From: Qingqing Zhou <zhouqq@cs.toronto.edu>
To: pgsql-performance@postgresql.org
Subject: Re: Variation between query runtimes
Date: Mon, 12 Jun 2006 10:50:28 +0800
Message-ID: <e6ikpj$1mo4$1@news.hub.org> (raw)
References: <5809b390606102335j41f734d8j@mail.gmail.com>
""John Top-k apad"" <topkapad@gmail.com> wrote
>
> from pg_stast_get_blocks_fetched i can see that both queries need almost
the
> same number of disk fetches which is quite reasonable ( the index is
> unclustered).
>
> But as you can see there is a great variation between query
> runtimes.Cansomeone explain this differnce?
>
Can you give a self-contained example (including what you did to clear the
file system cache (maybe unmount?) to *not* let the 2nd query to use the
file content from the 1st query)?
Regards,
Qingqing
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Reply to all the recipients using the --to and --cc options:
reply via email
To: pgsql-performance@postgresql.org
Cc: zhouqq@cs.toronto.edu
Subject: Re: Variation between query runtimes
In-Reply-To: <e6ikpj$1mo4$1@news.hub.org>
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
This inbox is served by DDX for PostgreSQL; see mirroring instructions
for how to clone and mirror all data and code used for this inbox