Re: Running a query twice to ensure cached results.

From: "Luke Lonergan" <llonergan(at)greenplum(dot)com>
To: "Martijn van Oosterhout" <kleptog(at)svana(dot)org>
Cc: "Ron Mayer" <rm_pg(at)cheapcomplexdevices(dot)com>, pgsql-hackers(at)postgresql(dot)org
Subject: Re: Running a query twice to ensure cached results.
Date: 2006-06-13 12:46:23
Message-ID: C0B401AF.26FA2%llonergan@greenplum.com
Views: Raw Message | Whole Thread | Download mbox | Resend email
Thread:
Lists: pgsql-hackers

Martin,

On 6/13/06 5:42 AM, "Martijn van Oosterhout" <kleptog(at)svana(dot)org> wrote:

> Is it possible it may have something to do with the hint bits? There's
> are a bunch of bits in the header to deal with speeding up of MVCC
> tests. Maybe changing those bits marks the page dirty and forces a
> write?

Yes, that's it. Writing data twice (three times including WAL) is a Very
Bad Thing for large data work - how should we fix it?

- Luke

In response to

Responses

Browse pgsql-hackers by date

  From Date Subject
Next Message Martijn van Oosterhout 2006-06-13 12:52:27 Re: timezones to own config file
Previous Message Martijn van Oosterhout 2006-06-13 12:42:08 Re: Running a query twice to ensure cached results.