Re: [Proposal] Make the optimiser aware of partitions ordering

From: Julien Rouhaud <rjuju123(at)gmail(dot)com>
To: Ashutosh Bapat <ashutosh(dot)bapat(at)enterprisedb(dot)com>
Cc: Peter Eisentraut <peter(dot)eisentraut(at)2ndquadrant(dot)com>, Robert Haas <robertmhaas(at)gmail(dot)com>, pgsql-hackers Hackers <pgsql-hackers(at)postgresql(dot)org>
Subject: Re: [Proposal] Make the optimiser aware of partitions ordering
Date: 2017-09-22 19:34:11
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On Thu, Sep 21, 2017 at 11:13 AM, Julien Rouhaud <rjuju123(at)gmail(dot)com> wrote:
> On Thu, Sep 21, 2017 at 10:52 AM, Ashutosh Bapat
> <ashutosh(dot)bapat(at)enterprisedb(dot)com> wrote:
>> With 9140cf8269b0c4ae002b2748d93979d535891311, we store the
>> RelOptInfos of partitions in the RelOptInfo of partitioned table. For
>> range partitioned table without default partition, they are arranged
>> in the ascending order of partition bounds. This patch may avoid
>> MergeAppend if the sort keys match partition keys by creating an
>> Append path by picking sorted paths from partition RelOptInfos in
>> order. You may use slightly modified version of
>> add_paths_to_append_rel().
> Yes, I just saw this commit this morning, and this is exactly what I
> was missing, thanks for the pointer and the patch!

PFA v3 of the patch, once again rebased and that now use all the newly
available infrastructure.

I also added a check that a sorted append can't be generated when a
default partition has been declared.

Attachment Content-Type Size
sorted_append_v3.diff text/plain 44.6 KB

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