Date: Thu, 2 Apr 2020 10:46:58 +0200
From: Julien Rouhaud <rjuju123@gmail.com>
To: tejaswini.gc@decathlon.com, pgsql-performance@postgresql.org
Subject: Re: BUG #16334: We recently upgraded PG version from 9.5 to 10.10
 and system performance is not so good
Message-ID: <20200402084658.GC64485@nol>
References: <16334-b99092d62b0bbb9a@postgresql.org>
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Hi,

On Thu, Apr 02, 2020 at 03:52:25AM +0000, PG Bug reporting form wrote:
> The following bug has been logged on the website:
> 
> Bug reference:      16334
> Logged by:          Tejaswini GC
> Email address:      tejaswini.gc@decathlon.com
> PostgreSQL version: 10.10
> Operating system:   Centos 7
> Description:        


First of all, this is not a bug.  You should have instead started a discussion
on pgsql-general or pgsql-performance.  I'm redirecting the discussion on
-performance.


> We have upgraded our database into version 10.10.


How did you upgrade?


> After upgrading we could see that the system performance is bad , and one of
> the applications linked to it via web service is not working.


Do you have any errors in the postgres logs?


> During this upgrade we have not done any code changes either on the
> application side or on our ERP side.
> 
> We are trying to debug everything from application perse, but till now we do
> not have any lead.
> 
> Can you tell us are there any measures that we need to take after upgrade.


It depends on how you did the upgrade.  If you used pg_upgrade, did you run the
generated script as documented in step 13 at
https://www.postgresql.org/docs/current/pgupgrade.html?

Otherwise, at least a database-wide VACUUM ANALYZE on every database is the
bare minimum to run after an upgrade.