From: | Murthy Nunna <mnunna(at)fnal(dot)gov> |
---|---|
To: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> |
Cc: | "pgsql-admin(at)postgresql(dot)org" <pgsql-admin(at)postgresql(dot)org> |
Subject: | RE: Query Performance after pg_restore |
Date: | 2023-12-24 17:00:20 |
Message-ID: | DM8PR09MB6677775D7847C1B00BE60E71B89AA@DM8PR09MB6677.namprd09.prod.outlook.com |
Views: | Raw Message | Whole Thread | Download mbox | Resend email |
Thread: | |
Lists: | pgsql-admin |
Thanks, Tom.
I am wondering if there is way to obtain same performance as before. Like restoring performance statistics?!
Simple analyze is not helping. And Vacuum is a overkill where there are no dead tuples.
I am not setting any hint bits... I can verify this in new and old if you can provide a query or some method to verify this... I still have original copy of same database on a different server for comparison.
-----Original Message-----
From: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
Sent: Sunday, December 24, 2023 10:12 AM
To: Murthy Nunna <mnunna(at)fnal(dot)gov>
Cc: pgsql-admin(at)postgresql(dot)org
Subject: Re: Query Performance after pg_restore
Murthy Nunna <mnunna(at)fnal(dot)gov> writes:
> I did pg_dump of a ~20TB database followed by pg_restore. I find simple queries like select count(*) running slow. I did a select count(*) on all tables before pg_dump which took ~4 hours. After pg_restore, same thing took 32 hours.
My bet is that that was setting commit hint bits, and hence incurring a lot of writes. If the data is reasonably stable that's a one-time expense.
regards, tom lane
From | Date | Subject | |
---|---|---|---|
Next Message | Ron Johnson | 2023-12-24 17:18:58 | Re: Query Performance after pg_restore |
Previous Message | Scott Ribe | 2023-12-24 16:27:28 | Re: Timestamps in outputs |