Re: Vacuum statistics

Hi,

On Mon, May 12, 2025 at 5:30 AM Amit Kapila <amit(dot)kapila16(at)gmail(dot)com> wrote:
>
> On Fri, May 9, 2025 at 5:34 PM Alena Rybakina <a(dot)rybakina(at)postgrespro(dot)ru> wrote:
> >
> > I did a rebase and finished the part with storing statistics separately from the relation statistics - now it is possible to disable the collection of statistics for relationsh using gucs and
> > this allows us to solve the problem with the memory consumed.
> >
>
> I think this patch is trying to collect data similar to what we do for
> pg_stat_statements for SQL statements. So, can't we follow a similar
> idea such that these additional statistics will be collected once some
> external module like pg_stat_statements is enabled? That module should
> be responsible for accumulating and resetting the data, so we won't
> have this memory consumption issue.
>
> BTW, how will these new statistics be used to autotune a vacuum? And
> do we need all the statistics proposed by this patch?

Thanks for working on this. I agree with the general idea of having
minimal changes to the core. I think a simple approach would be to
have a hook in heap_vacuum_rel at the end, where vacuum stats are
prepared in a buffer for emitting LOG messages. External modules can
then handle storing, rotating, interpreting, aggregating (per
relation/per database), and exposing the stats to end-users via SQL.
The core can define a common data structure, fill it, and send it to
external modules. I haven't had a chance to read the whole thread or
review the patches; I'm sure this has been discussed.

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