Re: Why could different data in a table be processed with different performance?

Subject: Re: Why could different data in a table be processed with different performance?
From: Vladimir Ryabtsev <greatvovan@xxxxxxxxx>
Date: Fri, 28 Sep 2018 02:16:46 -0700
Cc: f.pardi@xxxxxxxxxxxx, pgsql-performance@xxxxxxxxxxxxxxxxxxxx
In-reply-to: <20180924233423.GV2471@telsasoft.com>
References: <CAMqTPq=aFwfiqv=P9EDs+UxeOgfe03kyQ0uvtUHvSxvfSvYR+w@mail.gmail.com> <4dbb8bea-bea3-74d8-a537-36bb9864cb9f@portavita.eu> <CAMqTPqkMDEkvx7jUquUCCkwgwYdcS-byzimjap2osxYWqp1KjA@mail.gmail.com> <e8d93055-9643-0ad2-d8bd-3f4fc344bf51@portavita.eu> <CAMqTPqnUB54YXQutPKPWdoUKEZOnV58WndfTvZagrNLiTr6RHw@mail.gmail.com> <20180924233423.GV2471@telsasoft.com>

> Does your LVM have readahead
> ramped up ? Try lvchange -r 65536 data/postgres (or similar).

Changed this from 256 to 65536.

If it is supposed to take effect immediately (no server reboot or other changes), then I've got no changes in performance. No at all.

Vlad

References:
- Why could different data in a table be processed with different performance?
  - From: Vladimir Ryabtsev
- Re: Why could different data in a table be processed with different performance?
  - From: Fabio Pardi
- Re: Why could different data in a table be processed with different performance?
  - From: Vladimir Ryabtsev
- Re: Why could different data in a table be processed with different performance?
  - From: Fabio Pardi
- Re: Why could different data in a table be processed with different performance?
  - From: Vladimir Ryabtsev
- Re: Why could different data in a table be processed with different performance?
  - From: Justin Pryzby