Commit db0d67db2 tweaked sort costing, which however resulted in a
couple plan changes in our regression tests. Most of the new plans were
fine, but partition_aggregate were meant to test parallel plans and the
new plans were serial.
Fix that by lowering parallel_setup_cost to 0, which is enough to switch
to the parallel plan again.
Report and patch by David Rowley.
Author: David Rowley
Reviewed-by: Tomas Vondra
Discussion: https://postgr.es/m/CAApHDvpVFgWzXdtUQkjyOPhNrNvumRi_=ftgS79KeAZ92tnHKQ@mail.gmail.com
XLogPageRead() can retry internally after a pread() system call has
succeeded, in the case of short reads, and page validation failures
while in standby mode (see commit 0668719801). Due to an oversight in
commit 3f1ce973, these cases could leave stale data in the internal
cache of xlogreader.c without marking it invalid. The main defense
against stale cached data on failure to read a page was in the error
handling path of the calling function ReadPageInternal(), but that
wasn't quite enough for errors handled internally by XLogPageRead()'s
retry loop if we then exited with XLREAD_WOULDBLOCK.
1. ReadPageInternal() now marks the cache invalid before calling the
page_read callback, by setting state->readLen to 0. It'll be set to
a non-zero value only after a successful read. It'll stay valid as
long as the caller requests data in the cached range.
2. XLogPageRead() no long performs internal retries while reading
ahead. While such retries should work, the general philosophy is
that we should give up prefetching if anything unusual happens so we
can handle it when recovery catches up, to reduce the complexity of
the system. Let's do that here too.
3. While here, a new function XLogReaderResetError() improves the
separation between xlogrecovery.c and xlogreader.c, where the former
previously clobbered the latter's internal error buffer directly.
The new function makes this more explicit, and also clears a related
flag, without which a standby would needlessly retry in the outer
function.
Thanks to Noah Misch for tracking down the conditions required for a
rare build farm failure in src/bin/pg_ctl/t/003_promote.pl, and
providing a reproducer.
Back-patch to 15.
Reported-by: Noah Misch <noah@leadboat.com>
Discussion: https://postgr.es/m/20220807003627.GA4168930%40rfd.leadboat.com
It was not strictly correct to say that a column list must always include
replica identity columns because that is true for only updates and
deletes.
Author: Peter Smith
Reviwed-by: Vignesh C, Amit Kapila
Backpatch-through: 15, where it was introduced
Discussion: https://postgr.es/m/CAHut+PvOuc9=_4TbASc5=VUqh16UWtFO3GzcKQK_5m1hrW3vqg@mail.gmail.com
The reverts the following and makes some associated cleanups:
commit f79b803dc: Common SQL/JSON clauses
commit f4fb45d15: SQL/JSON constructors
commit 5f0adec25: Make STRING an unreserved_keyword.
commit 33a377608: IS JSON predicate
commit 1a36bc9db: SQL/JSON query functions
commit 606948b05: SQL JSON functions
commit 49082c2cc: RETURNING clause for JSON() and JSON_SCALAR()
commit 4e34747c8: JSON_TABLE
commit fadb48b00: PLAN clauses for JSON_TABLE
commit 2ef6f11b0: Reduce running time of jsonb_sqljson test
commit 14d3f24fa: Further improve jsonb_sqljson parallel test
commit a6baa4bad: Documentation for SQL/JSON features
commit b46bcf7a4: Improve readability of SQL/JSON documentation.
commit 112fdb352: Fix finalization for json_objectagg and friends
commit fcdb35c32: Fix transformJsonBehavior
commit 4cd8717af: Improve a couple of sql/json error messages
commit f7a605f63: Small cleanups in SQL/JSON code
commit 9c3d25e17: Fix JSON_OBJECTAGG uniquefying bug
commit a79153b7a: Claim SQL standard compliance for SQL/JSON features
commit a1e7616d6: Rework SQL/JSON documentation
commit 8d9f9634e: Fix errors in copyfuncs/equalfuncs support for JSON node types.
commit 3c633f32b: Only allow returning string types or bytea from json_serialize
commit 67b26703b: expression eval: Fix EEOP_JSON_CONSTRUCTOR and EEOP_JSONEXPR size.
The release notes are also adjusted.
Backpatch to release 15.
Discussion: https://postgr.es/m/40d2c882-bcac-19a9-754d-4299e1d87ac7@postgresql.org
Primarily, this fixes an incorrect calculation in SlabCheck which was
looking in the wrong byte for the sentinel check. The reason that we've
never noticed this before in the form of a failing sentinel check is
because the pre-check to this always fails because all current core users
of slab contexts have a chunk size which is already MAXALIGNed, therefore
there's never any space for the sentinel byte. It is possible that an
extension needs to use a slab context and if they do with a chunk size
that's not MAXALIGNed, then they'll likely get errors about overwritten
sentinel bytes.
Additionally, this patch changes various calculations which are being done
based on the sizeof(SlabBlock). Currently, sizeof(SlabBlock) is a
multiple of 8, therefore sizeof(SlabBlock) is the same as
MAXALIGN(sizeof(SlabBlock)), however, if we were to ever have to add any
fields to that struct as part of a bug fix, then SlabAlloc could end up
returning a non-MAXALIGNed pointer. To be safe, let's ensure we always
MAXALIGN sizeof(SlabBlock) before using it in any calculations.
This patch has already been applied to master in d5ee4db0e.
Diagnosed-by: Tomas Vondra, Tom Lane
Author: Tomas Vondra, David Rowley
Discussion: https://postgr.es/m/CAA4eK1%2B1JyW5TiL%3DyV-3Uq1CrfnTyn0Xrk5uArt31Z%3D8rgPhXQ%40mail.gmail.com
Backpatch-through: 10
get_database_list() failed to restore the caller's memory context,
instead leaving current context set to TopMemoryContext which is
how CommitTransactionCommand() leaves it. The callers both think
they are using short-lived contexts, for the express purpose of
not having to worry about cleaning up individual allocations.
The net effect therefore is that supposedly short-lived allocations
could accumulate indefinitely in the launcher's TopMemoryContext.
Although this has been broken for a long time, it seems we didn't
have any obvious memory leak here until v15's rearrangement of the
stats logic. I (tgl) am not entirely convinced that there's no
other leak at all, though, and we're surely at risk of adding one
in future back-patched fixes. So back-patch to all supported
branches, even though this may be only a latent bug in pre-v15.
Reid Thompson
Discussion: https://postgr.es/m/972a4e12b68b0f96db514777a150ceef7dcd2e0f.camel@crunchydata.com
If the input word exceeds 1000 bytes, don't pass it to the stemmer;
just return it as-is after case folding. Such an input is surely
not a word in any human language, so whatever the stemmer might
do to it would be pretty dubious in the first place. Adding this
restriction protects us against a known recursion-to-stack-overflow
problem in the Turkish stemmer, and it seems like good insurance
against any other safety or performance issues that may exist in
the Snowball stemmers. (I note, for example, that they contain no
CHECK_FOR_INTERRUPTS calls, so we really don't want them running
for a long time.) The threshold of 1000 bytes is arbitrary.
An alternative definition could have been to treat such words as
stopwords, but that seems like a bigger break from the old behavior.
Per report from Egor Chindyaskin and Alexander Lakhin.
Thanks to Olly Betts for the recommendation to fix it this way.
Discussion: https://postgr.es/m/1661334672.728714027@f473.i.mail.ru
The default of lazy symbol resolution means that when the postmaster
first reaches the select() call in ServerLoop, it'll need to resolve
the link to that libc entry point. NetBSD's dynamic loader takes
an internal lock while doing that, and if a signal interrupts the
operation then there is a risk of self-deadlock should the signal
handler do anything that requires that lock, as several of the
postmaster signal handlers do. The window for this is pretty narrow,
and timing considerations make it unlikely that a signal would arrive
right then anyway. But it's semi-repeatable on slow single-CPU
machines, and in principle the race could happen with any hardware.
The least messy solution to this is to force binding of dynamic
symbols at postmaster start, using the "-z now" linker option.
While we're at it, also use "-z relro" so as to provide a small
security gain.
It's not entirely clear whether any other platforms share this
issue, but for now we'll assume it's NetBSD-specific. (We might
later try to use "-z now" on more platforms for performance
reasons, but that would not likely be something to back-patch.)
Report and patch by me; the idea to fix it this way is from
Andres Freund.
Discussion: https://postgr.es/m/3384826.1661802235@sss.pgh.pa.us
When a PostgreSQL instance performing archive recovery but not using
standby mode is promoted, and the last WAL segment that it attempted
to read ended in a partial record, the previous code would create
invalid WAL on the new timeline. The WAL from the previously timeline
would be copied to the new timeline up until the end of the last valid
record, but instead of beginning to write WAL at immediately
afterwards, the promoted server would write an overwrite contrecord at
the beginning of the next segment. The end of the previous segment
would be left as all-zeroes, resulting in failures if anything tried
to read WAL from that file.
The root of the issue is that ReadRecord() decides whether to set
abortedRecPtr and missingContrecPtr based on the value of StandbyMode,
but ReadRecord() switches to a new timeline based on the value of
ArchiveRecoveryRequested. We shouldn't try to write an overwrite
contrecord if we're switching to a new timeline, so change the test in
ReadRecod() to check ArchiveRecoveryRequested instead.
Code fix by Dilip Kumar. Comments by me incorporating suggested
language from Álvaro Herrera. Further review from Kyotaro Horiguchi
and Sami Imseih.
Discussion: http://postgr.es/m/CAFiTN-t7umki=PK8dT1tcPV=mOUe2vNhHML6b3T7W7qqvvajjg@mail.gmail.com
Discussion: http://postgr.es/m/FB0DEA0B-E14E-43A0-811F-C1AE93D00FF3%40amazon.com
While waiting for slots to become available in wait_on_slots() in
parallel_slot.c, the cancellation always relied on the first connection
in the set to do the job. This could cause problems when this slot's
socket is gone as PQgetCancel() would return NULL in this case. Rather
than always using the first connection, this changes the logic to use
the first valid connection for the cancellation.
Author: Ranier Vilela
Reviewed-by: Justin Pryzby
Discussion: https://postgr.es/m/CAEudQAokk1h_pUwGXsYS4oVOuf35s1O2o3TXGHpV8=AWikvgHA@mail.gmail.com
Backpatch-through: 14
The comment in basebackup.c updated by 33bd4698c1 was actually
obsolete to begin with, since the symbols it was referring to haven't
existed in that header file for quite some time. The header file is
still needed for other reasons, though, so keep the #include, just
drop the comment.
pg_start_backup() and pg_stop_backup() have been respectively renamed to
pg_backup_start() and pg_backup_stop() as of 39969e2, but a few comments
did not get the call.
Reviewed-by: Kyotaro Horiguchi, David Steele
Discussion: https://postgr.es/m/YrqGlj1+4DF3dbZ/@paquier.xyz
SplitToVariants() in the ispell code, lseg_inside_poly() in geo_ops.c,
and regex_selectivity_sub() in selectivity estimation could recurse
until stack overflow; fix by adding check_stack_depth() calls.
So could next() in the regex compiler, but that case is better fixed by
converting its tail recursion to a loop. (We probably get better code
that way too, since next() can now be inlined into its sole caller.)
There remains a reachable stack overrun in the Turkish stemmer, but
we'll need some advice from the Snowball people about how to fix that.
Per report from Egor Chindyaskin and Alexander Lakhin. These mistakes
are old, so back-patch to all supported branches.
Richard Guo and Tom Lane
Discussion: https://postgr.es/m/1661334672.728714027@f473.i.mail.ru
On fast machines, it's possible for applications such as pgbench
to issue connection requests so quickly that the postmaster's
listen queue overflows in the kernel, resulting in unexpected
failures (with not-very-helpful error messages). Most modern OSes
allow the queue size to be increased, so document how to do that.
Per report from Kevin McKibbin.
Discussion: https://postgr.es/m/CADc_NKg2d+oZY9mg4DdQdoUcGzN2kOYXBu-3--RW_hEe0tUV=g@mail.gmail.com
sysctl is more portable than Linux's /proc/sys file tree, and
often easier to use too. That's why most of our docs refer to
sysctl when talking about how to adjust kernel parameters.
Bring the few stragglers into line.
Discussion: https://postgr.es/m/361175.1661187463@sss.pgh.pa.us
Somewhere during the development of the patch acquiring a lock during read
access to variable-numbered stats got lost. The missing lock acquisition won't
cause corruption, but can lead to reading torn values when accessing
stats. Add the missing lock acquisitions.
Reported-by: Greg Stark <stark@mit.edu>
Reviewed-by: "Drouvot, Bertrand" <bdrouvot@amazon.com>
Reviewed-by: Andres Freund <andres@anarazel.de>
Author: Kyotaro Horiguchi <horikyota.ntt@gmail.com>
Discussion: https://postgr.es/m/CAM-w4HMYkM_DkYhWtUGV+qE_rrBxKOzOF0+5faozxO3vXrc9wA@mail.gmail.com
Backpatch: 15-
As such the current usage of & won't produce incorrect results but it
would be better to use && to short-circuit the evaluation of second
condition when the same is not required.
Author: Ranier Vilela
Reviewed-by: Tom Lane, Bharath Rupireddy
Backpatch-through: 15, where it was introduced
Discussion: https://postgr.es/m/CAEudQApL8QcoYwQuutkWKY_h7gBY8F0Xs34YKfc7-G0i83K_pw@mail.gmail.com
Compiling with -Wshadow=compatible-local yields quite a few warnings about
local variables being shadowed by compatible local variables in an inner
scope. Of course, this is perfectly valid in C, but we have had bugs in
the past as a result of developers failing to notice this. af7d270dd is a
recent example.
Here we do a cleanup of warnings we receive from -Wshadow=compatible-local
for code which is new to PostgreSQL 15. We've yet to have the discussion
about if we actually ever want to run that as a standard compilation flag.
We'll need to at least get the number of warnings down to something easier
to manage before we can realistically consider if we want this or not.
This commit is the first step towards reducing the warnings.
The changes being made here are all fairly trivial. Because of that, and
the fact that v15 is still in beta, this is being back-patched into 15.
It seems more risky not to do this as the risk of future bugs is increased
by the additional conflicts that this commit could cause for any future
bug fixes touching the same areas as this commit.
Author: Justin Pryzby
Discussion: https://postgr.es/m/20220817145434.GC26426%40telsasoft.com
Backpatch-through: 15
Consistently avoid trusting a sample of only one page at the point that
VACUUM determines a new reltuples for the target table (though only when
the table is larger than a single page). This is follow-up work to
commit 74388a1a, which added a heuristic to prevent reltuples from
becoming distorted by successive VACUUM operations that each scan only a
single heap page (which was itself more or less a bugfix for an issue in
commit 44fa8488, which simplified VACUUM's handling of scanned pages).
The original bugfix commit did not account for certain remaining cases
that where not affected by its "2% of total relpages" heuristic. This
happened with relations that are small enough that just one of its pages
exceeded the 2% threshold, yet still big enough for VACUUM to deem
skipping most of its pages via the visibility map worthwhile. reltuples
could still become distorted over time with such a table, at least in
scenarios where the VACUUM command is run repeatedly and without the
table itself ever changing.
Author: Peter Geoghegan <pg@bowt.ie>
Discussion: https://postgr.es/m/CAH2-Wzk7d4m3oEbEWkWQKd+gz-eD_peBvdXVk1a_KBygXadFeg@mail.gmail.com
Backpatch: 15-, where the rules for scanned pages changed.
This commit adds or fixes used markups in a couple of places in the docs
(for <command>, <systemitem> and <literal>). While on it, clarify some
of the documentation added recently for archiving modules with
archive_command, that would still be used as default choice if no
external module is defined (though an archive module could as well use
an archive_command).
Author: Maxim Yablokov
Discussion: https://postgr.es/m/b47ec4e8-6f6a-2aba-038e-d5db150b245e@postgrespro.ru
Backpatch-through: 15
