public inbox for [email protected]
help / color / mirror / Atom feedpgsql: Doc: add information about partition locking
9+ messages / 2 participants
[nested] [flat]
* pgsql: Doc: add information about partition locking
@ 2025-04-02 01:03 David Rowley <[email protected]>
0 siblings, 1 reply; 9+ messages in thread
From: David Rowley @ 2025-04-02 01:03 UTC (permalink / raw)
To: [email protected]
Doc: add information about partition locking
The documentation around locking of partitions for the executor startup
phase of run-time partition pruning wasn't clear about which partitions
were being locked. Fix that.
Reviewed-by: Tender Wang <[email protected]>
Discussion: https://postgr.es/m/CAApHDvp738G75HfkKcfXaf3a8s%3D6mmtOLh46tMD0D2hAo1UCzA%40mail.gmail.com
Backpatch-through: 13
Branch
------
master
Details
-------
https://git.postgresql.org/pg/commitdiff/121d774caea4c93c8b36fb20a17ef774e60894d6
Modified Files
--------------
doc/src/sgml/ddl.sgml | 8 +++++++-
1 file changed, 7 insertions(+), 1 deletion(-)
^ permalink raw reply [nested|flat] 9+ messages in thread
* pgsql: Doc: add information about partition locking
@ 2025-04-02 01:04 David Rowley <[email protected]>
0 siblings, 0 replies; 9+ messages in thread
From: David Rowley @ 2025-04-02 01:04 UTC (permalink / raw)
To: [email protected]
Doc: add information about partition locking
The documentation around locking of partitions for the executor startup
phase of run-time partition pruning wasn't clear about which partitions
were being locked. Fix that.
Reviewed-by: Tender Wang <[email protected]>
Discussion: https://postgr.es/m/CAApHDvp738G75HfkKcfXaf3a8s%3D6mmtOLh46tMD0D2hAo1UCzA%40mail.gmail.com
Backpatch-through: 13
Branch
------
REL_17_STABLE
Details
-------
https://git.postgresql.org/pg/commitdiff/e962d6d12b7e8185775da26ef0f77a3ac63d18a0
Modified Files
--------------
doc/src/sgml/ddl.sgml | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
^ permalink raw reply [nested|flat] 9+ messages in thread
* pgsql: Doc: add information about partition locking
@ 2025-04-02 01:04 David Rowley <[email protected]>
0 siblings, 0 replies; 9+ messages in thread
From: David Rowley @ 2025-04-02 01:04 UTC (permalink / raw)
To: [email protected]
Doc: add information about partition locking
The documentation around locking of partitions for the executor startup
phase of run-time partition pruning wasn't clear about which partitions
were being locked. Fix that.
Reviewed-by: Tender Wang <[email protected]>
Discussion: https://postgr.es/m/CAApHDvp738G75HfkKcfXaf3a8s%3D6mmtOLh46tMD0D2hAo1UCzA%40mail.gmail.com
Backpatch-through: 13
Branch
------
REL_16_STABLE
Details
-------
https://git.postgresql.org/pg/commitdiff/9b34f10ee050a115d2e02c1bec6de1bf31933970
Modified Files
--------------
doc/src/sgml/ddl.sgml | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
^ permalink raw reply [nested|flat] 9+ messages in thread
* pgsql: Doc: add information about partition locking
@ 2025-04-02 01:04 David Rowley <[email protected]>
0 siblings, 0 replies; 9+ messages in thread
From: David Rowley @ 2025-04-02 01:04 UTC (permalink / raw)
To: [email protected]
Doc: add information about partition locking
The documentation around locking of partitions for the executor startup
phase of run-time partition pruning wasn't clear about which partitions
were being locked. Fix that.
Reviewed-by: Tender Wang <[email protected]>
Discussion: https://postgr.es/m/CAApHDvp738G75HfkKcfXaf3a8s%3D6mmtOLh46tMD0D2hAo1UCzA%40mail.gmail.com
Backpatch-through: 13
Branch
------
REL_15_STABLE
Details
-------
https://git.postgresql.org/pg/commitdiff/2be0fe94bf20e9125a47aa216ee9b07d96ff0fae
Modified Files
--------------
doc/src/sgml/ddl.sgml | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
^ permalink raw reply [nested|flat] 9+ messages in thread
* pgsql: Doc: add information about partition locking
@ 2025-04-02 01:05 David Rowley <[email protected]>
0 siblings, 0 replies; 9+ messages in thread
From: David Rowley @ 2025-04-02 01:05 UTC (permalink / raw)
To: [email protected]
Doc: add information about partition locking
The documentation around locking of partitions for the executor startup
phase of run-time partition pruning wasn't clear about which partitions
were being locked. Fix that.
Reviewed-by: Tender Wang <[email protected]>
Discussion: https://postgr.es/m/CAApHDvp738G75HfkKcfXaf3a8s%3D6mmtOLh46tMD0D2hAo1UCzA%40mail.gmail.com
Backpatch-through: 13
Branch
------
REL_14_STABLE
Details
-------
https://git.postgresql.org/pg/commitdiff/d501e7ba5e50b86a3769595d5cfbfea281312af6
Modified Files
--------------
doc/src/sgml/ddl.sgml | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
^ permalink raw reply [nested|flat] 9+ messages in thread
* pgsql: Doc: add information about partition locking
@ 2025-04-02 01:05 David Rowley <[email protected]>
0 siblings, 0 replies; 9+ messages in thread
From: David Rowley @ 2025-04-02 01:05 UTC (permalink / raw)
To: [email protected]
Doc: add information about partition locking
The documentation around locking of partitions for the executor startup
phase of run-time partition pruning wasn't clear about which partitions
were being locked. Fix that.
Reviewed-by: Tender Wang <[email protected]>
Discussion: https://postgr.es/m/CAApHDvp738G75HfkKcfXaf3a8s%3D6mmtOLh46tMD0D2hAo1UCzA%40mail.gmail.com
Backpatch-through: 13
Branch
------
REL_13_STABLE
Details
-------
https://git.postgresql.org/pg/commitdiff/ebbdaf1fd59d3bad4bb0aee346ad6f8a225549d1
Modified Files
--------------
doc/src/sgml/ddl.sgml | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
^ permalink raw reply [nested|flat] 9+ messages in thread
* Re: pgsql: Doc: add information about partition locking
@ 2026-03-27 07:09 Amit Langote <[email protected]>
parent: David Rowley <[email protected]>
0 siblings, 1 reply; 9+ messages in thread
From: Amit Langote @ 2026-03-27 07:09 UTC (permalink / raw)
To: David Rowley <[email protected]>; +Cc: [email protected]
Hi David,
On Wed, Apr 2, 2025 at 10:03 AM David Rowley <[email protected]> wrote:
>
> Doc: add information about partition locking
>
> The documentation around locking of partitions for the executor startup
> phase of run-time partition pruning wasn't clear about which partitions
> were being locked. Fix that.
>
> Reviewed-by: Tender Wang <[email protected]>
> Discussion: https://postgr.es/m/CAApHDvp738G75HfkKcfXaf3a8s%3D6mmtOLh46tMD0D2hAo1UCzA%40mail.gmail.com
> Backpatch-through: 13
>
> Branch
> ------
> master
>
> Details
> -------
> https://git.postgresql.org/pg/commitdiff/121d774caea4c93c8b36fb20a17ef774e60894d6
- <command>EXPLAIN</command> output.
+ <command>EXPLAIN</command> output. The query planner obtains locks for
+ all partitions which are part of the plan. However, when the executor
+ uses a cached plan, locks are only obtained on the partitions which
+ remain after partition pruning done during the initialization phase of
+ execution, i.e., the ones shown in the <command>EXPLAIN</command>
+ output and not the ones referred to by the
+ <quote>Subplans Removed</quote> property.
</para>
</listitem>
This text was correct when committed, but became incorrect after I
reverted 525392d57 in May 2025. Sorry for not catching it sooner.
I think we should change the text in both master and REL_18_STABLE to
match what you added in the older branches. I can change it back to
this when we get pruning-aware locking again.
--
Thanks, Amit Langote
^ permalink raw reply [nested|flat] 9+ messages in thread
* Re: pgsql: Doc: add information about partition locking
@ 2026-03-27 07:15 Amit Langote <[email protected]>
parent: Amit Langote <[email protected]>
0 siblings, 1 reply; 9+ messages in thread
From: Amit Langote @ 2026-03-27 07:15 UTC (permalink / raw)
To: David Rowley <[email protected]>; +Cc: [email protected]
On Fri, Mar 27, 2026 at 4:09 PM Amit Langote <[email protected]> wrote:
> Hi David,
>
> On Wed, Apr 2, 2025 at 10:03 AM David Rowley <[email protected]> wrote:
> >
> > Doc: add information about partition locking
> >
> > The documentation around locking of partitions for the executor startup
> > phase of run-time partition pruning wasn't clear about which partitions
> > were being locked. Fix that.
> >
> > Reviewed-by: Tender Wang <[email protected]>
> > Discussion: https://postgr.es/m/CAApHDvp738G75HfkKcfXaf3a8s%3D6mmtOLh46tMD0D2hAo1UCzA%40mail.gmail.com
> > Backpatch-through: 13
> >
> > Branch
> > ------
> > master
> >
> > Details
> > -------
> > https://git.postgresql.org/pg/commitdiff/121d774caea4c93c8b36fb20a17ef774e60894d6
>
> - <command>EXPLAIN</command> output.
> + <command>EXPLAIN</command> output. The query planner obtains locks for
> + all partitions which are part of the plan. However, when the executor
> + uses a cached plan, locks are only obtained on the partitions which
> + remain after partition pruning done during the initialization phase of
> + execution, i.e., the ones shown in the <command>EXPLAIN</command>
> + output and not the ones referred to by the
> + <quote>Subplans Removed</quote> property.
> </para>
> </listitem>
>
> This text was correct when committed, but became incorrect after I
> reverted 525392d57 in May 2025. Sorry for not catching it sooner.
>
> I think we should change the text in both master and REL_18_STABLE to
> match what you added in the older branches. I can change it back to
> this when we get pruning-aware locking again.
Will apply the attached.
--
Thanks, Amit Langote
Attachments:
[application/octet-stream] v1-0001-Doc-fix-stale-text-about-partition-locking-with-c.patch (1.9K, 2-v1-0001-Doc-fix-stale-text-about-partition-locking-with-c.patch)
download | inline diff:
From 6cca1e1b7f2945db63863e236ca62a1d6291d493 Mon Sep 17 00:00:00 2001
From: Amit Langote <[email protected]>
Date: Fri, 27 Mar 2026 16:12:23 +0900
Subject: [PATCH v1] Doc: fix stale text about partition locking with cached
plans
Commit 121d774caea added text to master describing pruning-aware
locking behavior introduced by 525392d57. That behavior was
reverted in May 2025, making the text incorrect. Replace it with
the text used in back branches, which correctly describes current
behavior: pruned partitions are still locked at the beginning of
execution.
Discussion: https://postgr.es/m/CA+HiwqFT0fPPoYBr0iUFWNB-Og7bEXB9hB=6ogk_qD9=OM8Vbw@mail.gmail.com
---
doc/src/sgml/ddl.sgml | 10 +++-------
1 file changed, 3 insertions(+), 7 deletions(-)
diff --git a/doc/src/sgml/ddl.sgml b/doc/src/sgml/ddl.sgml
index 8421ecace1b..bd8cb461cba 100644
--- a/doc/src/sgml/ddl.sgml
+++ b/doc/src/sgml/ddl.sgml
@@ -5416,13 +5416,9 @@ EXPLAIN SELECT count(*) FROM measurement WHERE logdate >= DATE '2008-01-01';
It is possible to determine the number of partitions which were
removed during this phase by observing the
<quote>Subplans Removed</quote> property in the
- <command>EXPLAIN</command> output. The query planner obtains locks for
- all partitions which are part of the plan. However, when the executor
- uses a cached plan, locks are only obtained on the partitions which
- remain after partition pruning done during the initialization phase of
- execution, i.e., the ones shown in the <command>EXPLAIN</command>
- output and not the ones referred to by the
- <quote>Subplans Removed</quote> property.
+ <command>EXPLAIN</command> output. It's important to note that any
+ partitions removed by the partition pruning done at this stage are
+ still locked at the beginning of execution.
</para>
</listitem>
--
2.47.3
^ permalink raw reply [nested|flat] 9+ messages in thread
* Re: pgsql: Doc: add information about partition locking
@ 2026-03-30 01:32 Amit Langote <[email protected]>
parent: Amit Langote <[email protected]>
0 siblings, 0 replies; 9+ messages in thread
From: Amit Langote @ 2026-03-30 01:32 UTC (permalink / raw)
To: David Rowley <[email protected]>; +Cc: [email protected]
On Fri, Mar 27, 2026 at 4:15 PM Amit Langote <[email protected]> wrote:
> On Fri, Mar 27, 2026 at 4:09 PM Amit Langote <[email protected]> wrote:
> > Hi David,
> >
> > On Wed, Apr 2, 2025 at 10:03 AM David Rowley <[email protected]> wrote:
> > >
> > > Doc: add information about partition locking
> > >
> > > The documentation around locking of partitions for the executor startup
> > > phase of run-time partition pruning wasn't clear about which partitions
> > > were being locked. Fix that.
> > >
> > > Reviewed-by: Tender Wang <[email protected]>
> > > Discussion: https://postgr.es/m/CAApHDvp738G75HfkKcfXaf3a8s%3D6mmtOLh46tMD0D2hAo1UCzA%40mail.gmail.com
> > > Backpatch-through: 13
> > >
> > > Branch
> > > ------
> > > master
> > >
> > > Details
> > > -------
> > > https://git.postgresql.org/pg/commitdiff/121d774caea4c93c8b36fb20a17ef774e60894d6
> >
> > - <command>EXPLAIN</command> output.
> > + <command>EXPLAIN</command> output. The query planner obtains locks for
> > + all partitions which are part of the plan. However, when the executor
> > + uses a cached plan, locks are only obtained on the partitions which
> > + remain after partition pruning done during the initialization phase of
> > + execution, i.e., the ones shown in the <command>EXPLAIN</command>
> > + output and not the ones referred to by the
> > + <quote>Subplans Removed</quote> property.
> > </para>
> > </listitem>
> >
> > This text was correct when committed, but became incorrect after I
> > reverted 525392d57 in May 2025. Sorry for not catching it sooner.
> >
> > I think we should change the text in both master and REL_18_STABLE to
> > match what you added in the older branches. I can change it back to
> > this when we get pruning-aware locking again.
>
> Will apply the attached.
Pushed.
--
Thanks, Amit Langote
^ permalink raw reply [nested|flat] 9+ messages in thread
end of thread, other threads:[~2026-03-30 01:32 UTC | newest]
Thread overview: 9+ messages (download: mbox mbox.gz follow: Atom feed)
-- links below jump to the message on this page --
2025-04-02 01:03 pgsql: Doc: add information about partition locking David Rowley <[email protected]>
2026-03-27 07:09 ` Amit Langote <[email protected]>
2026-03-27 07:15 ` Amit Langote <[email protected]>
2026-03-30 01:32 ` Amit Langote <[email protected]>
2025-04-02 01:04 pgsql: Doc: add information about partition locking David Rowley <[email protected]>
2025-04-02 01:04 pgsql: Doc: add information about partition locking David Rowley <[email protected]>
2025-04-02 01:04 pgsql: Doc: add information about partition locking David Rowley <[email protected]>
2025-04-02 01:05 pgsql: Doc: add information about partition locking David Rowley <[email protected]>
2025-04-02 01:05 pgsql: Doc: add information about partition locking David Rowley <[email protected]>
This inbox is served by agora; see mirroring instructions
for how to clone and mirror all data and code used for this inbox