Re: postgresql shared buffers

From: Alvaro Herrera <alvherre(at)commandprompt(dot)com>
To: Praveen Kumar N <praveen_n(at)students(dot)iiit(dot)net>
Cc: Heikki Linnakangas <heikki(at)enterprisedb(dot)com>, pgsql-hackers(at)postgresql(dot)org
Subject: Re: postgresql shared buffers
Date: 2006-09-08 16:53:18
Message-ID: 20060908165318.GX5892@alvh.no-ip.org
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Praveen Kumar N wrote:
>
> one more doubt.in the following example we dont need sort right.But in
> this case also relations were scanned sequentially one by one.

In this case it's because the result from one seqscan was materialized.

> So is it the
> case that any relation is accessed only once from database while executing
> a given query?

Not in general -- you'll see that behavior only in particular cases.

--
Alvaro Herrera http://www.CommandPrompt.com/
The PostgreSQL Company - Command Prompt, Inc.

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