pg.ddx.io  pgsql-hackers@postgresql.org mailing list archive  

help / color / mirror / Atom feed
From: Amit Langote <Langote_Amit_f8@lab.ntt.co.jp>
To: David Rowley <david.rowley@2ndquadrant.com>
To: Justin Pryzby <pryzby@telsasoft.com>
Cc: Imai, Yoshikazu <imai.yoshikazu@jp.fujitsu.com>
Cc: Alvaro Herrera <alvherre@2ndquadrant.com>
Cc: PostgreSQL-development <pgsql-hackers@postgresql.org>
Subject: Re: speeding up planning with partitions
Date: Mon, 7 Jan 2019 18:17:07 +0900
Message-ID: <d724e640-c197-e89f-85ea-e8e11625c48e@lab.ntt.co.jp> (raw)
In-Reply-To: <CAKJS1f8fmcs2Smsm0K-2ZLZjv2GUs+qFZsaL2FmUi8Hed4dstw@mail.gmail.com>
References: <3be67028-a00a-502c-199a-da00eec8fb6e@lab.ntt.co.jp>
	<CAKJS1f8g9_BzE678BLBm-eoMMEYUUXhDABSpqtAHRUUTrm_vFA@mail.gmail.com>
	<a22f24d1-5e20-f352-f402-3101cb1213bd@lab.ntt.co.jp>
	<73596f90-023c-c358-be9a-3c21bffcb15d@lab.ntt.co.jp>
	<0F97FA9ABBDBE54F91744A9B37151A5122E7B1@g01jpexmbkw24>
	<08a6775f-7c88-81a8-8c2c-984d171b6db9@lab.ntt.co.jp>
	<0F97FA9ABBDBE54F91744A9B37151A51232FF7@g01jpexmbkw24>
	<0F97FA9ABBDBE54F91744A9B37151A5124C0A0@g01jpexmbkw24>
	<580ddb99-cd31-096d-d485-fc309d274498@lab.ntt.co.jp>
	<55bd88c6-f311-2791-0a36-11c693c69753@lab.ntt.co.jp>
	<20190103153900.GA6236@telsasoft.com>
	<CAKJS1f8fmcs2Smsm0K-2ZLZjv2GUs+qFZsaL2FmUi8Hed4dstw@mail.gmail.com>

Thanks Justin for reporting the results of your testing.

On 2019/01/07 17:40, David Rowley wrote:
> On Fri, 4 Jan 2019 at 04:39, Justin Pryzby <pryzby@telsasoft.com> wrote:
>> Running 11dev with your v10 patch applied, this takes 2244ms with empty buffer
>> cache after postmaster restarted on a totally untuned instance (and a new
>> backend, with no cached opened files).
>>
>> I was curious why it took even 2sec, and why it did so many opens() (but not
>> 20k of them that PG11 does):
> 
> It would be pretty hard to know that without seeing the query plan.

Yeah, I too would be curious to see if the resulting plan really needs to
do those open()s.  If all the open()s being seen here are accounted for by
un-pruned partitions (across the UNION ALL) contained in the plan and
their indexes, then the patch has done enough to help.  If the open()s can
be traced to pruned partitions, then there's something wrong with the patch.

Thanks,
Amit





view thread (265+ messages)  latest in thread

Message-ID: <d724e640-c197-e89f-85ea-e8e11625c48e@lab.ntt.co.jp>
Permalink:  ../d724e640-c197-e89f-85ea-e8e11625c48e@lab.ntt.co.jp/
Also on:    postgresql.org/message-id/d724e640-c197-e89f-85ea-e8e11625c48e@lab.ntt.co.jp

 · 

reply
Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Reply to all the recipients using the --to and --cc options:
  reply via email

  To: pgsql-hackers@postgresql.org
  Cc: Langote_Amit_f8@lab.ntt.co.jp, david.rowley@2ndquadrant.com, pryzby@telsasoft.com, imai.yoshikazu@jp.fujitsu.com, alvherre@2ndquadrant.com
  Subject: Re: speeding up planning with partitions
  In-Reply-To: <d724e640-c197-e89f-85ea-e8e11625c48e@lab.ntt.co.jp>

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

This inbox is served by DDX for PostgreSQL; see mirroring instructions
for how to clone and mirror all data and code used for this inbox