Re: Inconsistency in reporting checkpointer stats - Mailing list pgsql-hackers

From Kyotaro Horiguchi
Subject Re: Inconsistency in reporting checkpointer stats
Date
Msg-id 20221222.113125.228690903229891782.horikyota.ntt@gmail.com
Whole thread Raw
In response to Re: Inconsistency in reporting checkpointer stats  (Bharath Rupireddy <bharath.rupireddyforpostgres@gmail.com>)
List pgsql-hackers
At Mon, 19 Dec 2022 18:05:38 +0530, Bharath Rupireddy <bharath.rupireddyforpostgres@gmail.com> wrote in 
> On Fri, Dec 16, 2022 at 2:14 PM Kyotaro Horiguchi
> <horikyota.ntt@gmail.com> wrote:
> >
> > In the first place I don't like that we count the same things twice.
> > Couldn't we count the number only by any one of them?
> >
> > If we remove CheckPointerStats.ckpt_bufs_written, CreateCheckPoint can
> > get the final number as the difference between the start-end values of
> > *the shared stats*. As long as a checkpoint runs on a single process,
> > trace info in BufferSync will work fine.  Assuming single process
> > checkpointing there must be no problem to do that. (Anyway the current
> > shared stats update for checkpointer is assuming single-process).
> 
> What if someone resets checkpointer shared stats with
> pg_stat_reset_shared()? In such a case, the checkpoint complete
> message will not have the stats, no?

I don't know. I don't believe the stats system doesn't follow such a
strict resetting policy.

regards.

-- 
Kyotaro Horiguchi
NTT Open Source Software Center



pgsql-hackers by date:

Previous
From: Michael Paquier
Date:
Subject: Re: Add LSN along with offset to error messages reported for WAL file read/write/validate header failures
Next
From: Richard Guo
Date:
Subject: Re: Optimization issue of branching UNION ALL