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
By default io_uring creates a shared memory mapping for each io_uring
instance, leading to a large number of memory mappings. Unfortunately a large
number of memory mappings slows things down, backend exit is particularly
affected. To address that, newer kernels (6.5) support using user-provided
memory for the memory. By putting the relevant memory into shared memory we
don't need any additional mappings.
On a system with a new enough kernel and liburing, there is no discernible
overhead when doing a pgbench -S -C anymore.
Reported-by: MARK CALLAGHAN <mdcallag@gmail.com>
Reviewed-by: "Burd, Greg" <greg@burd.me>
Reviewed-by: Jim Nasby <jnasby@upgrade.com>
Discussion: https://postgr.es/m/CAFbpF8OA44_UG+RYJcWH9WjF7E3GA6gka3gvH6nsrSnEe9H0NA@mail.gmail.com
Backpatch-through: 18
For an ordered Append or MergeAppend, we need to inject an explicit
sort into any subpath that is not already well enough ordered.
Currently, only explicit full sorts are considered; incremental sorts
are not yet taken into account.
In this patch, for subpaths of an ordered Append or MergeAppend, we
choose to use explicit incremental sort if it is enabled and there are
presorted keys.
The rationale is based on the assumption that incremental sort is
always faster than full sort when there are presorted keys, a premise
that has been applied in various parts of the code. In addition, the
current cost model tends to favor incremental sort as being cheaper
than full sort in the presence of presorted keys, making it reasonable
not to consider full sort in such cases.
No backpatch as this could result in plan changes.
Author: Richard Guo <guofenglinux@gmail.com>
Reviewed-by: Andrei Lepikhov <lepihov@gmail.com>
Reviewed-by: Robert Haas <robertmhaas@gmail.com>
Discussion: https://postgr.es/m/CAMbWs4_V7a2enTR+T3pOY_YZ-FU8ZsFYym2swOz4jNMqmSgyuw@mail.gmail.com
In b0635bfda, I added an early header check to the Meson OAuth support,
which was intended to duplicate the later checks for
HAVE_SYS_[EVENT|EPOLL]_H. However, I implemented the new test via
check_header() -- which tries to compile -- rather than has_header(),
which just looks for the file's existence.
The distinction matters on OpenBSD, where <sys/event.h> can't be
compiled without including prerequisite headers, so -Dlibcurl=enabled
failed on that platform. Switch to has_header() to fix this.
Note that reviewers expressed concern about the difference between our
Autoconf feature tests (which compile headers) and our Meson feature
tests (which do not). I'm not opposed to aligning the two, but I want to
avoid making bigger changes as part of this fix.
Reviewed-by: Peter Eisentraut <peter@eisentraut.org>
Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/flat/CAOYmi+kdR218ke2zu74oTJvzYJcqV1MN5=mGAPqZQuc79HMSVA@mail.gmail.com
Backpatch-through: 18
Commit 2633dae2e4 added some zero padding to various LSNs output
routines so that the low word is always 8 hex digits long, for easy
human consumption. This included the pg_lsn datatype, which breaks the
pg_upgrade test when it compares the pg_dump output of an older version.
Silence this problem by setting the pg_lsn columns to NULL before the
upgrade.
Discussion: https://postgr.es/m/202507071504.xm2r26u7lmzr@alvherre.pgsql
pl/pgsql's notion of an "expression" is very broad, encompassing
any SQL SELECT query that returns a single column and no more than
one row. So there are cases, for example evaluation of an aggregate
function, where the query involves significant work and it'd be useful
to run it with parallel workers. This used to be possible, but
commits 3eea7a0c9 et al unintentionally disabled it.
The simplest fix is to make exec_eval_expr() pass maxtuples = 0
rather than 2 to exec_run_select(). This avoids the new rule that
we will never use parallelism when a nonzero "count" limit is passed
to ExecutorRun(). (Note that the pre-3eea7a0c9 behavior was indeed
unsafe, so reverting that rule is not in the cards.) The reason
for passing 2 before was that exec_eval_expr() will throw an error
if it gets more than one returned row, so we figured that as soon
as we have two rows we know that will happen and we might as well
stop running the query. That choice was cost-free when it was made;
but disabling parallelism is far from cost-free, so now passing 2
amounts to optimizing a failure case at the expense of useful cases.
An expression query that can return more than one row is certainly
broken. People might now need to wait a bit longer to discover such
breakage; but hopefully few will use enormously expensive cases as
their first test of new pl/pgsql logic.
Author: Dipesh Dhameliya <dipeshdhameliya125@gmail.com>
Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/CABgZEgdfbnq9t6xXJnmXbChNTcWFjeM_6nuig41tm327gYi2ig@mail.gmail.com
Backpatch-through: 13
This commit standardizes the output format for LSNs to ensure consistent
representation across various tools and messages. Previously, LSNs were
inconsistently printed as `%X/%X` in some contexts, while others used
zero-padding. This often led to confusion when comparing.
To address this, the LSN format is now uniformly set to `%X/%08X`,
ensuring the lower 32-bit part is always zero-padded to eight
hexadecimal digits.
Author: Japin Li <japinli@hotmail.com>
Reviewed-by: Masahiko Sawada <sawada.mshk@gmail.com>
Reviewed-by: Álvaro Herrera <alvherre@kurilemu.de>
Discussion: https://postgr.es/m/ME0P300MB0445CA53CA0E4B8C1879AF84B641A@ME0P300MB0445.AUSP300.PROD.OUTLOOK.COM
This refactoring is a follow-up of the work done in 5a1dfde833, that
has switched 2PC file names to use FullTransactionIds when written on
disk. This will help with the integration of a follow-up solution
related to the handling of two-phase files during recovery, to address
older defects while reading these from disk after a crash.
This change is useful in itself as it reduces the need to build the
file names from epoch numbers and TransactionIds, because we can use
directly FullTransactionIds from which the 2PC file names are guessed.
So this avoids a lot of back-and-forth between the FullTransactionIds
retrieved from the file names and how these are passed around in the
internal 2PC logic.
Note that the core of the change is the use of a FullTransactionId
instead of a TransactionId in GlobalTransactionData, that tracks 2PC
file information in shared memory. The change in TwoPhaseCallback makes
this commit unfit for stable branches.
Noah has contributed a good chunk of this patch. I have spent some time
on it as well while working on the issues with two-phase state files and
recovery.
Author: Noah Misch <noah@leadboat.com>
Co-Authored-by: Michael Paquier <michael@paquier.xyz>
Discussion: https://postgr.es/m/Z5sd5O9JO7NYNK-C@paquier.xyz
Discussion: https://postgr.es/m/20250116205254.65.nmisch@google.com
libxml2 has deprecated the members of xmlBuffer, and it is recommended
to access them with dedicated routines. We have only one case in the
tree where this shows an impact: xml2/xpath.c where "content" was
getting directly accessed. The rest of the code looked fine, checking
the PostgreSQL code with libxml2 close to the top of its "2.14" branch.
xmlBufferContent() exists since year 2000 based on a check of the
upstream libxml2 tree, so let's switch to it.
Like 400928b83b, backpatch all the way down as this can have an impact
on all the branches already released once newer versions of libxml2 get
more popular.
Reported-by: Walid Ibrahim <walidib@amazon.com>
Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/aGdSdcR4QTjEHX6s@paquier.xyz
Backpatch-through: 13
When estimating the cost/size of a pre-sorted path for a given upper
relation using local stats, this function dereferences the passed-in
PgFdwPathExtraData pointer without checking that it is not NULL. But
that is not a bug as the pointer is guaranteed to be non-NULL in that
case; to avoid confusion, add an Assert to ensure that it is not NULL
before dereferencing it.
Reported-by: Ranier Vilela <ranier.vf@gmail.com>
Author: Etsuro Fujita <etsuro.fujita@gmail.com>
Reviewed-by: Ranier Vilela <ranier.vf@gmail.com>
Discussion: https://postgr.es/m/CAEudQArgiALbV1akQpeZOgim7XP05n%3DbDP1%3DTcOYLA43nRX_vA%40mail.gmail.com
With tables defined like this,
CREATE TABLE ip (id int PRIMARY KEY);
CREATE TABLE ic (id int) INHERITS (ip);
ALTER TABLE ic ALTER id DROP NOT NULL;
pg_upgrade fails during the schema restore phase due to this error:
ERROR: column "id" in child table must be marked NOT NULL
This can only be fixed by marking the child column as NOT NULL before
the upgrade, which could take an arbitrary amount of time (because ic's
data must be scanned). Have pg_upgrade's check mode warn if that
condition is found, so that users know what to adjust before running the
upgrade for real.
Author: Ali Akbar <the.apaan@gmail.com>
Reviewed-by: Justin Pryzby <pryzby@telsasoft.com>
Backpatch-through: 13
Discussion: https://postgr.es/m/CACQjQLoMsE+1pyLe98pi0KvPG2jQQ94LWJ+PTiLgVRK4B=i_jg@mail.gmail.com
Attempting to use commit timestamps during bootstrapping leads to an
assertion failure, that can be reached for example with an initdb -c
that enables track_commit_timestamp. It makes little sense to register
a commit timestamp for a BootstrapTransactionId, so let's disable the
activation of the module in this case.
This problem has been independently reported once by each author of this
commit. Each author has proposed basically the same patch, relying on
IsBootstrapProcessingMode() to skip the use of commit_ts during
bootstrap. The test addition is a suggestion by me, and is applied down
to v16.
Author: Hayato Kuroda <kuroda.hayato@fujitsu.com>
Author: Andy Fan <zhihuifan1213@163.com>
Reviewed-by: Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
Reviewed-by: Fujii Masao <masao.fujii@oss.nttdata.com>
Reviewed-by: Michael Paquier <michael@paquier.xyz>
Discussion: https://postgr.es/m/OSCPR01MB14966FF9E4C4145F37B937E52F5102@OSCPR01MB14966.jpnprd01.prod.outlook.com
Discussion: https://postgr.es/m/87plejmnpy.fsf@163.com
Backpatch-through: 13
Previously, truncating a temporary relation required scanning the entire
local buffer pool once per relation fork to invalidate buffers. This could
be slow, especially with a large local buffers, as the scan was repeated
multiple times.
A similar issue with regular tables (shared buffers) was addressed in
commit 6d05086c0a by scanning the buffer pool only once for all forks.
This commit applies the same optimization to temporary relations,
improving truncation performance.
Author: Daniil Davydov <3danissimo@gmail.com>
Reviewed-by: Michael Paquier <michael@paquier.xyz>
Reviewed-by: Fujii Masao <masao.fujii@gmail.com>
Reviewed-by: Dilip Kumar <dilipbalaut@gmail.com>
Reviewed-by: Maxim Orlov <orlovmg@gmail.com>
Discussion: https://postgr.es/m/CAJDiXggNqsJOH7C5co4jA8nDk8vw-=sokyh5s1_TENWnC6Ofcg@mail.gmail.com
If, after removal of useless null-constant arguments, a CoalesceExpr
has exactly one remaining argument, we can just take that argument as
the result, without bothering to wrap a new CoalesceExpr around it.
This isn't likely to produce any great improvement in runtime per se,
but it can lead to better plans since the planner no longer has to
treat the expression as non-strict.
However, there were a few regression test cases that intentionally
wrote COALESCE(x) as a shorthand way of creating a non-strict
subexpression. To avoid ruining the intent of those tests, write
COALESCE(x,x) instead. (If anyone ever proposes de-duplicating
COALESCE arguments, we'll need another iteration of this arms race.
But it seems pretty unlikely that such an optimization would be
worthwhile.)
Author: Maksim Milyutin <maksim.milyutin@tantorlabs.ru>
Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/8e8573c3-1411-448d-877e-53258b7b2be0@tantorlabs.ru
Using the just-added infrastructure, extend btree_gin to support
cross-type operators in its other opclasses. All of the cross-type
comparison operators supported by the core btree opclasses for
these datatypes are now available for btree_gin indexes as well.
Author: Tom Lane <tgl@sss.pgh.pa.us>
Reviewed-by: Arseniy Mukhin <arseniy.mukhin.dev@gmail.com>
Discussion: https://postgr.es/m/262624.1738460652@sss.pgh.pa.us
Extend the infrastructure in btree_gin.c to permit cross-type
operators, and add the code to support them for the int2, int4,
and int8 opclasses. (To keep this patch digestible, I left
the other datatypes for a separate patch.) This improves the
usability of btree_gin indexes by allowing them to support the
same set of queries that a regular btree index does.
Author: Tom Lane <tgl@sss.pgh.pa.us>
Reviewed-by: Arseniy Mukhin <arseniy.mukhin.dev@gmail.com>
Discussion: https://postgr.es/m/262624.1738460652@sss.pgh.pa.us
Previous commits invented timestamp2timestamptz_opt_overflow,
date2timestamp_opt_overflow, and date2timestamptz_opt_overflow
functions to perform non-error-throwing conversions between
datetime types. This patch completes the set by adding
timestamp2date_opt_overflow, timestamptz2date_opt_overflow,
and timestamptz2timestamp_opt_overflow.
In addition, adjust timestamp2timestamptz_opt_overflow so that it
doesn't throw error if timestamp2tm fails, but treats that as an
overflow case. The situation probably can't arise except with an
invalid timestamp value, and I can't think of a way that that would
happen except data corruption. However, it's pretty silly to have a
function whose entire reason for existence is to not throw errors for
out-of-range inputs nonetheless throw an error for out-of-range input.
The new APIs are not used in this patch, but will be needed in
upcoming btree_gin changes.
Author: Tom Lane <tgl@sss.pgh.pa.us>
Reviewed-by: Arseniy Mukhin <arseniy.mukhin.dev@gmail.com>
Discussion: https://postgr.es/m/262624.1738460652@sss.pgh.pa.us
Commits 8319e5cb5 et al missed the fact that ATPostAlterTypeCleanup
contains three calls to ATPostAlterTypeParse, and the other two
also need protection against passing a relid that we don't yet
have lock on. Add similar logic to those code paths, and add
some test cases demonstrating the need for it.
In v18 and master, the test cases demonstrate that there's a
behavioral discrepancy between stored generated columns and virtual
generated columns: we disallow changing the expression of a stored
column if it's used in any composite-type columns, but not that of
a virtual column. Since the expression isn't actually relevant to
either sort of composite-type usage, this prohibition seems
unnecessary; but changing it is a matter for separate discussion.
For now we are just documenting the existing behavior.
Reported-by: jian he <jian.universality@gmail.com>
Author: jian he <jian.universality@gmail.com>
Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: CACJufxGKJtGNRRSXfwMW9SqVOPEMdP17BJ7DsBf=tNsv9pWU9g@mail.gmail.com
Backpatch-through: 13
Commit 08aa89b326 removed the COMMIT_TS_SETTS WAL record,
leaving xl_commit_ts_set and SizeOfCommitTsSet unused. However,
it missed removing these definitions. This commit cleans up
the leftover code.
Since this is a cleanup rather than a bug fix, it is applied only to
the master branch.
Author: Andy Fan <zhihuifan1213@163.com>
Reviewed-by: Fujii Masao <masao.fujii@gmail.com>
Discussion: https://postgr.es/m/87ecuzmkqf.fsf@163.com
The documentation for pg_replication_slots previously mentioned only
max_slot_wal_keep_size as a condition under which the wal_status column
could show unreserved or lost. However, since commit be87200,
replication slots can also be invalidated due to horizon or wal_level,
and since commit ac0e33136a, idle_replication_slot_timeout can also
trigger this state.
This commit updates the description of the wal_status column to
reflect that max_slot_wal_keep_size is not the only cause of the lost state.
Back-patched to v16, where the additional invalidation cases were introduced.
Author: Fujii Masao <masao.fujii@gmail.com>
Reviewed-by: Hayato Kuroda <kuroda.hayato@fujitsu.com>
Reviewed-by: Nisha Moond <nisha.moond412@gmail.com>
Discussion: https://postgr.es/m/78b34e84-2195-4f28-a151-5d204a382fdd@oss.nttdata.com
Backpatch-through: 16
AlterDomainStmt.subtype used characters for its subtypes of commands,
SET|DROP DEFAULT|NOT NULL and ADD|DROP|VALIDATE CONSTRAINT, which were
hardcoded in a couple of places of the code. The code is improved by
using an enum instead, with the same character values as the original
code.
Note that the field was documented in parsenodes.h and that it forgot to
mention 'V' (VALIDATE CONSTRAINT).
Author: Quan Zongliang <quanzongliang@yeah.net>
Reviewed-by: Peter Eisentraut <peter@eisentraut.org>
Reviewed-by: wenhui qiu <qiuwenhuifx@gmail.com>
Reviewed-by: Tender Wang <tndrwang@gmail.com>
Discussion: https://postgr.es/m/41ff310b-16bd-44b9-a3ef-97e20f14b709@yeah.net
The documentation previously stated that the wal_status column is NULL
if restart_lsn is NULL in the pg_replication_slots view. This is incorrect,
and wal_status can be "lost" even when restart_lsn is NULL.
This commit removes the incorrect description.
Back-patched to all supported versions.
Author: Fujii Masao <masao.fujii@gmail.com>
Reviewed-by: Nisha Moond <nisha.moond412@gmail.com>
Discussion: https://postgr.es/m/c9d23cdc-b5dd-455a-8ee9-f1f24d701d89@oss.nttdata.com
Backpatch-through: 13
