Re: BUG #16334: We recently upgraded PG version from 9.5 to 10.10 and system performance is not so good

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(dot)gc(at)decathlon(dot)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
/docs/current/pgupgrade.html?

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