Message-ID: <7fd7f4eb1073884acfb673580f5ff589fcbf7abe.camel@cybertec.at>
Subject: Re: Forcing analyze on DB after upgrading?
From: Laurenz Albe <laurenz.albe@cybertec.at>
To: Wells Oliver <wells.oliver@gmail.com>, pgsql-admin
	 <pgsql-admin@postgresql.org>
Date: Wed, 30 Oct 2019 06:38:38 +0100
In-Reply-To: 
 <CAOC+FBUsOAKGBdNVmr2OSiRq7nLw=5jWMRjd9C5AWT6TVLXU-A@mail.gmail.com>
References: 
	<CAOC+FBUsOAKGBdNVmr2OSiRq7nLw=5jWMRjd9C5AWT6TVLXU-A@mail.gmail.com>
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On Tue, 2019-10-29 at 22:11 -0700, Wells Oliver wrote:
> I just upgraded from 9.6 to 12, and am noticing some queries are slow.
> 
> I did this kind of query:
> 
> SELECT relname, last_vacuum, last_autovacuum, last_analyze, last_autoanalyze
> FROM pg_stat_all_tables
> WHERE schemaname = 'myschema';
> 
> And noticed null values for everything, including last analyze date.
> 
> Does this mean the planner won't be able to optimize for these tables?
> Do I need to do something to prep my DB for planning after upgrade?

You used pg_upgrade, right?
pg_upgrade won't migrate any table statistics.

You'll have to run ANALYZE to collect new ones.

This is even mentioned in the output of pg_upgrade,
and it writes a convenient shell script that does the
ANALYZE for you.

Yours,
Laurenz Albe
-- 
Cybertec | https://www.cybertec-postgresql.com