The grammar was a little shaky and confusing here, so word-smith it
a bit. Also, adjust the comments in pg_ident.conf.sample to use the
same terminology as the SGML docs, in particular "DATABASE-USERNAME"
not "PG-USERNAME".
Back-patch appropriate subsets. I did not risk changing
pg_ident.conf.sample in released branches, but it still seems OK
to change it in v18.
Reported-by: Alexey Shishkin <alexey.shishkin@enterprisedb.com>
Author: Tom Lane <tgl@sss.pgh.pa.us>
Reviewed-by: David G. Johnston <david.g.johnston@gmail.com>
Discussion: https://postgr.es/m/175206279327.3157504.12519088928605422253@wrigleys.postgresql.org
Backpatch-through: 13
It's impossible to reach this case with either ra or rb being
WJB_DONE, because our earlier checks that the structure and
length of the inputs match should guarantee that we reach their
ends simultaneously. However, the comment completely fails to
explain this, and the Asserts don't cover it either. The comment
is pretty obscure anyway, so rewrite it, and extend the Asserts
to reject WJB_DONE.
This is only cosmetic, so no need for back-patch.
Author: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/0c623e8a204187b87b4736792398eaf1@postgrespro.ru
Because not every path through JsonbIteratorNext() sets val->type,
some compilers complain that compareJsonbContainers() is comparing
possibly-uninitialized values. The paths that don't set it return
WJB_DONE, WJB_END_ARRAY, or WJB_END_OBJECT, so it's clear by
manual inspection that the "(ra == rb)" code path is safe, and
indeed we aren't seeing warnings about that. But the (ra != rb)
case is much less obviously safe. In Assert-enabled builds it
seems that the asserts rejecting WJB_END_ARRAY and WJB_END_OBJECT
persuade gcc 15.x not to warn, which makes little sense because
it's impossible to believe that the compiler can prove of its
own accord that ra/rb aren't WJB_DONE here. (In fact they never
will be, so the code isn't wrong, but why is there no warning?)
Without Asserts, the appearance of warnings is quite unsurprising.
We discussed fixing this by converting those two Asserts into
pg_assume, but that seems not very satisfactory when it's so unclear
why the compiler is or isn't warning: the warning could easily
reappear with some other compiler version. Let's fix it in a less
magical, more future-proof way by changing JsonbIteratorNext()
so that it always does set val->type. The cost of that should be
pretty negligible, and it makes the function's API spec less squishy.
Reported-by: Erik Rijkers <er@xs4all.nl>
Author: Tom Lane <tgl@sss.pgh.pa.us>
Reviewed-by: Andres Freund <andres@anarazel.de>
Discussion: https://postgr.es/m/988bf1bc-3f1f-99f3-bf98-222f1cd9dc5e@xs4all.nl
Discussion: https://postgr.es/m/0c623e8a204187b87b4736792398eaf1@postgrespro.ru
Backpatch-through: 13
Previously, when pressing Tab after GRANT or REVOKE ... ON LARGE OBJECT
or ON FOREIGN SERVER, TO or FROM was incorrectly suggested by psql's
tab-completion. This was not appropriate, as those clauses are not valid
at that point.
This commit fixes the issue by preventing TO and FROM from being offered
immediately after those specific GRANT/REVOKE statements.
Author: Yugo Nagata <nagata@sraoss.co.jp>
Reviewed-by: Fujii Masao <masao.fujii@gmail.com>
Discussion: https://postgr.es/m/20250408122857.b2b06dde4e6a08290af02336@sraoss.co.jp
Previously, amcheck could produce misleading error message when
a partitioned index was passed to functions like bt_index_check().
For example, bt_index_check() with a partitioned btree index produced:
ERROR: expected "btree" index as targets for verification
DETAIL: Relation ... is a btree index.
Reporting "expected btree index as targets" even when the specified
index was a btree was confusing. In this case, the function should fail
since the partitioned index specified is not valid target. This commit
improves the error reporting to better reflect this actual issue. Now,
bt_index_check() with a partitioned index, the error message is:
ERROR: expected index as targets for verification
DETAIL: This operation is not supported for partitioned indexes.
This commit also applies the following minor changes:
- Simplifies index_checkable() by using get_am_name() to retrieve
the access method name.
- Changes index_checkable() from extern to static, as it is only used
in verify_common.c.
- Updates the error code for invalid indexes to
ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE,
aligning with usage in similar modules like pgstattuple.
Author: Masahiro Ikeda <ikedamsh@oss.nttdata.com>
Reviewed-by: Fujii Masao <masao.fujii@gmail.com>
Discussion: https://postgr.es/m/8829854bbfc8635ddecd0846bb72dfda@oss.nttdata.com
If the system-name field of a pg_ident.conf line is a regex
containing capturing parentheses, you can write \1 in the
user-name field to represent the captured part of the system
name. But what happens if you write \1 more than once?
The only reasonable expectation IMO is that each \1 gets
replaced, but presently our code replaces only the first.
Fix that.
Also, improve the tests for this feature to exercise cases
where a non-empty string needs to be substituted for \1.
The previous testing didn't inspire much faith that it
was verifying correct operation of the substitution code.
Given the lack of field complaints about this, I don't
feel a need to back-patch.
Reported-by: David G. Johnston <david.g.johnston@gmail.com>
Author: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/CAKFQuwZu6kZ8ZPvJ3pWXig+6UX4nTVK-hdL_ZS3fSdps=RJQQQ@mail.gmail.com
This commit adds the possibility to specify a service file in a
connection string, using a new option called "servicefile". The parsing
of the service file happens so as things are done in this order of
priority:
- The servicefile connection option.
- Environment variable PGSERVICEFILE.
- Default path, depending on the HOME environment.
Note that in the last default case, we need to fill in "servicefile" for
the connection's PQconninfoOption to let clients know which service file
has been used for the connection. Some TAP tests are added, with a few
tweaks required for Windows when using URIs or connection option values,
for the location paths.
Author: Torsten Förtsch <tfoertsch123@gmail.com>
Co-authored-by: Ryo Kanbayashi <kanbayashi.dev@gmail.com>
Discussion: https://postgr.es/m/CAKkG4_nCjx3a_F3gyXHSPWxD8Sd8URaM89wey7fG_9g7KBkOCQ@mail.gmail.com
The values of the "result" variables in these functions are
always integers; using a float8 variable accomplishes nothing
except to incur useless conversions to and from float. While
that wastes a few nanoseconds, these functions aren't all that
time-critical. But it seems worth fixing to remove possible
reader confusion.
Also, in the case of date2isoyear(), "result" is a very poorly
chosen variable name because it is *not* the function's result.
Rename it to "week", and do the same in date2isoweek() for
consistency.
Since this is mostly cosmetic, there seems little need
for back-patch.
Author: Sergey Fukanchik <s.fukanchik@postgrespro.ru>
Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/6323a-68726500-1-7def9d00@137821581
method_worker.c installed SignalHandlerForConfigReload, but it failed to
actually process reload requests. That hasn't yet produced any concrete
problem reports in terms of GUC changes it should have cared about in
v18, but it was inconsistent.
It did cause problems for a couple of patches in development that need
IO workers to react to ALTER SYSTEM + pg_reload_conf(). Fix extracted
from one of those patches.
Back-patch to 18.
Reported-by: Dmitry Dolgov <9erthalion6@gmail.com>
Discussion: https://postgr.es/m/sh5uqe4a4aqo5zkkpfy5fobe2rg2zzouctdjz7kou4t74c66ql%40yzpkxb7pgoxf
In an ancient ancestor of this code, the postmaster assigned IDs to IO
workers. Now it tracks them in an unordered array and doesn't know
their IDs, so it might be confusing to readers that it still referred to
their indexes as IDs.
No change in behavior, just variable name and error message cleanup.
Back-patch to 18.
Discussion: https://postgr.es/m/CA%2BhUKG%2BwbaZZ9Nwc_bTopm4f-7vDmCwLk80uKDHj9mq%2BUp0E%2Bg%40mail.gmail.com
Adopt PgAioXXX convention for pgaio module type names. Rename a
function that didn't use a pgaio_worker_ submodule prefix. Rename the
internal submit function's arguments to match the indirectly relevant
function pointer declaration and nearby examples. Rename the array of
handle IDs in PgAioSubmissionQueue to sqes, a term of art seen in the
systems it emulates, also clarifying that they're not IO handle
pointers as the old name might imply.
No change in behavior, just type, variable and function name cleanup.
Back-patch to 18.
Discussion: https://postgr.es/m/CA%2BhUKG%2BwbaZZ9Nwc_bTopm4f-7vDmCwLk80uKDHj9mq%2BUp0E%2Bg%40mail.gmail.com
getid() and putid(), which parse and deparse role names within ACL
input/output, applied isalnum() to see if a character within a role
name requires quoting. They did this even for non-ASCII characters,
which is problematic because the results would depend on encoding,
locale, and perhaps even platform. So it's possible that putid()
could elect not to quote some string that, later in some other
environment, getid() will decide is not a valid identifier, causing
dump/reload or similar failures.
To fix this in a way that won't risk interoperability problems
with unpatched versions, make getid() treat any non-ASCII as a
legitimate identifier character (hence not requiring quotes),
while making putid() treat any non-ASCII as requiring quoting.
We could remove the resulting excess quoting once we feel that
no unpatched servers remain in the wild, but that'll be years.
A lesser problem is that getid() did the wrong thing with an input
consisting of just two double quotes (""). That has to represent an
empty string, but getid() read it as a single double quote instead.
The case cannot arise in the normal course of events, since we don't
allow empty-string role names. But let's fix it while we're here.
Although we've not heard field reports of problems with non-ASCII
role names, there's clearly a hazard there, so back-patch to all
supported versions.
Reported-by: Peter Eisentraut <peter@eisentraut.org>
Author: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/3792884.1751492172@sss.pgh.pa.us
Backpatch-through: 13
Commit b0635bfda split off the CPPFLAGS/LDFLAGS/LDLIBS for libcurl into
their own separate Makefile variables, but I neglected to move the
existing AC_CHECKs for Curl into a place where they would make use of
those variables. They instead tested the system libcurl, which 1) is
unhelpful if a different Curl is being used for the build and 2) will
fail the build entirely if no system libcurl exists. Correct the order
of operations here.
Reported-by: Ivan Kush <ivan.kush@tantorlabs.com>
Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us>
Reviewed-by: Ivan Kush <ivan.kush@tantorlabs.com>
Discussion: https://postgr.es/m/8a611028-51a1-408c-b592-832e2e6e1fc9%40tantorlabs.com
Backpatch-through: 18
This option, which is disabled by default, can be used to request
the checkpoint also flush dirty buffers of unlogged relations. As
with the MODE option, the server may consolidate the options for
concurrently requested checkpoints. For example, if one session
uses (FLUSH_UNLOGGED FALSE) and another uses (FLUSH_UNLOGGED TRUE),
the server may perform one checkpoint with FLUSH_UNLOGGED enabled.
Author: Christoph Berg <myon@debian.org>
Reviewed-by: Laurenz Albe <laurenz.albe@cybertec.at>
Reviewed-by: Fujii Masao <masao.fujii@oss.nttdata.com>
Reviewed-by: Dilip Kumar <dilipbalaut@gmail.com>
Discussion: https://postgr.es/m/aDnaKTEf-0dLiEfz%40msg.df7cb.de
This option may be set to FAST (the default) to request the
checkpoint be completed as fast as possible, or SPREAD to request
the checkpoint be spread over a longer interval (based on the
checkpoint-related configuration parameters). Note that the server
may consolidate the options for concurrently requested checkpoints.
For example, if one session requests a "fast" checkpoint and
another requests a "spread" checkpoint, the server may perform one
"fast" checkpoint.
Author: Christoph Berg <myon@debian.org>
Reviewed-by: Andres Freund <andres@anarazel.de>
Reviewed-by: Fujii Masao <masao.fujii@oss.nttdata.com>
Reviewed-by: Laurenz Albe <laurenz.albe@cybertec.at>
Reviewed-by: Dilip Kumar <dilipbalaut@gmail.com>
Discussion: https://postgr.es/m/aDnaKTEf-0dLiEfz%40msg.df7cb.de
This commit adds the boilerplate code for supporting a list of
options in CHECKPOINT commands. No actual options are supported
yet, but follow-up commits will add support for MODE and
FLUSH_UNLOGGED. While at it, this commit refactors the code for
executing CHECKPOINT commands to its own function since it's about
to become significantly larger.
Author: Christoph Berg <myon@debian.org>
Reviewed-by: Fujii Masao <masao.fujii@oss.nttdata.com>
Discussion: https://postgr.es/m/aDnaKTEf-0dLiEfz%40msg.df7cb.de
The new name more accurately reflects the effects of this flag on a
requested checkpoint. Checkpoint-related log messages (i.e., those
controlled by the log_checkpoints configuration parameter) will now
say "fast" instead of "immediate", too. Likewise, references to
"immediate" checkpoints in the documentation have been updated to
say "fast". This is preparatory work for a follow-up commit that
will add a MODE option to the CHECKPOINT command.
Author: Christoph Berg <myon@debian.org>
Discussion: https://postgr.es/m/aDnaKTEf-0dLiEfz%40msg.df7cb.de
The new name more accurately relects the effects of this flag on a
requested checkpoint. Checkpoint-related log messages (i.e., those
controlled by the log_checkpoints configuration parameter) will now
say "flush-unlogged" instead of "flush-all", too. This is
preparatory work for a follow-up commit that will add a
FLUSH_UNLOGGED option to the CHECKPOINT command.
Author: Christoph Berg <myon@debian.org>
Discussion: https://postgr.es/m/aDnaKTEf-0dLiEfz%40msg.df7cb.de
We already forced LC_MESSAGES to C in order to get consistent
message output, but that isn't enough to stabilize messages
that include %f or similar formatting.
I'm a bit surprised that this hasn't come up before. Perhaps
we ought to back-patch this change, but I'll refrain for now.
Reported-by: Bernd Helmle <mailings@oopsware.de>
Author: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/6f024eaa7885eddf5e0eb4ba1d095fbc7146519b.camel@oopsware.de
Previously, the check_hook functions for max_slot_wal_keep_size and
idle_replication_slot_timeout would incorrectly raise an ERROR for values
set in postgresql.conf during upgrade, even though those values were not
actively used in the upgrade process.
To prevent logical slot invalidation during upgrade, we used to set
special values for these GUCs. Now, instead of relying on those values, we
directly prevent WAL removal and logical slot invalidation caused by
max_slot_wal_keep_size and idle_replication_slot_timeout.
Note: PostgreSQL 17 does not include the idle_replication_slot_timeout
GUC, so related changes were not backported.
BUG #18979
Reported-by: jorsol <jorsol@gmail.com>
Author: Dilip Kumar <dilipbalaut@gmail.com>
Reviewed by: vignesh C <vignesh21@gmail.com>
Reviewed by: Alvaro Herrera <alvherre@alvh.no-ip.org>
Backpatch-through: 17, where it was introduced
Discussion: https://postgr.es/m/219561.1751826409@sss.pgh.pa.us
Discussion: https://postgr.es/m/18979-a1b7fdbb7cd181c6@postgresql.org
Previously, the idle_replication_slot_timeout parameter used minutes
as its unit, based on the assumption that values would typically exceed
one minute in production environments. However, this caused unexpected
behavior: specifying a value below 30 seconds would round down to 0,
effectively disabling the timeout. This could be surprising to users.
To allow finer-grained control and avoid such confusion, this commit changes
the unit of idle_replication_slot_timeout to seconds. Larger values can
still be specified easily using standard time suffixes, for example,
'24h' for 24 hours.
Back-patch to v18 where idle_replication_slot_timeout was added.
Reported-by: Gunnar Morling <gunnar.morling@googlemail.com>
Author: Fujii Masao <masao.fujii@gmail.com>
Reviewed-by: Laurenz Albe <laurenz.albe@cybertec.at>
Reviewed-by: David G. Johnston <david.g.johnston@gmail.com>
Reviewed-by: Amit Kapila <amit.kapila16@gmail.com>
Reviewed-by: Hayato Kuroda <kuroda.hayato@fujitsu.com>
Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/CADGJaX_0+FTguWpNSpgVWYQP_7MhoO0D8=cp4XozSQgaZ40Odw@mail.gmail.com
Backpatch-through: 18
When sslkeylogfile has been set but the file fails to open in an
otherwise successful connection, the log entry added to the conn
object is never printed. Instead print the error on stderr for
increased visibility. This is a debugging tool so using stderr
for logging is appropriate. Also while there, remove the umask
call in the callback as it's not useful.
Issues noted by Peter Eisentraut in post-commit review, backpatch
down to 18 when support for sslkeylogfile was added
Author: Daniel Gustafsson <daniel@yesql.se>
Reported-by: Peter Eisentraut <peter@eisentraut.org>
Reviewed-by: Peter Eisentraut <peter@eisentraut.org>
Discussion: https://postgr.es/m/70450bee-cfaa-48ce-8980-fc7efcfebb03@eisentraut.org
Backpatch-through: 18
Commit a45c78e328 moved large object metadata from SECTION_PRE_DATA
to SECTION_DATA but neglected to move PRIO_LARGE_OBJECT in
dbObjectTypePriorities accordingly. While this hasn't produced any
known live bugs, it causes problems for a proposed patch that
optimizes upgrades with many large objects. Fixing the priority
might also make the topological sort step marginally faster by
reducing the number of ordering violations that have to be fixed.
Reviewed-by: Nitin Motiani <nitinmotiani@google.com>
Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/aBkQLSkx1zUJ-LwJ%40nathan
Discussion: https://postgr.es/m/aG_5DBCjdDX6KAoD%40nathan
Backpatch-through: 17
During the development cycle of v18, btree_gist has been bumped once to
1.8 for the addition of translate_cmptype support functions (originally
7406ab623f, renamed in 32edf732e8). 1.9 has added sortsupport
functions (e4309f73f6).
There is no need for two version bumps in a module for a single major
release of PostgreSQL. This commit unifies both upgrades to a single
SQL script, downgrading btree_gist to 1.8.
Author: Paul A. Jungwirth <pj@illuminatedcomputing.com>
Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/13c61807-f702-4afe-9a8d-795e2fd40923@illuminatedcomputing.com
Backpatch-through: 18
This function can be used to retrieve the information about all the
injection points attached to a cluster, providing coverage for
InjectionPointList() introduced in 7b2eb72b1b.
The original proposal turned around a system function, but that would
not be backpatchable to stable branches. It was also a bit weird to
have a system function that fails depending on if the build allows
injection points or not.
Reviewed-by: Aleksander Alekseev <aleksander@timescale.com>
Reviewed-by: Rahila Syed <rahilasyed90@gmail.com>
Discussion: https://postgr.es/m/Z_xYkA21KyLEHvWR@paquier.xyz
Since b0635bfda, libpq uses dlopen() and related functions. On some
platforms these are not supplied by libc, but by a separate library
libdl, in which case we need to make sure that that dependency is
known to the linker. Meson seems to take care of that automatically,
but the Makefile didn't cater for it.
Author: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/1328170.1752082586@sss.pgh.pa.us
Backpatch-through: 18
Increase the size of the "direct" histogram to 10K elements,
so that we can precisely track loop times up to 10 microseconds.
(Going further than that seems pretty uninteresting, even for
very old and slow machines.)
Relabel "Per loop time" as "Average loop time" for clarity.
Pre-zero the histogram arrays to make sure that they are loaded
into processor cache and any copy-on-write overhead has happened
before we enter the timing loop. Also use unlikely() to keep
the compiler from thinking that the clock-went-backwards case
is part of the hot loop. Neither of these hacks made a lot of
difference on my own machine, but they seem like they might help
on some platforms.
Discussion: https://postgr.es/m/be0339cc-1ae1-4892-9445-8e6d8995a44d@eisentraut.org
This commit adds a new system view that provides information about
entries in the dynamic shared memory (DSM) registry. Specifically,
it returns the name, type, and size of each entry. Note that since
we cannot discover the size of dynamic shared memory areas (DSAs)
and hash tables backed by DSAs (dshashes) without first attaching
to them, the size column is left as NULL for those.
Bumps catversion.
Author: Florents Tselai <florents.tselai@gmail.com>
Reviewed-by: Sungwoo Chang <swchangdev@gmail.com>
Discussion: https://postgr.es/m/4D445D3E-81C5-4135-95BB-D414204A0AB4%40gmail.com
Commit c273d9d8ce reworked tab-completion of COPY and \copy in psql
and added support for completing options within WITH clauses. However,
the same COPY options were suggested for both COPY TO and COPY FROM
commands, even though some options are only valid for one or the
other.
This commit separates the COPY options for COPY FROM and COPY TO
commands to provide more accurate auto-completion suggestions.
Back-patch to v14 where tab-completion for COPY and \copy options
within WITH clauses was first supported.
Author: Atsushi Torikoshi <torikoshia@oss.nttdata.com>
Reviewed-by: Yugo Nagata <nagata@sraoss.co.jp>
Discussion: https://postgr.es/m/079e7a2c801f252ae8d522b772790ed7@oss.nttdata.com
Backpatch-through: 14
This test corresponds to the case of a "service" defined in a service
file, that libpq is not able to support in parseServiceFile().
This has come up during the review of a patch to add more features in
this area, useful on its own. Piece extracted from a larger patch by
the same author.
Author: Ryo Kanbayashi <kanbayashi.dev@gmail.com>
Discussion: https://postgr.es/m/Zz2AE7NKKLIZTtEh@paquier.xyz
This routine has been introduced as a shortcut to be able to retrieve a
service name from an active connection, for psql. Per discussion, and
as it is only used by psql, let's remove it to not clutter the libpq API
more than necessary.
The logic in psql is replaced by lookups of PQconninfoOption for the
active connection, instead, updated each time the variables are synced
by psql, the prompt shortcut relying on the variable synced.
Reported-by: Noah Misch <noah@leadboat.com>
Discussion: https://postgr.es/m/20250706161319.c1.nmisch@google.com
Backpatch-through: 18
What we want in these places is "xmlChar *volatile ptr",
not "volatile xmlChar *ptr". The former means that the
pointer variable itself needs to be treated as volatile,
while the latter says that what it points to is volatile.
Since the point here is to ensure that the pointer variables
don't go crazy after a longjmp, it's the former semantics
that we need. The misplacement of "volatile" also led
to needing to cast away volatile in some places.
Also fix a number of places where variables that are assigned to
within a PG_TRY and then used after it were not initialized or
not marked as volatile. (A few buildfarm members were issuing
"may be used uninitialized" warnings about some of these variables,
which is what drew my attention to this area.) In most cases
these variables were being set as the last step within the PG_TRY
block, which might mean that we could get away without the "volatile"
marking. But doing that seems unsafe and is definitely not per our
coding conventions.
These problems seem to have come in with 732061150, so no need
for back-patch.
Most of our platforms have better-than-microsecond timing resolution,
so the original definition of this program is getting less and less
useful. Make it report nanoseconds not microseconds. Also, add a
second output table that reports the exact observed timing durations,
up to a limit of 1024 ns; and be sure to report the largest observed
duration.
The documentation for this program included a lot of system-specific
details that now seem largely obsolete. Move all that text to the
PG wiki, where perhaps it will be easier to maintain and update.
Also, improve the TAP test so that it actually runs a short standard
run, allowing most of the code to be exercised; its coverage before
was abysmal.
Author: Hannu Krosing <hannuk@google.com>
Co-authored-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/be0339cc-1ae1-4892-9445-8e6d8995a44d@eisentraut.org
Per buildfarm member culicidae, the query checking for stats reported by
the WAL summarizer related to WAL reads is proving to be unstable.
Instead of a one-time query, this commit replaces the logic with a
polling query checking for the WAL read stats, making the test more
reliable on machines that could be slow with the stats reports.
This test has been introduced in f4694e0f35, so backpatch down to v18.
Reported-by: Alexander Lakhin <exclusion@gmail.com>
Reviewed-by: Alexander Lakhin <exclusion@gmail.com>
Discussion: https://postgr.es/m/f35ba3db-fca7-4693-bc35-6db64488e4b1@gmail.com
Backpatch-through: 18
