Horton

Re: [HACKERS] advanced partition matching algorithm for partition-wise join

Ashutosh Bapat <ashutosh.bapat.oss@gmail.com>

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From: Ashutosh Bapat <ashutosh.bapat.oss@gmail.com>
To: Etsuro Fujita <etsuro.fujita@gmail.com>
Cc: Tom Lane <tgl@sss.pgh.pa.us>, Kuntal Ghosh <kuntalghosh.2007@gmail.com>, Ashutosh Bapat <ashutosh.bapat@2ndquadrant.com>, Tomas Vondra <tomas.vondra@2ndquadrant.com>, Mark Dilger <mark.dilger@enterprisedb.com>, amul sul <sulamul@gmail.com>, Robert Haas <robertmhaas@gmail.com>, Thomas Munro <thomas.munro@gmail.com>, Amit Langote <Langote_Amit_f8@lab.ntt.co.jp>, Rajkumar Raghuwanshi <rajkumar.raghuwanshi@enterprisedb.com>, Etsuro Fujita <fujita.etsuro@lab.ntt.co.jp>, Dmitry Dolgov <9erthalion6@gmail.com>, Antonin Houska <ah@cybertec.at>, PostgreSQL-development <pgsql-hackers@postgresql.org>
Date: 2020-04-09T14:04:01Z
Lists: pgsql-hackers

Commits

Same data as JSON: GET /api/v1/messages/:b64id/commits the thread's linked commits as JSON, with link sources. API reference →

  1. Suppress unused-variable warning.

  2. Allow partitionwise joins in more cases.

  3. Avoid crash in partitionwise join planning under GEQO.

  4. Disable support for partitionwise joins in problematic cases.

  5. Add plan_cache_mode setting

  6. Add test for partitionwise join involving default partition.

  7. Revise API for partition_rbound_cmp/partition_rbound_datum_cmp.

On Thu, Apr 9, 2020 at 12:03 PM Etsuro Fujita <etsuro.fujita@gmail.com> wrote:
>
> On Thu, Apr 9, 2020 at 2:36 PM Tom Lane <tgl@sss.pgh.pa.us> wrote:
> > Etsuro Fujita <etsuro.fujita@gmail.com> writes:
> > > Yeah, partition_bounds_merge() is currently called only from
> > > try_partitionwise_join(), which guarantees that the strategies are the
> > > same.
>
> > If there's only one caller and there's not likely to ever be more,
> > then I tend to agree that you don't need the assertion.
>
> It seems unlikely that partition_bounds_merge() will be called from
> more places in the foreseeable future, so I'd still vote for removing
> the assertion.

When I wrote that function, I had UNION also in mind. A UNION across
multiple partitioned relations will be partitioned if we can merge the
partition bounds in a sensible manner. Of course the current structure
of that function looks more purposed for join, but it's not difficult
to convert it to be used for UNION as well. In that case those set of
functions will have many more callers. So, I will vote to keep that
assertion now that we have it there.
-- 
Best Wishes,
Ashutosh Bapat