Subject: Re: PostgreSQL 12: Feature Highlights
References: <830415f7-78ec-ef7b-0f73-0e810ef87f91@postgresql.org>
 <f6225733-51c7-55a3-94fa-0a9f1d4a81eb@postgresql.org>
 <eab862c2-033f-56a8-198f-18427f599096@lab.ntt.co.jp>
 <CAKJS1f-pCFYGq1-go+ZyAR3GisQo-nTD=7E8ykk7Zqm9w+-OkA@mail.gmail.com>
 <e19c41f2-0c6a-dd0b-6289-4319005861b6@lab.ntt.co.jp>
 <20190516182628.kbkiajfnlooocgyg@momjian.us>
 <0cf10a27-c6a0-de4a-cd20-ab7493ea7422@lab.ntt.co.jp>
 <20190517153653.pmolnulev6imwsn3@momjian.us>
From: Amit Langote <Langote_Amit_f8@lab.ntt.co.jp>
Message-ID: <1edcf5e3-fca8-14d6-6c03-b57921c21cb8@lab.ntt.co.jp>
Date: Tue, 21 May 2019 09:47:54 +0900
User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:60.0) Gecko/20100101
 Thunderbird/60.6.1
MIME-Version: 1.0
In-Reply-To: <20190517153653.pmolnulev6imwsn3@momjian.us>
Content-Type: text/plain; charset=utf-8
Content-Language: en-US
Content-Transfer-Encoding: 7bit
To: Bruce Momjian <bruce@momjian.us>
Cc: David Rowley <david.rowley@2ndquadrant.com>,
        "Jonathan S. Katz" <jkatz@postgresql.org>,
        pgsql-advocacy@lists.postgresql.org
Precedence: bulk

On 2019/05/18 0:36, Bruce Momjian wrote:
> On Fri, May 17, 2019 at 07:56:55PM +0900, Amit Langote wrote:
>> I agree that the current description captures at a high level the many
>> changes that made it possible.  Although, a couple of commits listed with
>> this item don't have much to do with that description, AFAICT.  Especially
>> 959d00e9d [1], which taught the planner to leverage the ordering imposed
>> on partitions by range partitioning.  With that commit, getting ordered
>> output from partitioned tables is now much quicker, especially with a
>> LIMIT clause.  You can tell that it sounds clearly unrelated to the
>> description we have now, which is "processing thousands of partitions is
> 
> Yes, it does.  I added this text and moved the commit item:
> 
>         Avoid sorting when partitions are already being scanned in the
>         necessary order (David Rowley)

Thank you Bruce.

Regards,
Amit