Re: Postgres 11 release notes

On Mon, May 21, 2018 at 07:34:18PM +1200, David Rowley wrote:
> On 19 May 2018 at 03:58, Amit Langote <amitlangote09(at)gmail(dot)com> wrote:
> > I wonder what you think about including this little performance item:
> >
> > https://www.postgresql.org/message-id/E1eotSQ-0005V0-LV@gemulon.postgresql.org
> >
> > especially considering the part of the commit message which states
> >
> > ...Still, testing shows
> > that this makes single-row inserts significantly faster on a table
> > with many partitions without harming the bulk-insert case.
> >
> > I recall seeing those inserts being as much as 2x faster as partition
> > count grows beyond hundreds. One might argue that we should think
> > about publicizing this only after we've dealt with the
> > lock-all-partitions issue that's also mentioned in the commit message
> > which is still a significant portion of the time spent and I'm totally
> > fine with that.
>
> While I do think that was a good change, I do think there's much still
> left to do to speed up usage of partitioned tables with many
> partitions.
>
> I've been working a bit in this area over the past few weeks and with
> PG11 I measured a single INSERT into a 10k RANGE partitioned table at
> just 84 tps (!), while inserting the same row into a non-partitioned
> table was about 11.1k tps. I have patches locally that take this up to
> ~9.8k tps, which I'll submit for PG12. I'm unsure if we should be

Yikes! I think the question is whether we need to _remove_ the item I
just posted that is already in the release notes:

Allow faster partition elimination during query processing (Amit
Langote, David Rowley, Dilip Kumar)

This speeds access to partitioned tables with many partitions.

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Bruce Momjian <bruce(at)momjian(dot)us> http://momjian.us
EnterpriseDB http://enterprisedb.com

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