Date: Mon, 7 Jan 2019 08:13:32 -0600
From: Justin Pryzby <pryzby@telsasoft.com>
To: David Rowley <david.rowley@2ndquadrant.com>
Cc: Amit Langote <Langote_Amit_f8@lab.ntt.co.jp>,
	"Imai, Yoshikazu" <imai.yoshikazu@jp.fujitsu.com>,
	Alvaro Herrera <alvherre@2ndquadrant.com>,
	PostgreSQL-development <pgsql-hackers@postgresql.org>
Subject: Re: speeding up planning with partitions
Message-ID: <20190107141332.GT25379@telsasoft.com>
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On Mon, Jan 07, 2019 at 09:40:50PM +1300, 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.

The issue was this:
> > It turns out 1050 open()s are due to historic data which is no longer being
> > loaded and therefor never converted to relkind=p (but hasn't exceeded the
> > retention interval so not yet DROPped, either).

So there's no evidence of any issue with the patch.

Justin