Date: Thu, 13 Mar 2025 13:19:51 +0000
From: Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
To: Xuneng Zhou <xunengzhou@gmail.com>
Cc: PostgreSQL-development <pgsql-hackers@postgresql.org>
Subject: Re: Fwd: [BUG]: the walsender does not update its IO statistics
 until it exits
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Hi,

On Thu, Mar 13, 2025 at 07:35:24PM +0800, Xuneng Zhou wrote:
> Hi,
> Given that PGSTAT_MIN_INTERVAL is the go-to setting for stats flushes
>  * Unless called with 'force', pending stats updates are flushed happen once
>  * per PGSTAT_MIN_INTERVAL (1000ms). When not forced, stats flushes do not
>  * block on lock acquisition, except if stats updates have been pending for
>  * longer than PGSTAT_MAX_INTERVAL (60000ms).
>  *
>  * Whenever pending stats updates remain at the end of pgstat_report_stat()
> a
>  * suggested idle timeout is returned. Currently this is always
>  * PGSTAT_IDLE_INTERVAL (10000ms). Callers can use the returned time to set
> up
>  * a timeout after which to call pgstat_report_stat(true), but are not
>  * required to do so.
> 
>  I am curious about the reason for this:

Thanks for looking at it!

> > 1. maybe relying on PGSTAT_IDLE_INTERVAL would make more sense? In both
> > case
> > PGSTAT_MIN_INTERVAL or PGSTAT_MIN_INTERVAL, I'm not sure there is a need to
> > update the related doc.
> >
> >
> PGSTAT_IDLE_INTERVAL seems to reduce the frequency even more.

Yeah, I think that PGSTAT_MIN_INTERVAL is the one to use (that's why that's the 
one the patch is using). I just mentioned PGSTAT_IDLE_INTERVAL as an open door
for conversation in case one prefers a "larger" frequency. 

Regards,

-- 
Bertrand Drouvot
PostgreSQL Contributors Team
RDS Open Source Databases
Amazon Web Services: https://aws.amazon.com