Re: how to calculate or know seq_scan scan how many blocks every time

From: Craig Ringer <ringerc(at)ringerc(dot)id(dot)au>
To: leo xu <leoxu8703(at)gmail(dot)com>
Cc: pgsql-general(at)postgresql(dot)org
Subject: Re: how to calculate or know seq_scan scan how many blocks every time
Date: 2012-07-27 00:40:43
Message-ID: 5011E38B.6000207@ringerc.id.au
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On 07/25/2012 07:38 PM, leo xu wrote:
> hello:
> i know oracle scatter read blocks,can set db_file_multiblock_read_count
> every time,
> i see postgres,it exists scatter read blocks,it is seq_scan,how to know
> scan many bloks every time?
>

If I understand correctly, you want to have a sequential scan read from
more than one place at once.

This is not currently supported.

The effective_io_concurrency setting would be where you would set it,
but it does not affect sequential scans at the moment.

--
Craig Ringer

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