Re: Parallel heap vacuum

On Sun, Jan 19, 2025 at 7:50 AM Tomas Vondra <tomas@vondra.me> wrote:
>
> Hi,
>
> Thanks for the new patches. I've repeated my benchmarking on v8, and I
> agree this looks fine - the speedups are reasonable and match what I'd
> expect on this hardware. I don't see any suspicious results like with
> the earlier patches, where it got much faster thanks to the absence of
> SKIP_PAGE_THRESHOLD logic.
>
> Attached is the benchmarking script, CSV with raw results, and then also
> two PDF reports comparing visualizing the impact of the patch by
> comparing it to current master.
>
> * parallel-vacuum-duration.pdf - Duration of the vacuum, and duration
> relative to master (green - faster, read - slower). The patch is clearly
> an improvement, with speedup up to ~3x depending on the index count and
> a fraction of updated rows.
>
> * parallel-vacuum-reads.pdf - Average read speed, as reported by VACUUM
> VERBOSE. With the patch it can reach up to ~3GB/s, which is about the
> max value possible on this hardware - so that's nice. I'll try to test
> this on a better storage, to see how far it can go.

Thank you for doing a performance benchmark. These results make sense to me.

> I haven't done any actual code review on the new patches, I'll try to
> find time for that sometime next week.

Thank you!

Regards,

--
Masahiko Sawada
Amazon Web Services: https://aws.amazon.com