From: | Bertrand Drouvot <bertranddrouvot(dot)pg(at)gmail(dot)com> |
---|---|
To: | Michael Paquier <michael(at)paquier(dot)xyz> |
Cc: | pgsql-hackers(at)lists(dot)postgresql(dot)org |
Subject: | Re: per backend WAL statistics |
Date: | 2025-01-09 07:05:54 |
Message-ID: | Z391UplSgYDemTy+@ip-10-97-1-34.eu-west-3.compute.internal |
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Lists: | pgsql-hackers |
Hi,
On Thu, Jan 09, 2025 at 01:03:15PM +0900, Michael Paquier wrote:
> On Wed, Jan 08, 2025 at 11:11:59AM +0000, Bertrand Drouvot wrote:
> > Yeah, that's more elegant as it also means that the main callback will not change
> > (should we add even more stats in the future). Done that way in v2 attached.
>
> I've put my hands on v2-0002 to begin with something.
>
> +/* flag bits for different types of statistics to flush */
> +#define PGSTAT_FLUSH_IO (1 << 0) /* Flush I/O statistics */
> +#define PGSTAT_FLUSH_ALL (PGSTAT_FLUSH_IO)
>
> These are located and used only in pgstat_backend.c. It seems to me
> that we'd better declare them in pgstat_internal.h and extend the
> existing pgstat_flush_backend() with an argument so as callers can do
> what they want.
>
> + /* Get our own entry_ref if not provided */
> + if (!entry_ref)
> + entry_ref = pgstat_get_entry_ref(PGSTAT_KIND_BACKEND, InvalidOid,
> + MyProcNumber, false, NULL);
>
> This relates to the previous remark, actually, where I think that it
> is cleaner to have pgstat_flush_backend() do pgstat_get_entry_ref(),
> same way as HEAD, and just pass down the flags.
I see, so you keep pgstat_flush_backend() calls (with an extra arg) and remove
the new "pgstat_backend_flush_io()" function.
> This comes at the cost of pgstat_flush_backend_entry()
> requiring an extra pgstat_tracks_backend_bktype(), which is not a big
> issue, and the patch gets a bit shorter.
Yeah, all of the above is fine by me.
PFA v3 which is v2 refactoring with your proposed above changes.
Regards,
--
Bertrand Drouvot
PostgreSQL Contributors Team
RDS Open Source Databases
Amazon Web Services: https://aws.amazon.com
Attachment | Content-Type | Size |
---|---|---|
v3-0001-Extract-logic-filling-pg_stat_get_wal-s-tuple-int.patch | text/x-diff | 3.9 KB |
v3-0002-PGSTAT_KIND_BACKEND-code-refactoring.patch | text/x-diff | 9.7 KB |
v3-0003-per-backend-WAL-statistics.patch | text/x-diff | 22.0 KB |
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