From: Alex Friedman <alexf01@gmail.com>
To: Sami Imseih <samimseih@gmail.com>
Cc: pgsql-hackers@lists.postgresql.org
Subject: Re: Doc: clarify possibility of ephemeral discrepancies between state and wait_event in pg_stat_activity
Date: Wed, 26 Feb 2025 23:01:48 +0200
Message-ID: <ba25c8f6-eafa-4f6c-a436-5a0824bf9593@gmail.com> (raw)
In-Reply-To: <CAA5RZ0ssBs_x=nbrgOViw+E8gBcG0eLHraid1kH-Eg+rx5wm-w@mail.gmail.com>
References: <8a275154-a654-44b0-ab37-197802f04c7b@gmail.com>
<CAA5RZ0ssBs_x=nbrgOViw+E8gBcG0eLHraid1kH-Eg+rx5wm-w@mail.gmail.com>
On 26/02/2025 22:00, Sami Imseih wrote:
> If we do need to document anything, which I am not convinced we should,
> it should be more generic.
Thanks for the feedback, I've attached a v2 patch which has wording that's a bit
more generic.
It's also worth noting that pg_locks already has a full paragraph explaining
inconsistencies, so in my opinion it's worth it at least mentioning something
similar here for pg_stat_activity.
Best regards,
Alex Friedman
Attachments:v2-0001-Clarify-possibility-of-ephemeral-discrepancies-be.patch (text/plain, 1.3K) download
From fbbfc623e16ed97176c0ccf0ebc534d118e9f252 Mon Sep 17 00:00:00 2001
From: Alex Friedman <alexf01@gmail.com>
Date: Wed, 26 Feb 2025 19:59:59 +0200
Subject: [PATCH v2] Clarify possibility of ephemeral discrepancies between
state and wait_event in pg_stat_activity.
---
doc/src/sgml/monitoring.sgml | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)
diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgmlindex 9178f1d34ef..de49769d407 100644--- a/doc/src/sgml/monitoring.sgml+++ b/doc/src/sgml/monitoring.sgml@@ -1016,7 +1016,11 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser
it may or may not be <literal>waiting</literal> on some event. If the state
is <literal>active</literal> and <structfield>wait_event</structfield> is non-null, it
means that a query is being executed, but is being blocked somewhere
- in the system.+ in the system. To keep the reporting low-overhead, the system uses very lightweight+ synchronization. As a result, ephemeral discrepancies between the view's columns,+ for example between <structfield>wait_event</structfield> and+ <structfield>state</structfield>, or between <structfield>state</structfield> and+ <structfield>query_id</structfield>, are possible by nature.
</para>
</note>
--
2.41.0
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To: pgsql-hackers@postgresql.org
Cc: alexf01@gmail.com, samimseih@gmail.com, pgsql-hackers@lists.postgresql.org
Subject: Re: Doc: clarify possibility of ephemeral discrepancies between state and wait_event in pg_stat_activity
In-Reply-To: <ba25c8f6-eafa-4f6c-a436-5a0824bf9593@gmail.com>
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