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From: David Rowley <david.rowley@2ndquadrant.com>
Date: Wed, 15 May 2019 14:59:48 +1200
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Subject: Re: PostgreSQL 12: Feature Highlights
To: Amit Langote <Langote_Amit_f8@lab.ntt.co.jp>
Cc: "Jonathan S. Katz" <jkatz@postgresql.org>,
 pgsql-advocacy@lists.postgresql.org
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On Wed, 15 May 2019 at 14:31, Amit Langote
<Langote_Amit_f8@lab.ntt.co.jp> wrote:
>
> On 2019/05/15 11:03, Jonathan S. Katz wrote:
> > 2. Partitioning Improvements
> >
> > - Improved partition pruning, which improves performance on queries over
> > tables with thousands of partitions that only need to use a few partitions
> > - Improvements to COPY performance and ATTACH PARTITION
> > - Allow foreign keys to reference partitioned tables
>
> About the 1st item in "Partitioning Improvements", it's not just partition
> pruning that's gotten better.  How about writing as:
>
>  - Improved performance of processing tables with thousands of partitions
>    for operations that only need to touch a small number of partitions
>
> Per discussion upthread, that covers improvements to both partition
> pruning and tuple routing.

+1. Amit's words look fine to me.   I think if we're including this as
a headline feature then it should be to inform people that
partitioning is generally more useable with larger numbers of
partitions, not just that SELECT/UPDATE/DELETE now perform better when
pruning many partitions. The work done there and what's done to speed
up tuple routing in INSERT/COPY both complement each other, so they're
likely good to keep as one in the headline features list. Mentioning
one without the other might leave some people guessing about if we've
addressed the other deficiencies with partitioning performance.
Sadly, they can't refer to the release notes for more information
since they don't detail what's changed in this area :(

-- 
 David Rowley                   http://www.2ndQuadrant.com/
 PostgreSQL Development, 24x7 Support, Training & Services