Re: Odd blocking (or massively latent) issue - even with EXPLAIN

From: Jim Vanns <james(dot)vanns(at)framestore(dot)com>
To: Martin French <Martin(dot)French(at)romaxtech(dot)com>
Cc: Jim Vanns <james(dot)vanns(at)framestore(dot)com>, pgsql-performance(at)postgresql(dot)org, pgsql-performance-owner(at)postgresql(dot)org
Subject: Re: Odd blocking (or massively latent) issue - even with EXPLAIN
Date: 2012-07-24 09:34:11
Message-ID: 1343122451.12579.155.camel@sys367.ldn.framestore.com
Views: Raw Message | Whole Thread | Download mbox | Resend email
Thread:
Lists: pgsql-performance

> > That latter test - won't that pretty much just read from the page
> cache?
> > 'sync' may well have forced dirty pages to disk but does it actually
> > evict them to?
>
> Basically, the cache is avoided because of the size of the file.
> 6000000 blocks at 8k exceeds the size of RAM in the machine, so it
> *should* miss the cache and hit the disk directly. :)

Doh!

> >
> > Anyway, that is off topic... perhaps ;)
> >
> > Thanks again,
> >
> > Jim
> >
>
> Cheers
>
> Martin ============================================= Romax Technology
> Limited Rutherford House Nottingham Science & Technology Park
> Nottingham, NG7 2PZ England Telephone numbers: +44 (0)115 951 88 00
> (main) For other office locations see:
> http://www.romaxtech.com/Contact =================================
> =============== E-mail: info(at)romaxtech(dot)com Website: www.romaxtech.com
> ================================= ================ Confidentiality
> Statement This transmission is for the addressee only and contains
> information that is confidential and privileged. Unless you are the
> named addressee, or authorised to receive it on behalf of the
> addressee you may not copy or use it, or disclose it to anyone else.
> If you have received this transmission in error please delete from
> your system and contact the sender. Thank you for your cooperation.
> =================================================
>

--
Jim Vanns
Systems Programmer
Framestore

In response to

Browse pgsql-performance by date

  From Date Subject
Next Message Thomas Kellerer 2012-07-24 10:13:09 Using ctid column changes plan drastically
Previous Message Martin French 2012-07-24 09:18:53 Re: Odd blocking (or massively latent) issue - even with EXPLAIN