Commit Graph

15161 Commits

Author SHA1 Message Date
Bruce Momjian ff18b8d1b1 doc: mention pg_upgrade extension script
Since commit e462856a7a, pg_upgrade automatically creates a script to
update extensions, so mention that instead of ALTER EXTENSION.

Backpatch-through: 9.6
2021-08-08 21:05:46 -04:00
Tom Lane 410c5a08df Doc: remove bogus <indexterm> items.
Copy-and-pasteo in 665c5855e, evidently.  The 9.6 docs toolchain
whined about duplicate index entries, though our modern toolchain
doesn't.  In any case, these GUCs surely are not about the
default settings of these values.
2021-08-08 15:35:30 -04:00
Tom Lane 6432cf9265 Release notes for 13.4, 12.8, 11.13, 10.18, 9.6.23. 2021-08-08 14:35:19 -04:00
Peter Eisentraut d3ad6566a1 Fix wording 2021-08-06 22:05:41 +02:00
Tom Lane 2f38ec6a15 First-draft release notes for 13.4.
As usual, the release notes for older branches will be made by cutting
these down, but put them up for community review first.
2021-08-06 14:54:59 -04:00
Etsuro Fujita 388a81bf4d postgres_fdw: Fix issues with generated columns in foreign tables.
postgres_fdw imported generated columns from the remote tables as plain
columns, and caused failures like "ERROR: cannot insert a non-DEFAULT
value into column "foo"" when inserting into the foreign tables, as it
tried to insert values into the generated columns.  To fix, we do the
following under the assumption that generated columns in a postgres_fdw
foreign table are defined so that they represent generated columns in
the underlying remote table:

* Send DEFAULT for the generated columns to the foreign server on insert
  or update, not generated column values computed on the local server.
* Add to postgresImportForeignSchema() an option "import_generated" to
  include column generated expressions in the definitions of foreign
  tables imported from a foreign server.  The option is true by default.

The assumption seems reasonable, because that would make a query of the
postgres_fdw foreign table return values for the generated columns that
are consistent with the generated expression.

While here, fix another issue in postgresImportForeignSchema(): it tried
to include column generated expressions as column default expressions in
the foreign table definitions when the import_default option was enabled.

Per bug #16631 from Daniel Cherniy.  Back-patch to v12 where generated
columns were added.

Discussion: https://postgr.es/m/16631-e929fe9db0ffc7cf%40postgresql.org
2021-08-05 20:00:02 +09:00
Bruce Momjian 1dd8400206 doc: interval spill method for units greater than months
Units are _truncated_ to months, but only in back branches since the
recent commit.

Reported-by: Bryn Llewellyn

Discussion: https://postgr.es/m/BDAE4B56-3337-45A2-AC8A-30593849D6C0@yugabyte.com

Backpatch-through: 9.6 to 14
2021-08-03 12:17:58 -04:00
Bruce Momjian 0e6cf3c6f4 pg_upgrade: improve docs about extension upgrades
The previous wording was unclear about the steps needed to upgrade
extensions, and how to update them after pg_upgrade.

Reported-by: Dave Cramer

Discussion: https://postgr.es/m/CADK3HHKawwbOcGwMGnDuAf3-U8YfvTcS8jqDv3UM=niijs3MMA@mail.gmail.com

Backpatch-through: 9.6
2021-08-03 11:27:33 -04:00
Bruce Momjian 7134b8cacc doc: mention inheritance's tableoid can be used in partitioning
Previously tableoid was not mentioned in the partition doc section.  We
only had a link to the "all the normal rules" of inheritance section.

Reported-by: michal.palenik@freemap.sk

Discussion: https://postgr.es/m/162627031219.693.11508199541771263335@wrigleys.postgresql.org

Backpatch-through: 10
2021-08-03 11:11:51 -04:00
Bruce Momjian 073069075f doc: add example of using pg_dump with GNU split and gzip
This is only possible with GNU split, not other versions like BSD split.

Reported-by: jim@jdoherty.net

Discussion: https://postgr.es/m/162653459215.701.6323855956817776386@wrigleys.postgresql.org

Backpatch-through: 9.6
2021-08-03 10:57:32 -04:00
John Naylor 171bf1cea5 Fix range check in ECPG numeric to int conversion
The previous coding guarded against -INT_MAX instead of INT_MIN,
leading to -2147483648 being rejected as out of range.

Per bug #17128 from Kevin Sweet

Discussion: https://www.postgresql.org/message-id/flat/17128-55a8a879727a3e3a%40postgresql.org
Reviewed-by: Tom Lane
Backpatch to all supported branches
2021-07-30 16:18:59 -04:00
David Rowley aa1e9211ec Doc: Clarify lock levels taken during ATTACH PARTITION
It wasn't all that clear which lock levels, if any, would be held on the
DEFAULT partition during an ATTACH PARTITION operation.

Also, clarify which locks will be taken if the DEFAULT partition or the
table being attached are themselves partitioned tables.

Here I'm only backpatching to v12 as before then we obtained an ACCESS
EXCLUSIVE lock on the partitioned table.  It seems much less relevant to
mention which locks are taken on other tables when the partitioned table
itself is locked with an ACCESS EXCLUSIVE lock.

Author: Matthias van de Meent, David Rowley
Discussion: https://postgr.es/m/CAEze2WiTB6iwrV8W_J=fnrnZ7fowW3qu-8iQ8zCHP3FiQ6+o-A@mail.gmail.com
Backpatch-through: 12
2021-07-28 15:01:40 +12:00
Fujii Masao 92913fc290 Avoid using ambiguous word "non-negative" in error messages.
The error messages using the word "non-negative" are confusing
because it's ambiguous about whether it accepts zero or not.
This commit improves those error messages by replacing it with
less ambiguous word like "greater than zero" or
"greater than or equal to zero".

Also this commit added the note about the word "non-negative" to
the error message style guide, to help writing the new error messages.

When postgres_fdw option fetch_size was set to zero, previously
the error message "fetch_size requires a non-negative integer value"
was reported. This error message was outright buggy. Therefore
back-patch to all supported versions where such buggy error message
could be thrown.

Reported-by: Hou Zhijie
Author: Bharath Rupireddy
Reviewed-by: Kyotaro Horiguchi, Fujii Masao
Discussion: https://postgr.es/m/OS0PR01MB5716415335A06B489F1B3A8194569@OS0PR01MB5716.jpnprd01.prod.outlook.com
2021-07-28 01:21:52 +09:00
Bruce Momjian d629fcf4b3 doc: for various substring funcs, document if only first match
Reported-by: troy@frericks.us

Discussion: https://postgr.es/m/162614304115.701.2392941350859387646@wrigleys.postgresql.org

Backpatch-through: 13
2021-07-26 22:54:35 -04:00
Bruce Momjian 0a5e708e2b pg_resetxlog: add option to set oldest xid & use by pg_upgrade
Add pg_resetxlog -u option to set the oldest xid in pg_control.
Previously -x set this value be -2 billion less than the -x value.
However, this causes the server to immediately scan all relation's
relfrozenxid so it can advance pg_control's oldest xid to be inside the
autovacuum_freeze_max_age range, which is inefficient and might disrupt
diagnostic recovery.  pg_upgrade will use this option to better create
the new cluster to match the old cluster.

Reported-by: Jason Harvey, Floris Van Nee

Discussion: https://postgr.es/m/20190615183759.GB239428@rfd.leadboat.com, 87da83168c644fd9aae38f546cc70295@opammb0562.comp.optiver.com

Author: Bertrand Drouvot

Backpatch-through: 9.6
2021-07-26 22:38:14 -04:00
Tom Lane 8344979d5b Doc: improve documentation about exponentiation operator.
Now that we're not having to wedge this into the straitjacket of
the old operator table format, we can add another example to
clarify the point about left-to-right associativity.

Per suggestion from mdione at grulic.org.ar.

https://postgr.es/m/162661954599.693.13700316547731859171@wrigleys.postgresql.org
2021-07-21 18:03:52 -04:00
Fujii Masao df3264e73f doc: Document that only superusers can use pg_import_system_collations().
Back-patch to v10 where pg_import_system_collations() was added.

Author: Atsushi Torikoshi
Reviewed-by: Fujii Masao
Discussion: https://postgr.es/m/b7f484692a3e283710032e68b7f40617@oss.nttdata.com
2021-07-21 13:53:24 +09:00
Michael Paquier e159368027 doc: Mention CASCADE/RESTRICT for DROP STATISTICS
This grammar has no effect as there are no dependencies on statistics,
but it is supported by the parser.  This is more consistent with the
other DROP commands.

Author: Vignesh C
Discussion: https://postgr.es/m/CALDaNm1LA=yNmzcSfy+0oe6CEAgsxXRf_-UutE3ZncFi8QkFNQ@mail.gmail.com
Backpatch-through: 10
2021-07-19 12:39:53 +09:00
Tom Lane 35e9d26a1b Doc: document the current-transaction-modes GUCs.
We had documentation of default_transaction_isolation et al,
but for some reason not of transaction_isolation et al.
AFAICS this is just an ancient oversight, so repair.

Per bug #17077 from Yanliang Lei.

Discussion: https://postgr.es/m/17077-ade8e166a01e1374@postgresql.org
2021-07-17 11:52:54 -04:00
Peter Eisentraut 0455f35fd4 doc: Fix typo in function prototype 2021-07-12 22:17:24 +02:00
Fujii Masao 306c5e05e2 doc: Fix description about pg_stat_statements.track_planning.
This commit fixes wrong wording like "a fewer kinds"
in the description about track_planning option.

Back-patch to v13 where pg_stat_statements.track_planning was added.

Author: Justin Pryzby
Reviewed-by: Julien Rouhaud, Fujii Masao
Discussion: https://postgr.es/m/20210418233615.GB7256@telsasoft.com
2021-07-07 21:55:26 +09:00
Tom Lane fa44348105 Doc: add info about timestamps with fractional-minute UTC offsets.
Our code has supported fractional-minute UTC offsets for ages, but
there was no mention of the possibility in the main docs, and only
a very indirect reference in Appendix B.  Improve that.

Discussion: https://postgr.es/m/162543102827.697.5755498651217979813@wrigleys.postgresql.org
2021-07-06 10:34:51 -04:00
Amit Kapila 27621cc555 Doc: Hash Indexes.
A new chapter for Hash Indexes, designed to help users understand how
they work and when to use them.

Backpatch-through 10 where we have made hash indexes durable.

Author: Simon Riggs
Reviewed-By: Justin Pryzby, Amit Kapila
Discussion: https://postgr.es/m/CANbhV-HRjNPYgHo--P1ewBrFJ-GpZPb9_25P7=Wgu7s7hy_sLQ@mail.gmail.com
2021-07-05 09:52:05 +05:30
Michael Paquier 39a21ce06b doc: Mention requirement to --enable-tap-tests on section for TAP tests
Author: Greg Sabino Mullane
Discussion: https://postgr.es/m/CAKAnmmJYH2FBn_+Vwd2FD5SaKn8hjhAXOCHpZc6n4wXaUaW_SA@mail.gmail.com
Backpatch-through: 9.6
2021-07-04 20:59:14 +09:00
David Rowley 409d9390e8 Doc: mention that VACUUM can't utilize over 1GB of RAM
Document that setting maintenance_work_mem to values over 1GB has no
effect on VACUUM.

Reported-by: Martín Marqués
Author: Laurenz Albe
Discussion: https://postgr.es/m/CABeG9LsZ2ozUMcqtqWu_-GiFKB17ih3p8wBHXcpfnHqhCnsc7A%40mail.gmail.com
Backpatch-through: 9.6, oldest supported release
2021-07-04 22:29:57 +12:00
Bruce Momjian 650e635901 doc: adjust "cities" example to be consistent with other SQL
Reported-by: tom@crystae.net

Discussion: https://postgr.es/m/162345756191.14472.9754568432103008703@wrigleys.postgresql.org

Backpatch-through: 9.6
2021-07-02 20:42:46 -04:00
Andrew Dunstan 8d2be14028
add missing tag from commit b8c4261e5e 2021-07-01 15:40:42 -04:00
Andrew Dunstan bd0be7f7a4
Add new make targets world-bin and install-world-bin
These are the same as world and install-world respectively, but without
building or installing the documentation. There are many reasons for
wanting to be able to do this, including speed, lack of documentation
building tools, and wanting to build other formats of the documentation.
Plans for simplifying the buildfarm client code include using these
targets.

Backpatch to all live branches.

Discussion: https://postgr.es/m/6a421136-d462-b043-a8eb-e75b2861f3df@dunslane.net
2021-07-01 14:31:10 -04:00
Peter Eisentraut 372a2806eb doc: Change reloption data type spelling for consistency
Use "floating point" rather than "float4", like everywhere else in
this context.

Author: Shinya11.Kato@nttdata.com
Discussion: https://www.postgresql.org/message-id/flat/TYAPR01MB28965989AF84B57FC351B97BC40F9@TYAPR01MB2896.jpnprd01.prod.outlook.com
2021-06-25 08:12:52 +02:00
Amit Kapila 7a4ecefe9d Doc: Update caveats in synchronous logical replication.
Reported-by: Simon Riggs
Author: Takamichi Osumi
Reviewed-by: Amit Kapila
Backpatch-through: 9.6
Discussion: https://www.postgresql.org/message-id/20210222222847.tpnb6eg3yiykzpky@alap3.anarazel.de
2021-06-24 09:31:51 +05:30
Tom Lane 9aa06956ea Doc: fix confusion about LEAKPROOF in syntax summaries.
The syntax summaries for CREATE FUNCTION and allied commands
made it look like LEAKPROOF is an alternative to
IMMUTABLE/STABLE/VOLATILE, when of course it is an orthogonal
option.  Improve that.

Per gripe from aazamrafeeque0.  Thanks to David Johnston for
suggestions.

Discussion: https://postgr.es/m/162444349581.694.5818572718530259025@wrigleys.postgresql.org
2021-06-23 14:27:13 -04:00
Amit Kapila 9f7bba2629 Document a few caveats in synchronous logical replication.
In a synchronous logical setup, locking [user] catalog tables can cause
deadlock. This is because logical decoding of transactions can lock
catalog tables to access them so exclusively locking those in transactions
can lead to deadlock. To avoid this users must refrain from having
exclusive locks on catalog tables.

Author: Takamichi Osumi
Reviewed-by: Vignesh C, Amit Kapila
Backpatch-through: 9.6
Discussion: https://www.postgresql.org/message-id/20210222222847.tpnb6eg3yiykzpky%40alap3.anarazel.de
2021-06-17 10:52:01 +05:30
Tom Lane c1fd756fd2 Avoid misbehavior when persisting a non-stable cursor.
PersistHoldablePortal has long assumed that it should store the
entire output of the query-to-be-persisted, which requires rewinding
and re-reading the output.  This is problematic if the query is not
stable: we might get different row contents, or even a different
number of rows, which'd confuse the cursor state mightily.

In the case where the cursor is NO SCROLL, this is very easy to
solve: just store the remaining query output, without any rewinding,
and tweak the portal's cursor state to match.  Aside from removing
the semantic problem, this could be significantly more efficient
than storing the whole output.

If the cursor is scrollable, there's not much we can do, but it
was already the case that scrolling a volatile query's result was
pretty unsafe.  We can just document more clearly that getting
correct results from that is not guaranteed.

There are already prohibitions in place on using SCROLL with
FOR UPDATE/SHARE, which is one way for a SELECT query to have
non-stable results.  We could imagine prohibiting SCROLL when
the query contains volatile functions, but that would be
expensive to enforce.  Moreover, it could break applications
that work just fine, if they have functions that are in fact
stable but the user neglected to mark them so.  So settle for
documenting the hazard.

While this problem has existed in some guise for a long time,
it got a lot worse in v11, which introduced the possibility
of persisting plpgsql cursors (perhaps implicit ones) even
when they violate the rules for what can be marked WITH HOLD.
Hence, I've chosen to back-patch to v11 but not further.

Per bug #17050 from Алексей Булгаков.

Discussion: https://postgr.es/m/17050-f77aa827dc85247c@postgresql.org
2021-06-08 17:50:15 -04:00
Tom Lane b4c027b5f5 Doc: fix bogus intarray index example.
The siglen parameter is provided by gist__intbig_ops not
gist__int_ops.

Simon Norris

Discussion: https://postgr.es/m/11BF2AA9-17AE-432A-AFE1-584FB9FB079D@hillcrestgeo.ca
2021-06-03 21:07:21 -04:00
Michael Paquier 6131cb144f doc: Fix link reference for PGSSLMAXPROTOCOLVERSION
The link was pointing to the minimum protocol version.  Incorrect as of
ff8ca5f.

Author: Daniel Gustafsson
Discussion: https://postgr.es/m/F893F184-C645-4C21-A2BA-583441B7288F@yesql.se
Backpatch-through: 13
2021-06-04 09:33:22 +09:00
Michael Paquier 0ab64ab318 doc: Fix description of some GUCs in docs and postgresql.conf.sample
The following parameters have been imprecise, or incorrect, about their
description (PGC_POSTMASTER or PGC_SIGHUP):
- autovacuum_work_mem (docs, as of 9.6~)
- huge_page_size (docs, as of 14~)
- max_logical_replication_workers (docs, as of 10~)
- max_sync_workers_per_subscription (docs, as of 10~)
- min_dynamic_shared_memory (docs, as of 14~)
- recovery_init_sync_method (postgresql.conf.sample, as of 14~)
- remove_temp_files_after_crash (docs, as of 14~)
- restart_after_crash (docs, as of 9.6~)
- ssl_min_protocol_version (docs, as of 12~)
- ssl_max_protocol_version (docs, as of 12~)

This commit adjusts the description of all these parameters to be more
consistent with the practice used for the others.

Revewed-by: Justin Pryzby
Discussion: https://postgr.es/m/YK2ltuLpe+FbRXzA@paquier.xyz
Backpatch-through: 9.6
2021-05-27 14:58:09 +09:00
Amit Kapila 9012e5594c Improve docs and error messages for parallel vacuum.
The error messages, docs, and one of the options were using
'parallel degree' to indicate parallelism used by vacuum command. We
normally use 'parallel workers' at other places so change it for parallel
vacuum accordingly.

Author: Bharath Rupireddy
Reviewed-by: Dilip Kumar, Amit Kapila
Backpatch-through: 13
Discussion: https://postgr.es/m/CALj2ACWz=PYrrFXVsEKb9J1aiX4raA+UBe02hdRp_zqDkrWUiw@mail.gmail.com
2021-05-25 09:40:16 +05:30
Tom Lane 6a4c071568 Doc: correct erroneous entry in this week's minor release notes.
The patch to disallow a NULL specification in combination with
GENERATED ... AS IDENTITY applied to both ALWAYS and BY DEFAULT
variants of that clause, not only the former.

Noted by Shay Rojansky.

Discussion: https://postgr.es/m/CADT4RqAwD3A=RvGiQU9AiTK-6VeuXcycwPHmJPv_OBCJFYOEww@mail.gmail.com
2021-05-14 17:36:20 -04:00
Tom Lane dc714c120e Prevent infinite insertion loops in spgdoinsert().
Formerly we just relied on operator classes that assert longValuesOK
to eventually shorten the leaf value enough to fit on an index page.
That fails since the introduction of INCLUDE-column support (commit
09c1c6ab4), because the INCLUDE columns might alone take up more
than a page, meaning no amount of leaf-datum compaction will get
the job done.  At least with spgtextproc.c, that leads to an infinite
loop, since spgtextproc.c won't throw an error for not being able
to shorten the leaf datum anymore.

To fix without breaking cases that would otherwise work, add logic
to spgdoinsert() to verify that the leaf tuple size is decreasing
after each "choose" step.  Some opclasses might not decrease the
size on every single cycle, and in any case, alignment roundoff
of the tuple size could obscure small gains.  Therefore, allow
up to 10 cycles without additional savings before throwing an
error.  (Perhaps this number will need adjustment, but it seems
quite generous right now.)

As long as we've developed this logic, let's back-patch it.
The back branches don't have INCLUDE columns to worry about, but
this seems like a good defense against possible bugs in operator
classes.  We already know that an infinite loop here is pretty
unpleasant, so having a defense seems to outweigh the risk of
breaking things.  (Note that spgtextproc.c is actually the only
known opclass with longValuesOK support, so that this is all moot
for known non-core opclasses anyway.)

Per report from Dilip Kumar.

Discussion: https://postgr.es/m/CAFiTN-uxP_soPhVG840tRMQTBmtA_f_Y8N51G7DKYYqDh7XN-A@mail.gmail.com
2021-05-14 15:07:34 -04:00
Alexander Korotkov ff91d3a22b Improve documentation example for jsonpath like_regex operator
Make sample like_regex match string values of the root object instead of the
whole document.  The corrected example seems to represent a more relevant
use case.

Backpatch to 12, when jsonpath was introduced.

Discussion: https://postgr.es/m/13440f8b-4c1f-5875-c8e3-f3f65606af2f%40xs4all.nl
Author: Erik Rijkers
Reviewed-by: Michael Paquier, Alexander Korotkov
Backpatch-through: 12
2021-05-13 16:18:03 +03:00
Tom Lane 9b93a33f45 Last-minute updates for release notes.
Security: CVE-2021-32027, CVE-2021-32028, CVE-2021-32029
2021-05-10 13:10:29 -04:00
Tom Lane 55fe672a92 Release notes for 13.3, 12.7, 11.12, 10.17, 9.6.22. 2021-05-09 13:31:40 -04:00
Tom Lane 7f4bab7f4a First-draft release notes for 13.3.
As usual, the release notes for older branches will be made by cutting
these down, but put them up for community review first.
2021-05-07 12:19:41 -04:00
Alvaro Herrera f518c3df4e
Document lock level used by ALTER TABLE VALIDATE CONSTRAINT
Backpatch all the way back to 9.6.

Author: Simon Riggs <simon.riggs@enterprisedb.com>
Discussion: https://postgr.es/m/CANbhV-EwxvdhHuOLdfG2ciYrHOHXV=mm6=fD5aMhqcH09Li3Tg@mail.gmail.com
2021-05-06 17:17:56 -04:00
Tom Lane 3eeadc425c Doc: add an example of a self-referential foreign key to ddl.sgml.
While we've always allowed such cases, the documentation didn't
say you could do it.

Discussion: https://postgr.es/m/161969805833.690.13680986983883602407@wrigleys.postgresql.org
2021-04-30 15:37:56 -04:00
Tom Lane 7c810bd028 Doc: update libpq's documentation for PQfn().
Mention specifically that you can't call aggregates, window functions,
or procedures this way (the inability to call SRFs was already
mentioned).

Also, the claim that PQfn doesn't support NULL arguments or results
has been a lie since we invented protocol 3.0.  Not sure why this
text was never updated for that, but do it now.

Discussion: https://postgr.es/m/2039442.1615317309@sss.pgh.pa.us
2021-04-30 15:10:06 -04:00
Alvaro Herrera 896cedc7d5
Improve documentation for default_tablespace on partitioned tables
Backpatch to 12, where 87259588d0 introduced the current behavior.

Per note from Justin Pryzby.

Co-authored-by: Justin Pryzby <pryzby@telsasoft.com>
Discussion: https://postgr.es/m/20210416143135.GI3315@telsasoft.com
2021-04-29 11:31:24 -04:00
Tom Lane 7bbcfb4d58 Doc: fix discussion of how to get real Julian Dates.
Somehow I'd convinced myself that rotating to UTC-12 was the way
to do this, but upon further review, it's definitely UTC+12.

Discussion: https://postgr.es/m/1197050.1619123213@sss.pgh.pa.us
2021-04-28 10:03:28 -04:00
Tom Lane ec5bab9217 Doc: document EXTRACT(JULIAN ...), improve Julian Date explanation.
For some reason, the "julian" option for extract()/date_part() has
never gotten listed in the manual.  Also, while Appendix B mentioned
in passing that we don't conform to the usual astronomical definition
that a Julian date starts at noon UTC, it was kind of vague about what
we do instead.  Clarify that, and add an example showing how to get
the astronomical definition if you want it.

It's been like this for ages, so back-patch to all supported branches.

Discussion: https://postgr.es/m/1197050.1619123213@sss.pgh.pa.us
2021-04-26 11:50:35 -04:00
Fujii Masao 8019fcb00f doc: Fix obsolete description about pg_basebackup.
Previously it was documented that if using "-X none" option there was
no guarantee that all required WAL files were archived at the end of
pg_basebackup when taking a backup from the standby. But this limitation
was removed by commit 52f8a59dd9. Now, even when taking a backup
from the standby, pg_basebackup can wait for all required WAL files
to be archived. Therefore this commit removes such obsolete
description from the docs.

Also this commit adds new description about the limitation when
taking a backup from the standby, into the docs. The limitation is that
pg_basebackup cannot force the standbfy to switch to a new WAL file
at the end of backup, which may cause pg_basebackup to wait a long
time for the last required WAL file to be switched and archived,
especially when write activity on the primary is low.

Back-patch to v10 where the issue was introduced.

Reported-by: Kyotaro Horiguchi
Author: Kyotaro Horiguchi, Fujii Masao
Reviewed-by: Kyotaro Horiguchi, Fujii Masao
Discussion: https://postgr.es/m/20210420.133235.1342729068750553399.horikyota.ntt@gmail.com
2021-04-23 15:46:42 +09:00