
The old documentation encourages entering single-user mode for no
reason, which is a bad plan in most cases. Instead, discourage users
from doing that, and explain the limited cases in which it may be
desirable.
The old documentation claims that running VACUUM as anyone but the
superuser can't possibly work, which is not really true, because it
might be that some other user has enough permissions to VACUUM all
the tables that matter. Weaken the language just a bit.
The old documentation claims that you can't run any commands
when near XID exhaustion, which is false because you can still
run commands that don't require an XID, like a SELECT without a
locking clause.
The old documentation doesn't clearly explain that it's a good idea
to get rid of prepared transactons, long-running transactions, and
replication slots that are preventing (M)XID horizon advancement.
Spell out the steps to do that.
Also, discourage the use of VACUUM FULL and VACUUM FREEZE in
this type of scenario.
Back-patch to v14. Much of this is good advice on all supported
versions, but before 60f1f09ff4
the chances of VACUUM failing in multi-user mode were much higher.
Alexander Alekseev, John Naylor, Robert Haas, reviewed at various
times by Peter Geoghegan, Hannu Krosing, and Andres Freund.
Discussion: http://postgr.es/m/CA+TgmoYtsUDrzaHcmjFhLzTk1VEv29mO_u-MT+XWHrBJ_4nD8A@mail.gmail.com
Some of our src/bin tools read the control file without any kind of
interlocking against concurrent writes from the server. At least ext4
and ntfs can expose partially modified contents when you do that.
For now, we'll try to tolerate this by retrying up to 10 times if the
checksum doesn't match, until we get two reads in a row with the same
bad checksum. This is not guaranteed to reach the right conclusion, but
it seems very likely to. Thanks to Tom Lane for this suggestion.
Various ideas for interlocking or atomicity were considered too
complicated, unportable or expensive given the lack of field reports,
but remain open for future reconsideration.
Back-patch as far as 12. It doesn't seem like a good idea to put a
heuristic change for a very rare problem into the final release of 11.
Reviewed-by: Anton A. Melnikov <aamelnikov@inbox.ru>
Reviewed-by: David Steele <david@pgmasters.net>
Reviewed-by: Michael Paquier <michael@paquier.xyz>
Discussion: https://postgr.es/m/20221123014224.xisi44byq3cf5psi%40awork3.anarazel.de
Commit dc7d70ea added functions that read the control file, but didn't
acquire ControlFileLock. With unlucky timing, file systems that have
weak interlocking like ext4 and ntfs could expose partially overwritten
contents, and the checksum would fail.
Back-patch to all supported releases.
Reviewed-by: David Steele <david@pgmasters.net>
Reviewed-by: Anton A. Melnikov <aamelnikov@inbox.ru>
Reviewed-by: Michael Paquier <michael@paquier.xyz>
Discussion: https://postgr.es/m/20221123014224.xisi44byq3cf5psi%40awork3.anarazel.de
Under interval_ops, some equal values are distinguishable. One such
pair is '24:00:00' and '1 day'. With that being so, btequalimage()
breaches the documented contract for the "equalimage" btree support
function. This can cause incorrect results from index-only scans.
Users should REINDEX any btree indexes having interval-type columns.
After updating, pg_amcheck will report an error for almost all such
indexes. This fix makes interval_ops simply omit the support function,
like numeric_ops does. Back-pack to v13, where btequalimage() first
appeared. In back branches, for the benefit of old catalog content,
btequalimage() code will return false for type "interval". Going
forward, back-branch initdb will include the catalog change.
Reviewed by Peter Geoghegan.
Discussion: https://postgr.es/m/20231011013317.22.nmisch@google.com
Starting on 2023-08-03, this intermittently terminated a "pgbench -C"
test in CI. It could affect a high-client-count "pgbench" without "-C".
While parallel reindexdb and vacuumdb reach the same problematic check,
sufficient client count and/or connection turnover is less plausible for
them. Given the lack of examples from the buildfarm or from manual
builds, reproducing this must entail rare operating system
configurations. Also correct the associated error message, which was
wrong for non-Windows. Back-patch to v12, where the pgbench check first
appeared. While v11 vacuumdb has the problematic check, reaching it
with typical vacuumdb usage is implausible.
Reviewed by Thomas Munro.
Discussion: https://postgr.es/m/CA+hUKG+JwvTNdcyJTriy9BbtzF1veSRQ=9M_ZKFn9_LqE7Kp7Q@mail.gmail.com
This could only affect HASH partitioned tables with at least 2 partition
key columns.
If partition pruning was delayed until execution and the query contained
an IS NULL qual on one of the partitioned keys, and some subsequent
partitioned key was being compared to a non-Const, then this could result
in a crash due to the incorrect keyno being used to calculate the
stateidx for the expression evaluation code.
Here we fix this by properly skipping partitioned keys which have a
nullkey set. Effectively, this must be the same as what's going on
inside perform_pruning_base_step().
Sergei Glukhov also provided a patch, but that's not what's being used
here.
Reported-by: Sergei Glukhov
Reviewed-by: tender wang, Sergei Glukhov
Discussion: https://postgr.es/m/d05b26fa-af54-27e1-f693-6c31590802fa@postgrespro.ru
Backpatch-through: 11, where runtime partition pruning was added.
get_steps_using_prefix_recurse() incorrectly assumed that it could stop
recursive processing of the 'prefix' list when cur_keyno was one before
the step_lastkeyno. Since hash partition pruning can prune using IS
NULL quals, and these IS NULL quals are not present in the 'prefix'
list, then that logic could cause more levels of recursion than what is
needed and lead to there being no more items in the 'prefix' list to
process. This would manifest itself as a crash in some code that
expected the 'start' ListCell not to be NULL.
Here we adjust the logic so that instead of stopping recursion at 1 key
before the step_lastkeyno, we just look at the llast(prefix) item and
ensure we only recursively process up until just before whichever the last
key is. This effectively allows keys to be missing in the 'prefix' list.
This change does mean that step_lastkeyno is no longer needed, so we
remove that from the static functions. I also spent quite some time
reading this code and testing it to try to convince myself that there
are no other issues. That resulted in the irresistible temptation of
rewriting some comments, many of which were just not true or inconcise.
Reported-by: Sergei Glukhov
Reviewed-by: Sergei Glukhov, tender wang
Discussion: https://postgr.es/m/2f09ce72-315e-2a33-589a-8519ada8df61@postgrespro.ru
Backpatch-through: 11, where partition pruning was introduced.
While these two built-in functions do exactly the same thing,
CURRENT_USER seems preferable to use in documentation examples.
It's easier to look up if the reader is unsure what it is.
Also, this puts these examples in sync with an adjacent example
that already used CURRENT_USER.
Per question from Kirk Parker.
Discussion: https://postgr.es/m/CANwZ8rmN_Eb0h0hoMRS8Feftaik0z89PxVsKg+cP+PctuOq=Qg@mail.gmail.com
Ensure we switch to the per-tuple memory context to prevent any memory
leaks of detoasted Datums in MemoizeHash_hash() and MemoizeHash_equal().
Reported-by: Orlov Aleksej
Author: Orlov Aleksej, David Rowley
Discussion: https://postgr.es/m/83281eed63c74e4f940317186372abfd%40cft.ru
Backpatch-through: 14, where Memoize was added
The code in charge of copying the contents of PgBackendStatus to local
memory could fail on memory allocation because of an overflow on the
amount of memory to use. The overflow can happen when combining a high
value track_activity_query_size (max at 1MB) with a large
max_connections, when both multiplied get higher than INT32_MAX as both
parameters treated as signed integers. This could for example trigger
with the following functions, all calling pgstat_read_current_status():
- pg_stat_get_backend_subxact()
- pg_stat_get_backend_idset()
- pg_stat_get_progress_info()
- pg_stat_get_activity()
- pg_stat_get_db_numbackends()
The change to use MemoryContextAllocHuge() has been introduced in
8d0ddccec6, so backpatch down to 12.
Author: Jakub Wartak
Discussion: https://postgr.es/m/CAKZiRmw8QSNVw2qNK-dznsatQqz+9DkCquxP0GHbbv1jMkGHMA@mail.gmail.com
Backpatch-through: 12
This commit changes the WAL reader routines so as a FATAL for the
backend or exit(FAILURE) for the frontend is triggered if an allocation
for a WAL record decode fails in walreader.c, rather than treating this
case as bogus data, which would be equivalent to the end of WAL. The
key is to avoid palloc_extended(MCXT_ALLOC_NO_OOM) in walreader.c,
relying on plain palloc() calls.
The previous behavior could make WAL replay finish too early than it
should. For example, crash recovery finishing earlier may corrupt
clusters because not all the WAL available locally was replayed to
ensure a consistent state. Out-of-memory failures would show up
randomly depending on the memory pressure on the host, but one simple
case would be to generate a large record, then replay this record after
downsizing a host, as Ethan Mertz originally reported.
This relies on bae868caf2, as the WAL reader routines now do the
memory allocation required for a record only once its header has been
fully read and validated, making xl_tot_len trustable. Making the WAL
reader react differently on out-of-memory or bogus record data would
require ABI changes, so this is the safest choice for stable branches.
Also, it is worth noting that 3f1ce97346 has been using a plain
palloc() in this code for some time now.
Thanks to Noah Misch and Thomas Munro for the discussion.
Like the other commit, backpatch down to 12, leaving out v11 that will
be EOL'd soon. The behavior of considering a failed allocation as bogus
data comes originally from 0ffe11abd3, where the record length
retrieved from its header was not entirely trustable.
Reported-by: Ethan Mertz
Discussion: https://postgr.es/m/ZRKKdI5-RRlta3aF@paquier.xyz
Backpatch-through: 12
In a selective restore, ACLs for a table should be dumped if the
table is selected to be dumped. However, if the table has both
table-level and column-level ACLs, only the table-level ACL was
restored. This happened because _tocEntryRequired assumed that
an ACL could have only one dependency (the one on its table),
and punted if there was more than one. But since commit ea9125304,
column-level ACLs also depend on the table-level ACL if any, to
ensure correct ordering in parallel restores. To fix, adjust the
logic in _tocEntryRequired to ignore dependencies on ACLs.
I extended a test case in 002_pg_dump.pl so that it purports to
test for this; but in fact the test passes even without the fix.
That's because this bug only manifests during a selective restore,
while the scenarios 002_pg_dump.pl tests include only selective dumps.
Perhaps somebody would like to extend the script so that it can test
scenarios including selective restore, but I'm not touching that.
Euler Taveira and Tom Lane, per report from Kong Man.
Back-patch to all supported branches.
Discussion: https://postgr.es/m/DM4PR11MB73976902DBBA10B1D652F9498B06A@DM4PR11MB7397.namprd11.prod.outlook.com
After receiving position data for a lexeme, tsvectorrecv()
advanced its "datalen" value by (npos+1)*sizeof(WordEntry)
where the correct calculation is (npos+1)*sizeof(WordEntryPos).
This accidentally failed to render the constructed tsvector
invalid, but it did result in leaving some wasted space
approximately equal to the space consumed by the position data.
That could have several bad effects:
* Disk space is wasted if the received tsvector is stored into a
table as-is.
* A legal tsvector could get rejected with "maximum total lexeme
length exceeded" if the extra space pushes it over the MAXSTRPOS
limit.
* In edge cases, the finished tsvector could be assigned a length
larger than the allocated size of its palloc chunk, conceivably
leading to SIGSEGV when the tsvector gets copied somewhere else.
The odds of a field failure of this sort seem low, though valgrind
testing could probably have found this.
While we're here, let's express the calculation as
"sizeof(uint16) + npos * sizeof(WordEntryPos)" to avoid the type
pun implicit in the "npos + 1" formulation. It's not wrong
given that WordEntryPos had better be 2 bytes to avoid padding
problems, but it seems clearer this way.
Report and patch by Denis Erokhin. Back-patch to all supported
versions.
Discussion: https://postgr.es/m/009801d9f2d9$f29730c0$d7c59240$@datagile.ru
In recent releases, such cases fail with "cache lookup failed for
function 0" rather than complaining that the conversion function
doesn't exist as prior versions did. Seems to be a consequence of
sloppy refactoring in commit f82de5c46. Add the missing error check.
Per report from Pierre Fortin. Back-patch to v14 where the
oversight crept in.
Discussion: https://postgr.es/m/20230929163739.3bea46e5.pfortin@pfortin.com
ANALYZE on a table with inheritance children analyzes all the child
tables in a loop. When stepping to next child table, it updated the
child rel ID value in the command progress stats, but did not reset
the 'sample_blks_total' and 'sample_blks_scanned' counters.
acquire_sample_rows() updates 'sample_blks_total' as soon as the scan
starts and 'sample_blks_scanned' after processing the first block, but
until then, pg_stat_progress_analyze would display a bogus combination
of the new child table relid with old counter values from the
previously processed child table. Fix by resetting 'sample_blks_total'
and 'sample_blks_scanned' to zero at the same time that
'current_child_table_relid' is updated.
Backpatch to v13, where pg_stat_progress_analyze view was introduced.
Reported-by: Justin Pryzby
Discussion: https://www.postgresql.org/message-id/20230122162345.GP13860%40telsasoft.com
Add "-gmt 1" to our test invocations of the Tcl "clock" command,
so that they do not consult the timezone environment. While it
doesn't really matter which timezone is used here, it does
matter that the command not fall over entirely. We've now
discovered that at least on FreeBSD, "clock scan" will fail if
/etc/localtime is missing. It seems worth making the test
insensitive to that.
Per Tomas Vondras' buildfarm animal dikkop. Thanks to
Thomas Munro for the diagnosis.
Discussion: https://postgr.es/m/316d304a-1dcd-cea1-3d6c-27f794727a06@enterprisedb.com
As of Xcode 15 (macOS Sonoma), the linker complains about duplicate
references to the same library. We see warnings about libpgport and
libpgcommon being duplicated in many client executables. This is a
consequence of the hack introduced in commit 6b7ef076b to list
libpgport before libpq while not removing it from $(LIBS).
(Commit 8396447cd later applied the same rule to libpgcommon.)
The concern in 6b7ef076b was to ensure that the client executable
wouldn't unintentionally depend on pgport functions from libpq.
That concern is obsolete on any platform for which we can do symbol
export control, because if we can then the pgport functions in libpq
won't be exposed anyway. Hence, we can fix this problem by just
removing libpgport and libpgcommon from $(libpq_pgport), and letting
clients depend on the occurrences in $(LIBS).
In the back branches, do that only on macOS (which we know has
symbol export control). In HEAD, let's be more aggressive and
remove the extra libraries everywhere. The only still-supported
platforms that lack export control are MinGW/Cygwin, and it
doesn't seem worth sweating over ABI stability details for those
(or if somebody does care, it'd probably be possible to perform
symbol export control for those too). As well as being simpler,
this might give some microscopic improvement in build time.
The meson build system is not changed here, as it doesn't have
this particular disease, though it does have some related issues
that we'll fix separately.
Discussion: https://postgr.es/m/467042.1695766998@sss.pgh.pa.us
Commit 7d3b7011b added a link to the statistics functions, which at the
time were anchored under the section for statistics views. aebe989477
added a separate section for statistics functions, but the link was not
updated to point to the new anchor. Fix by changing the xref.
Backpatch to all supported branches.
Author: Peter Smith <peter.b.smith@fujitsu.com>
Discussion: https://postgr.es/m/CAHut+Ptr0jKzNNtWnssLq+3jNhbyaBseqf6NPrWHk08mQFRoTg@mail.gmail.com
Backpatch-through: 11
nbtree's mark/restore processing failed to correctly handle an edge case
involving array key advancement and related search-type scan key state.
Scans with ScalarArrayScalarArrayOpExpr quals requiring mark/restore
processing (for a merge join) could incorrectly conclude that an
affected array/scan key must not have advanced during the time between
marking and restoring the scan's position.
As a result of all this, array key handling within btrestrpos could skip
a required call to _bt_preprocess_keys(). This confusion allowed later
primitive index scans to overlook tuples matching the true current array
keys. The scan's search-type scan keys would still have spurious values
corresponding to the final array element(s) -- not values matching the
first/now-current array element(s).
To fix, remember that "array key wraparound" has taken place during the
ongoing btrescan in a flag variable stored in the scan's state, and use
that information at the point where btrestrpos decides if another call
to _bt_preprocess_keys is required.
Oversight in commit 70bc5833, which taught nbtree to handle array keys
during mark/restore processing, but missed this subtlety. That commit
was itself a bug fix for an issue in commit 9e8da0f7, which taught
nbtree to handle ScalarArrayOpExpr quals natively.
Author: Peter Geoghegan <pg@bowt.ie>
Discussion: https://postgr.es/m/CAH2-WzkgP3DDRJxw6DgjCxo-cu-DKrvjEv_ArkP2ctBJatDCYg@mail.gmail.com
Backpatch: 11- (all supported branches).
This code was sloppy about comparison of index columns that
are expressions. It didn't reliably reject cases where one
index has an expression where the other has a plain column,
and it could index off the start of the attmap array, leading
to a Valgrind complaint (though an actual crash seems unlikely).
I'm not sure that the expression-vs-column sloppiness leads
to any visible problem in practice, because the subsequent
comparison of the two expression lists would reject cases
where the indexes have different numbers of expressions
overall. Maybe we could falsely match indexes having the
same expressions in different column positions, but it'd
require unlucky contents of the word before the attmap array.
It's not too surprising that no problem has been reported
from the field. Nonetheless, this code is clearly wrong.
Per bug #18135 from Alexander Lakhin. Back-patch to all
supported branches.
Discussion: https://postgr.es/m/18135-532f4a755e71e4d2@postgresql.org
Tid Range scans were added back in bb437f995. That commit forgot to add
handling for TidRangePaths in print_path().
Only people building with OPTIMIZER_DEBUG might have noticed this, which
likely is the reason it's taken 4 years for anyone to notice.
Author: Andrey Lepikhov
Reported-by: Andrey Lepikhov
Discussion: https://postgr.es/m/379082d6-1b6a-4cd6-9ecf-7157d8c08635@postgrespro.ru
Backpatch-through: 14, where bb437f995 was introduced
As coded, the module's Makefile would fail to set a value for PYTHON as
it checked if the variable is defined. When compiling without
--with-python, PYTHON is defined and set to an empty value, so the
existing check is not able to do its work.
This commit switches the rule to check if the value is empty rather than
defined, allowing the generation of unaccent.rules even if --with-python
is not used as long as "python" exists. BISON and FLEX do the same in
pgxs.mk, for instance.
Thinko in f85a485f89.
Author: Japin Li
Discussion: https://postgr.es/m/MEYP282MB1669F86C0DC7B4DC48489CB0B6C3A@MEYP282MB1669.AUSP282.PROD.OUTLOOK.COM
Backpatch-through: 13
We started to use this linker switch in commit 9df308697 of
2004-07-13, which was in the OS X 10.3 era. Apparently it's been a
no-op since around OS X 10.9. Apple's most recent toolchain version
actively complains about it, so it's time to get rid of it.
Discussion: https://postgr.es/m/467042.1695766998@sss.pgh.pa.us
Yet another bug in the ilk of commits a7ee7c851 and 741b88435. In
741b88435, we took care to clear the memorized location of the
downlink when we split the parent page, because splitting the parent
page can move the downlink. But we missed that even *updating* a tuple
on the parent can move it, because updating a tuple on a gist page is
implemented as a delete+insert, so the updated tuple gets moved to the
end of the page.
This commit fixes the bug in two different ways (belt and suspenders):
1. Clear the downlink when we update a tuple on the parent page, even
if it's not split. This the same approach as in commits a7ee7c851
and 741b88435.
I also noticed that gistFindCorrectParent did not clear the
'downlinkoffnum' when it stepped to the right sibling. Fix that
too, as it seems like a clear bug even though I haven't been able
to find a test case to hit that.
2. Change gistFindCorrectParent so that it treats 'downlinkoffnum'
merely as a hint. It now always first checks if the downlink is
still at that location, and if not, it scans the page like before.
That's more robust if there are still more cases where we fail to
clear 'downlinkoffnum' that we haven't yet uncovered. With this,
it's no longer necessary to meticulously clear 'downlinkoffnum',
so this makes the previous fixes unnecessary, but I didn't revert
them because it still seems nice to clear it when we know that the
downlink has moved.
Also add the test case using the same test data that Alexander
posted. I tried to reduce it to a smaller test, and I also tried to
reproduce this with different test data, but I was not able to, so
let's just include what we have.
Backpatch to v12, like the previous fixes.
Reported-by: Alexander Lakhin
Discussion: https://www.postgresql.org/message-id/18129-caca016eaf0c3702@postgresql.org
bae868ca removed a check that was still needed. If you had an
xl_tot_len at the end of a page that was too small for a record header,
but not big enough to span onto the next page, we'd immediately perform
the CRC check using a bogus large length. Because of arbitrary coding
differences between the CRC implementations on different platforms,
nothing very bad happened on common modern systems. On systems using
the _sb8.c fallback we could segfault.
Restore that check, add a new assertion and supply a test for that case.
Back-patch to 12, like bae868ca.
Tested-by: Tom Lane <tgl@sss.pgh.pa.us>
Tested-by: Alexander Lakhin <exclusion@gmail.com>
Discussion: https://postgr.es/m/CA%2BhUKGLCkTT7zYjzOxuLGahBdQ%3DMcF%3Dz5ZvrjSOnW4EDhVjT-g%40mail.gmail.com
For some reason I used not_like = { pg_dumpall_dbprivs => 1, } in the test
condition of one of the tests added in in c66a7d75e6. That doesn't make sense
for two reasons: 1) not_like isn't a valid test condition 2) the database
should not be dumped in any of the tests. Due to 1), the test achieved its
goal, but clearly the formulation is confusing. Instead use like => {}, with
a comment explaining why.
Reported-by: Peter Eisentraut <peter@eisentraut.org>
Discussion: https://postgr.es/m/3ddf79f2-8b7b-a093-11d2-5c739bc64f86@eisentraut.org
Backpatch: 11-, like c66a7d75e6
Parse analysis of a CallStmt will inject mutable information,
for instance the OID of the called procedure, so that subsequent
DDL may create a need to re-parse the CALL. We failed to detect
this for CALLs in plpgsql routines, because no dependency information
was collected when putting a CallStmt into the plan cache. That
could lead to misbehavior or strange errors such as "cache lookup
failed".
Before commit ee895a655, the issue would only manifest for CALLs
appearing in atomic contexts, because we re-planned non-atomic
CALLs every time through anyway.
It is now apparent that extract_query_dependencies() probably
needs a special case for every utility statement type for which
stmt_requires_parse_analysis() returns true. I wanted to add
something like Assert(!stmt_requires_parse_analysis(...)) when
falling out of extract_query_dependencies_walker without doing
anything, but there are API issues as well as a more fundamental
point: stmt_requires_parse_analysis is supposed to be applied to
raw parser output, so it'd be cheating to assume it will give the
correct answer for post-parse-analysis trees. I contented myself
with adding a comment.
Per bug #18131 from Christian Stork. Back-patch to all supported
branches.
Discussion: https://postgr.es/m/18131-576854e79c5cd264@postgresql.org
The initial estimate of the number of distinct ParsedWords is just
that: an estimate. Don't let it exceed what palloc is willing to
allocate. If in fact we need more entries, we'll eventually fail
trying to enlarge the array. But if we don't, this allows success on
inputs that currently draw "invalid memory alloc request size".
Per bug #18080 from Uwe Binder. Back-patch to all supported branches.
Discussion: https://postgr.es/m/18080-d5c5e58fef8c99b7@postgresql.org
Commit cda6a8d01d removed a few datatypes, but didn't update
pg_upgrade --check to throw error if these types are used. So the users
find that pg_upgrade --check tells them that everything is fine, only to
fail when the real upgrade is attempted.
Reviewed-by: Tristan Partin <tristan@neon.tech>
Reviewed-by: Suraj Kharage <suraj.kharage@enterprisedb.com>
Discussion: https://postgr.es/m/202309201654.ng4ksea25mti@alvherre.pgsql
'Q' for 64 bit integers turns out not to work on 32 bit Perl, as
revealed by the build farm. Use 'II' instead, and deal with endianness.
Back-patch to 12, like bae868ca.
Discussion: https://postgr.es/m/ZQ4r1vHcryBsSi_V%40paquier.xyz
xl_tot_len comes first in a WAL record. Usually we don't trust it to be
the true length until we've validated the record header. If the record
header was split across two pages, previously we wouldn't do the
validation until after we'd already tried to allocate enough memory to
hold the record, which was bad because it might actually be garbage
bytes from a recycled WAL file, so we could try to allocate a lot of
memory. Release 15 made it worse.
Since 70b4f82a4b, we'd at least generate an end-of-WAL condition if the
garbage 4 byte value happened to be > 1GB, but we'd still try to
allocate up to 1GB of memory bogusly otherwise. That was an
improvement, but unfortunately release 15 tries to allocate another
object before that, so you could get a FATAL error and recovery could
fail.
We can fix both variants of the problem more fundamentally using
pre-existing page-level validation, if we just re-order some logic.
The new order of operations in the split-header case defers all memory
allocation based on xl_tot_len until we've read the following page. At
that point we know that its first few bytes are not recycled data, by
checking its xlp_pageaddr, and that its xlp_rem_len agrees with
xl_tot_len on the preceding page. That is strong evidence that
xl_tot_len was truly the start of a record that was logged.
This problem was most likely to occur on a standby, because
walreceiver.c recycles WAL files without zeroing out trailing regions of
each page. We could fix that too, but it wouldn't protect us from rare
crash scenarios where the trailing zeroes don't make it to disk.
With reliable xl_tot_len validation in place, the ancient policy of
considering malloc failure to indicate corruption at end-of-WAL seems
quite surprising, but changing that is left for later work.
Also included is a new TAP test to exercise various cases of end-of-WAL
detection by writing contrived data into the WAL from Perl.
Back-patch to 12. We decided not to put this change into the final
release of 11.
Author: Thomas Munro <thomas.munro@gmail.com>
Author: Michael Paquier <michael@paquier.xyz>
Reported-by: Alexander Lakhin <exclusion@gmail.com>
Reviewed-by: Noah Misch <noah@leadboat.com> (the idea, not the code)
Reviewed-by: Michael Paquier <michael@paquier.xyz>
Reviewed-by: Sergei Kornilov <sk@zsrv.org>
Reviewed-by: Alexander Lakhin <exclusion@gmail.com>
Discussion: https://postgr.es/m/17928-aa92416a70ff44a2%40postgresql.org
The previous wording had a faint archaic whiff to it, and more
importantly used "catalogs" as a verb, which while cutely
self-referential seems likely to provoke confusion in this
particular context. Also consistently use "kind" not "type" to
refer to the different kinds of relations distinguished by relkind.
Per gripe from Martin Nash. Back-patch to supported versions.
Discussion: https://postgr.es/m/169518739902.3727338.4793815593763320945@wrigleys.postgresql.org
Nathan Bossart