This has previously not been a problem (that anyone ever reported),
but in future OpenSSL versions (3.0.0), where legacy ciphers are/can
be disabled, this is the place where this is reported. So we need to
catch the error here, otherwise the higher-level functions would
return garbage. The nearby encryption code already handled errors
similarly.
Author: Peter Eisentraut <peter@eisentraut.org>
Reviewed-by: Daniel Gustafsson <daniel@yesql.se>
Discussion: https://www.postgresql.org/message-id/9e9c431c-0adc-7a6d-9b1a-915de1ba3fe7@enterprisedb.com
Backpatch-through: 9.6
Index vacuums may happen multiple times depending on the number of dead
tuples stored, as of maintenance_work_mem for a manual VACUUM. For
autovacuum, this is controlled by autovacuum_work_mem instead, if set.
The documentation mentioned the former, but not the latter in the
context of autovacuum.
Reported-by: Nikolai Berkoff
Author: Laurenz Albe, Euler Taveira
Discussion: https://postgr.es/m/161545365522.10134.12195402324485546870@wrigleys.postgresql.org
Backpatch-through: 9.6
Calculating degree of a functional dependency may allocate a lot of
memory - we have released mot of the explicitly allocated memory, but
e.g. detoasted varlena values were left behind. That may be an issue,
because we consider a lot of dependencies (all combinations), and the
detoasting may happen for each one again.
Fixed by calling dependency_degree() in a dedicated context, and
resetting it after each call. We only need the calculated dependency
degree, so we don't need to copy anything.
Backpatch to PostgreSQL 10, where extended statistics were introduced.
Backpatch-through: 10
Discussion: https://www.postgresql.org/message-id/20210915200928.GP831%40telsasoft.com
Until now, all extended statistics on a given relation were built in the
same memory context, without resetting. Some of the memory was released
explicitly, but not all of it - for example memory allocated while
detoasting values is hard to free. This is how it worked since extended
statistics were introduced in PostgreSQL 10, but adding support for
extended stats on expressions made the issue somewhat worse as it
increases the number of statistics to build.
Fixed by adding a memory context which gets reset after building each
statistics object (all the statistics kinds included in it). Resetting
it after building each statistics kind would be even better, but it
would require more invasive changes and copying of results, making it
harder to backpatch.
Backpatch to PostgreSQL 10, where extended statistics were introduced.
Author: Justin Pryzby
Reported-by: Justin Pryzby
Reviewed-by: Tomas Vondra
Backpatch-through: 10
Discussion: https://www.postgresql.org/message-id/20210915200928.GP831%40telsasoft.com
Contrary to the output of native perl, Msys perl generates outputs with
CRLFs characters. There are already places in the TAP code where CRLFs
(\r\n) are automatically converted to LF (\n) on Msys, but we missed a
couple of places when running commands and using their output for
comparison, that would lead to failures.
This problem has been found thanks to the test added in 5adb067 using
TestLib::command_checks_all(), but after a closer look more code paths
were missing a filter.
This is backpatched all the way down to prevent any surprises if a new
test is introduced in stable branches.
Reviewed-by: Andrew Dunstan, Álvaro Herrera
Discussion: https://postgr.es/m/1252480.1631829409@sss.pgh.pa.us
Backpatch-through: 9.6
Before commit 84f5c2908, a STABLE function in a plpgsql CALL
statement's argument list would see an up-to-date snapshot,
because exec_stmt_call would push a new snapshot. I got rid of
that because the possibility of the snapshot disappearing within
COMMIT made it too hard to manage a snapshot across the CALL
statement. That's fine so far as the procedure itself goes,
but I forgot to think about the possibility of STABLE functions
within the CALL argument list. As things now stand, those'll
be executed with the Portal's snapshot as ActiveSnapshot,
keeping them from seeing updates more recent than Portal startup.
(VOLATILE functions don't have a problem because they take their
own snapshots; which indeed is also why the procedure itself
doesn't have a problem. There are no STABLE procedures.)
We can fix this by pushing a new snapshot transiently within
ExecuteCallStmt itself. Popping the snapshot before we get
into the procedure proper eliminates the management problem.
The possibly-useless extra snapshot-grab is slightly annoying,
but it's no worse than what happened before 84f5c2908.
Per bug #17199 from Alexander Nawratil. Back-patch to v11,
like the previous patch.
Discussion: https://postgr.es/m/17199-1ab2561f0d94af92@postgresql.org
A broken HOT chain is not an unexpected condition, even when the offset
number points past the end of the page's line pointer array.
heap_prune_chain() does not (and never has) treated this condition as
unexpected, so derivative code in heap_index_delete_tuples() shouldn't
do so either.
Oversight in commit 4228817449.
The assertion can probably only fail on Postgres 14 and master. Earlier
releases don't have commit 3c3b8a4b, which taught VACUUM to truncate the
line pointer array of heap pages. Backpatch all the same, just to be
consistent.
Author: Peter Geoghegan <pg@bowt.ie>
Reported-By: Alexander Lakhin <exclusion@gmail.com>
Discussion: https://postgr.es/m/17197-9438f31f46705182@postgresql.org
Backpatch: 12-, just like commit 4228817449.
Casting a value that's already of a type with a specific typmod
to an unspecified typmod doesn't do anything so far as run-time
behavior is concerned. However, it really ought to change the
exposed type of the expression to match. Up to now,
coerce_type_typmod hasn't bothered with that, which creates gotchas
in contexts such as recursive unions. If for example one side of
the union is numeric(18,3), but it needs to be plain numeric to
match the other side, there's no direct way to express that.
This is easy enough to fix, by inserting a RelabelType to update the
exposed type of the expression. However, it's a bit nervous-making
to change this behavior, because it's stood for a really long time.
But no complaints have emerged about 14beta3, so go ahead and
back-patch.
Back-patch of 5c056b0c2 into previous supported branches.
Discussion: https://postgr.es/m/CABNQVagu3bZGqiTjb31a8D5Od3fUMs7Oh3gmZMQZVHZ=uWWWfQ@mail.gmail.com
Discussion: https://postgr.es/m/1488389.1631984807@sss.pgh.pa.us
Commit 55dc86eca changed pull_varnos to use (if possible) the associated
ph_eval_at for a PlaceHolderVar. I missed a fine point though: we might
be looking at a PHV in the quals or tlist of a child appendrel, in which
case we need to compute a ph_eval_at value that's been translated in the
same way that the PHV itself has been (cf. adjust_appendrel_attrs).
Fortunately, enough info is available in the PlaceHolderInfo to make
such translation possible without additional outside data, so we don't
need another round of uglification of planner APIs. This is a little
bit complicated, but since it's a hard-to-hit corner case, I'm not much
worried about adding cycles here.
Per report from Jaime Casanova. Back-patch to v12, like the previous
commit.
Discussion: https://postgr.es/m/20210915230959.GB17635@ahch-to
ProcArrayGroupClearXid function has a parameter named "proc",
but the same name was used for its local variables. This commit fixes
this variable shadowing, to improve code readability.
Back-patch to all supported versions, to make future back-patching
easy though this patch is classified as refactoring only.
Reported-by: Ranier Vilela
Author: Ranier Vilela, Aleksander Alekseev
https://postgr.es/m/CAEudQAqyoTZC670xWi6w-Oe2_Bk1bfu2JzXz6xRfiOUzm7xbyQ@mail.gmail.com
If an allocation failed within LLVM it is not safe to call back into LLVM as
LLVM is not generally safe against exceptions / stack-unwinding. Thus errors
while in LLVM code are promoted to FATAL. However llvm_shutdown() did call
back into LLVM even in such cases, while llvm_release_context() was careful
not to do so.
We cannot generally skip shutting down LLVM, as that can break profiling. But
it's OK to do so if there was an error from within LLVM.
Reported-By: Jelte Fennema <Jelte.Fennema@microsoft.com>
Author: Andres Freund <andres@anarazel.de>
Author: Justin Pryzby <pryzby@telsasoft.com>
Discussion: https://postgr.es/m/AM5PR83MB0178C52CCA0A8DEA0207DC14F7FF9@AM5PR83MB0178.EURPRD83.prod.outlook.com
Backpatch: 11-, where jit was introduced
Ordinarily, using EXIT this way would draw "control reached end of
function without RETURN". However, if the function is one where we
don't require an explicit RETURN (such as a DO block), that should
not happen. It did anyway, because add_dummy_return() neglected to
account for the case.
Per report from Herwig Goemans. Back-patch to all supported branches.
Discussion: https://postgr.es/m/868ae948-e3ca-c7ec-95a6-83cfc08ef750@gmail.com
An out-of-memory failure happening when allocating the structures to
store the connection parameter keywords and values would mess up with
the set of connections saved, as on failure the pthread mutex would
still be hold with the new connection object listed but free()'d.
Rather than just unlocking the mutex, which would leave the static list
of connections into an inconsistent state, move the allocation for the
structures of the connection parameters before beginning the test
manipulation. This ensures that the list of connections and the
connection mutex remain consistent all the time in this code path.
This error is unlikely going to happen, but this could mess up badly
with ECPG clients in surprising ways, so backpatch all the way down.
Reported-by: ryancaicse
Discussion: https://postgr.es/m/17186-b4cfd8f0eb4d1dee@postgresql.org
Backpatch-through: 9.6
If search_start is greater than the length of the string, we should just
return REG_NOMATCH immediately. (Note that the equality case should
*not* be rejected, since the pattern might be able to match zero
characters.) This guards various internal assumptions that the min of a
range of string positions is not more than the max. Violation of those
assumptions could allow an attempt to fetch string[search_start-1],
possibly causing a crash.
Jaime Casanova pointed out that this situation is reachable with the
new regexp_xxx functions that accept a user-specified start position.
I don't believe it's reachable via any in-core call site in v14 and
below. However, extensions could possibly call pg_regexec with an
out-of-range search_start, so let's back-patch the fix anyway.
Discussion: https://postgr.es/m/20210911180357.GA6870@ahch-to
We have long forbidden fetching backwards from a NO SCROLL cursor,
but the prohibition didn't extend to cases in which we rewind the
query altogether and then re-fetch forwards. I think the reason is
that this logic was mainly meant to protect plan nodes that can't
be run in the reverse direction. However, re-reading the query output
is problematic if the query is volatile (which includes SELECT FOR
UPDATE, not just queries with volatile functions): the re-read can
produce different results, which confuses the cursor navigation logic
completely. Another reason for disliking this approach is that some
code paths will either fetch backwards or rewind-and-fetch-forwards
depending on the distance to the target row; so that seemingly
identical use-cases may or may not draw the "cursor can only scan
forward" error. Hence, let's clean things up by disallowing rewind
as well as fetch-backwards in a NO SCROLL cursor.
Ordinarily we'd only make such a definitional change in HEAD, but
there is a third reason to consider this change now. Commit ba2c6d6ce
created some new user-visible anomalies for non-scrollable cursors
WITH HOLD, in that navigation in the cursor result got confused if the
cursor had been partially read before committing. The only good way
to resolve those anomalies is to forbid rewinding such a cursor, which
allows removal of the incorrect cursor state manipulations that
ba2c6d6ce added to PersistHoldablePortal.
To minimize the behavioral change in the back branches (including
v14), refuse to rewind a NO SCROLL cursor only when it has a holdStore,
ie has been held over from a previous transaction due to WITH HOLD.
This should avoid breaking most applications that have been sloppy
about whether to declare cursors as scrollable. We'll enforce the
prohibition across-the-board beginning in v15.
Back-patch to v11, as ba2c6d6ce was.
Discussion: https://postgr.es/m/3712911.1631207435@sss.pgh.pa.us
Some plan node types don't react well to being called again after
they've already returned NULL. PortalRunSelect() has long dealt
with this by calling the executor with NoMovementScanDirection
if it sees that we've already run the portal to the end. However,
commit ba2c6d6ce overlooked this point, so that persisting an
already-fully-fetched cursor would fail if it had such a plan.
Per report from Tomas Barton. Back-patch to v11, as the faulty
commit was. (I've omitted a test case because the type of plan
that causes a problem isn't all that stable.)
Discussion: https://postgr.es/m/CAPV2KRjd=ErgVGbvO2Ty20tKTEZZr6cYsYLxgN_W3eAo9pf5sw@mail.gmail.com
We don't allow relations to exceed 2^32-1 blocks, because block
numbers are 32 bits and the last possible block number is reserved
to mean InvalidBlockNumber. There is a check for this in mdextend,
but that's really way too late, because the smgr API requires us to
create a buffer for the block-to-be-added, and we do not want to
have any buffer with blocknum InvalidBlockNumber. (Such a case
can trigger assertions in bufmgr.c, plus I think it might confuse
ReadBuffer's logic for data-past-EOF later on.) So put the check
into ReadBuffer.
Per report from Christoph Berg. It's been like this forever,
so back-patch to all supported branches.
Discussion: https://postgr.es/m/YTn1iTkUYBZfcODk@msg.credativ.de
Previously, walreceiver always closed the currently-opened WAL segment
and created its archive notification file, after it finished writing
the current segment up and received any WAL data that should be
written into the next segment. If walreceiver exited just before
any WAL data in the next segment arrived at standby, it did not
create the archive notification file of the current segment
even though that's known completed. This behavior could cause
WAL archiving of the segment to be delayed until subsequent
restartpoints or checkpoints created its notification file.
To fix the issue, this commit changes walreceiver so that it creates
an archive notification file of a current WAL segment immediately
if that's known completed before receiving next WAL data.
Back-patch to all supported branches.
Reported-by: Kyotaro Horiguchi
Author: Fujii Masao
Reviewed-by: Kyotaro Horiguchi
Discussion: https://postgr.es/m/20200630.165503.1465894182551545886.horikyota.ntt@gmail.com
Coverity complained that one caller of getFormattedTypeName() failed
to free the returned string. Which is true, but rather than fixing
that one, let's get rid of this tedious and error-prone requirement.
Now that getFormattedTypeName() caches its result, strdup'ing that
result and expecting the caller to free it accomplishes little except
to waste cycles. We do create a leak in the case where getTypes didn't
make a TypeInfo for the type, but that basically shouldn't ever happen.
Back-patch, as commit 6c450a861 was. This isn't a particularly
interesting bug fix, but the API change seems like a hazard for
future back-patching activity if we don't back-patch it.
If we copy data-modifying CTEs from the original query to a replacement
query (from a DO INSTEAD rule), we must set hasModifyingCTE properly
in the replacement query. Failure to do this can cause various
unpleasantness, such as unsafe usage of parallel plans. The code also
neglected to propagate hasRecursive, though that's only cosmetic at
the moment.
A difficulty arises if the rule action is an INSERT...SELECT. We
attach the original query's RTEs and CTEs to the sub-SELECT Query, but
data-modifying CTEs are only allowed to appear in the topmost Query.
For the moment, throw an error in such cases. It would probably be
possible to avoid this error by attaching the CTEs to the top INSERT
Query instead; but that would require a bunch of new code to adjust
ctelevelsup references. Given the narrowness of the use-case, and
the need to back-patch this fix, it does not seem worth the trouble
for now. We can revisit this if we get field complaints.
Per report from Greg Nancarrow. Back-patch to all supported branches.
(The test case added here does not fail before v10, but there are
plenty of places checking top-level hasModifyingCTE in 9.6, so I have
no doubt that this code change is necessary there too.)
Greg Nancarrow and Tom Lane
Discussion: https://postgr.es/m/CAJcOf-f68DT=26YAMz_i0+Au3TcLO5oiHY5=fL6Sfuits6r+_w@mail.gmail.com
Discussion: https://postgr.es/m/CAJcOf-fAdj=nDKMsRhQzndm-O13NY4dL6xGcEvdX5Xvbbi0V7g@mail.gmail.com
Updates/Deletes on a relation were allowed even without replica identity
after we define the publication for all tables. This would later lead to
an error on subscribers. The reason was that for such publications we were
not invalidating the relcache and the publication information for
relations was not getting rebuilt. Similarly, we were not invalidating the
relcache after dropping of such publications which will prohibit
Updates/Deletes without replica identity even without any publication.
Author: Vignesh C and Hou Zhijie
Reviewed-by: Hou Zhijie, Kyotaro Horiguchi, Amit Kapila
Backpatch-through: 10, where it was introduced
Discussion: https://postgr.es/m/CALDaNm0pF6zeWqCA8TCe2sDuwFAy8fCqba=nHampCKag-qLixg@mail.gmail.com
timetz_zone() delivered completely wrong answers if the zone was
specified by a dynamic TZ abbreviation, because it failed to account
for the difference between the POSIX conventions for field values in
struct pg_tm and the conventions used in PG-specific datetime code.
As a stopgap fix, just adjust the tm_year and tm_mon fields to match
PG conventions. This is fixed in a different way in HEAD (388e71af8)
but I don't want to back-patch the change of reference point.
Discussion: https://postgr.es/m/CAJ7c6TOMG8zSNEZtCn5SPe+cCk3Lfxb71ZaQwT2F4T7PJ_t=KA@mail.gmail.com
Attempting to make hashfloat4() look as much as possible like
hashfloat8(), I'd figured I could replace NaNs with get_float4_nan()
before widening to float8. However, results from protosciurus
and topminnow show that on some platforms that produces a different
bit-pattern from get_float8_nan(), breaking the intent of ce773f230.
Rearrange so that we use the result of get_float8_nan() for all NaN
cases. As before, back-patch.
Replace fixed-length command buffers with psprintf() calls. We didn't
have anything as convenient as psprintf() when this code was written,
but now that we do, there's little reason for the limitation to
stand. Removing it eliminates some corner cases where (for example)
starting the postmaster with a whole lot of options fails.
Most individual file names that pg_ctl deals with are still restricted
to MAXPGPATH, but we've seldom had complaints about that limitation
so long as it only applies to one filename.
Back-patch to all supported branches.
Phil Krylov
Discussion: https://postgr.es/m/567e199c6b97ee19deee600311515b86@krylov.eu
Previously this was allowed, but the collation effectively vanished
into the ether because of the way lookup_collation() works: you could
not use the collation, nor even drop it. Seems better to give an
error up front than to leave the user wondering why it doesn't work.
(Because this test is in DefineCollation not CreateCollation, it does
not prevent pg_import_system_collations from creating ICU collations,
regardless of the initially-chosen encoding.)
Per bug #17170 from Andrew Bille. Back-patch to v10 where ICU support
was added.
Discussion: https://postgr.es/m/17170-95845cf3f0a9c36d@postgresql.org
Modern POSIX seems to require strtod() to accept "-NaN", but there's
nothing about NaN in SUSv2, and some of our oldest buildfarm members
don't like it. Let's try writing it as -'NaN' instead; that seems
to produce the same result, at least on Intel hardware.
Per buildfarm.
The IEEE 754 standard allows a wide variety of bit patterns for NaNs,
of which at least two ("NaN" and "-NaN") are pretty easy to produce
from SQL on most machines. This is problematic because our btree
comparison functions deem all NaNs to be equal, but our float hash
functions know nothing about NaNs and will happily produce varying
hash codes for them. That causes unexpected results from queries
that hash a column containing different NaN values. It could also
produce unexpected lookup failures when using a hash index on a
float column, i.e. "WHERE x = 'NaN'" will not find all the rows
it should.
To fix, special-case NaN in the float hash functions, not too much
unlike the existing special case that forces zero and minus zero
to hash the same. I arranged for the most vanilla sort of NaN
(that coming from the C99 NAN constant) to still have the same
hash code as before, to reduce the risk to existing hash indexes.
I dithered about whether to back-patch this into stable branches,
but ultimately decided to do so. It's a clear improvement for
queries that hash internally. If there is anybody who has -NaN
in a hash index, they'd be well advised to re-index after applying
this patch ... but the misbehavior if they don't will not be much
worse than the misbehavior they had before.
Per bug #17172 from Ma Liangzhu.
Discussion: https://postgr.es/m/17172-7505bea9e04e230f@postgresql.org
The check to test whether the subscription workers were restarting after a
change in the subscription was failing. The reason was that the test was
assuming the walsender started before it reaches the 'streaming' state and
the walsender was exiting due to an error before that. Now, the walsender
was erroring out before reaching the 'streaming' state because it tries to
acquire the slot before the previous walsender has exited.
In passing, improve the die messages so that it is easier to investigate
the failures in the future if any.
Reported-by: Michael Paquier, as per buildfarm
Author: Ajin Cherian
Reviewed-by: Masahiko Sawada, Amit Kapila
Backpatch-through: 10, where this test was introduced
Discussion: https://postgr.es/m/YRnhFxa9bo73wfpV@paquier.xyz
For no particularly good reason, getPolicies() queried pg_policy
separately for each table. We can collect all the policies in
a single query instead, and attach them to the correct TableInfo
objects using findTableByOid() lookups. On the regression
database, this reduces the number of queries substantially, and
provides a visible savings even when running against a local
server.
Per complaint from Hubert Depesz Lubaczewski. Since this is such
a simple fix and can have a visible performance benefit, back-patch
to all supported branches.
Discussion: https://postgr.es/m/20210826084430.GA26282@depesz.com
There's long been a "TODO: there might be some value in caching
the results" annotation on pg_dump's getFormattedTypeName function;
but we hadn't gotten around to checking what it was costing us to
repetitively look up type names. It turns out that when dumping the
current regression database, about 10% of the total number of queries
issued are duplicative format_type() queries. However, Hubert Depesz
Lubaczewski reported a not-unusual case where these account for over
half of the queries issued by pg_dump. Individually these queries
aren't expensive, but when network lag is a factor, they add up to a
problem. We can very easily add some caching to getFormattedTypeName
to solve it.
Since this is such a simple fix and can have a visible performance
benefit, back-patch to all supported branches.
Discussion: https://postgr.es/m/20210826084430.GA26282@depesz.com
Commit 5be8ce82e8 added a new role to the stats_ext regression suite,
but the role name did not start with regress_ causing failures when
running with ENFORCE_REGRESSION_TEST_NAME_RESTRICTIONS. Fixed by
renaming the role to start with the expected regress_ prefix.
Backpatch-through: 10, same as the new regression test
Discussion: https://postgr.es/m/1F238937-7CC2-4703-A1B1-6DC225B8978A%40enterprisedb.com
When an ownership check on extended statistics object failed, the code
was calling aclcheck_error_type to report the failure, which is clearly
wrong, resulting in cache lookup errors. Fix by calling aclcheck_error.
This issue exists since the introduction of extended statistics, so
backpatch all the way back to PostgreSQL 10. It went unnoticed because
there were no tests triggering the error, so add one.
Reported-by: Mark Dilger
Backpatch-through: 10, where extended stats were introduced
Discussion: https://postgr.es/m/1F238937-7CC2-4703-A1B1-6DC225B8978A%40enterprisedb.com
Most data-corruption reports mention the location of the problem, but
this one failed to. Add it.
Backpatch all the way back. In 12 and older, also assign the
ERRCODE_DATA_CORRUPTED error code as was done in commit fd6ec93bf8 for
13 and later.
Discussion: https://postgr.es/m/202108191637.oqyzrdtnheir@alvherre.pgsql
Strictly speaking this isn't a bug, but since all references to catalog
objects are schema-qualified, we might as well be consistent. The
omission first appeared in commit 1c5d9270e3, so backpatch to 12.
Author: Justin Pryzby <pryzbyj@telsasoft.com>
Discussion: https://postgr.es/m/20210827193151.GN26465@telsasoft.com
If the system crashed between CREATE TABLESPACE and the next checkpoint,
the result could be some files in the tablespace unexpectedly containing
no rows. Affected files would be those for which the system did not
write WAL; see the wal_skip_threshold documentation. Before v13, a
different set of conditions governed the writing of WAL; see v12's
<sect2 id="populate-pitr">. (The v12 conditions were broader in some
ways and narrower in others.) Users may want to audit non-default
tablespaces for unexpected short files. The bug could have truncated an
index without affecting the associated table, and reindexing the index
would fix that particular problem.
This fixes the bug by making create_tablespace_directories() more like
TablespaceCreateDbspace(). create_tablespace_directories() was
recursively removing tablespace contents, reasoning that WAL redo would
recreate everything removed that way. That assumption holds for other
wal_level values. Under wal_level=minimal, the old approach could
delete files for which no other copy existed. Back-patch to 9.6 (all
supported versions).
Reviewed by Robert Haas and Prabhat Sahu. Reported by Robert Haas.
Discussion: https://postgr.es/m/CA+TgmoaLO9ncuwvr2nN-J4VEP5XyAcy=zKiHxQzBbFRxxGxm0w@mail.gmail.com
Somehow, spgist overlooked the need to call pgstat_count_index_scan().
Hence, pg_stat_all_indexes.idx_scan and equivalent columns never
became nonzero for an SP-GiST index, although the related per-tuple
counters worked fine.
This fix works a bit differently from other index AMs, in that the
counter increment occurs in spgrescan not spggettuple/spggetbitmap.
It looks like this won't make the user-visible semantics noticeably
different, so I won't go to the trouble of introducing an is-this-
the-first-call flag just to make the counter bumps happen in the
same places.
Per bug #17163 from Christian Quest. Back-patch to all supported
versions.
Discussion: https://postgr.es/m/17163-b8c5cc88322a5e92@postgresql.org
Pengchengliu reported an assertion failure in a parallel woker while
performing a parallel scan using an overflowed snapshot. The proximate
cause is that TransactionXmin was set to an incorrect value. The
underlying cause is incorrect snapshot handling in parallel.c.
In particular, InitializeParallelDSM() was unconditionally calling
GetTransactionSnapshot(), because I (rhaas) mistakenly thought that
was always retrieving an existing snapshot whereas, at isolation
levels less than REPEATABLE READ, it's actually taking a new one. So
instead do this only at higher isolation levels where there actually
is a single snapshot for the whole transaction.
By itself, this is not a sufficient fix, because we still need to
guarantee that TransactionXmin gets set properly in the workers. The
easiest way to do that seems to be to install the leader's active
snapshot as the transaction snapshot if the leader did not serialize a
transaction snapshot. This doesn't affect the results of future
GetTrasnactionSnapshot() calls since those have to take a new snapshot
anyway; what we care about is the side effect of setting TransactionXmin.
Report by Pengchengliu. Patch by Greg Nancarrow, except for some comment
text which I supplied.
Discussion: https://postgr.es/m/002f01d748ac$eaa781a0$bff684e0$@tju.edu.cn
Commit 325f2ec555 introduced pg_class.relwrite to skip operations on
tables created as part of a heap rewrite during DDL. It links such
transient heaps to the original relation OID via this new field in
pg_class but forgot to do anything about toast tables. So, logical
decoding was not able to skip operations on internally created toast
tables. This leads to an error when we tried to decode the WAL for the
next operation for which it appeared that there is a toast data where
actually it didn't have any toast data.
To fix this, we set pg_class.relwrite for internally created toast tables
as well which allowed skipping operations on them during logical decoding.
Author: Bertrand Drouvot
Reviewed-by: David Zhang, Amit Kapila
Backpatch-through: 11, where it was introduced
Discussion: https://postgr.es/m/b5146fb1-ad9e-7d6e-f980-98ed68744a7c@amazon.com
There are two identical error messages about valid value of modulus for
hash partition, in PostgreSQL source code. Commit 0e1275fb07 improved
only one of them so that ambiguous word "positive" was avoided there,
and forgot to improve the other. This commit improves the other.
Which would reduce translator burden.
Back-pach to v11 where the error message exists.
Author: Kyotaro Horiguchi
Reviewed-by: Fujii Masao
Discussion: https://postgr.es/m/20210819.170315.1413060634876301811.horikyota.ntt@gmail.com
The distance in phrase operator must be an integer value between zero
and MAXENTRYPOS inclusive. But previously the error message about
its valid value included the information about its upper limit
but not lower limit (i.e., zero). This commit improves the error message
so that it also includes the information about its lower limit.
Back-patch to v9.6 where full-text phrase search was supported.
Author: Kyotaro Horiguchi
Reviewed-by: Fujii Masao
Discussion: https://postgr.es/m/20210819.170315.1413060634876301811.horikyota.ntt@gmail.com
Regexps like "(.){0}...\1" drew an "invalid backreference number".
That's not unreasonable on its face, since the capture group will
never be matched if it's iterated zero times. However, other engines
such as Perl's don't complain about this, nor do we throw an error for
related cases such as "(.)|\1", even though that backref can never
succeed either. Also, if the zero-iterations case happens at runtime
rather than compile time --- say, "(x)*...\1" when there's no "x" to
be found --- that's not an error, we just deem the backref to not
match. Making this even less defensible, no error was thrown for
nested cases such as "((.)){0}...\2"; and to add insult to injury,
those cases could result in assertion failures instead. (It seems
that nothing especially bad happened in non-assert builds, though.)
Let's just fix it so that no error is thrown and instead the backref
is deemed to never match, so that compile-time detection of no
iterations behaves the same as run-time detection.
Per report from Mark Dilger. This appears to be an aboriginal error
in Spencer's library, so back-patch to all supported versions.
Pre-v14, it turns out to also be necessary to back-patch one aspect of
commits cb76fbd7e/00116dee5, namely to create capture-node subREs with
the begin/end states of their subexpressions, not the current lp/rp
of the outer parseqatom invocation. Otherwise delsub complains that
we're trying to disconnect a state from itself. This is a bit scary
but code examination shows that it's safe: in the pre-v14 code, if we
want to wrap iteration around the subexpression, the first thing we do
is overwrite the atom's begin/end fields with new states. So the
bogus values didn't survive long enough to be used for anything, except
if no iteration is required, in which case it doesn't matter.
Discussion: https://postgr.es/m/A099E4A8-4377-4C64-A98C-3DEDDC075502@enterprisedb.com
The recursion in cdissect() was careless about clearing match data
for capturing parentheses after rejecting a partial match. This
could allow a later back-reference to succeed when by rights it
should fail for lack of a defined referent.
To fix, think a little more rigorously about what the contract
between different levels of cdissect's recursion needs to be.
With the right spec, we can fix this using fewer rather than more
resets of the match data; the key decision being that a failed
sub-match is now explicitly responsible for clearing any matches
it may have set.
There are enough other cross-checks and optimizations in the code
that it's not especially easy to exhibit this problem; usually, the
match will fail as-expected. Plus, regexps that are even potentially
vulnerable are most likely user errors, since there's just not much
point in writing a back-ref that doesn't always have a referent.
These facts perhaps explain why the issue hasn't been detected,
even though it's almost certainly a couple of decades old.
Discussion: https://postgr.es/m/151435.1629733387@sss.pgh.pa.us