http://www.adp-gmbh.ch/ora/misc/ext_table.html
Other than that, I have not found any advantage.
Jayadevan
From: Tom Lane <tgl@xxxxxxxxxxxxx>
To: Greg Smith <greg@xxxxxxxxxxxxxxx>
Cc: Craig Ringer <craig@xxxxxxxxxxxxxxxxxxxxx>, Amy Smith <vah123@xxxxxxxxx>, pgsql-general@xxxxxxxxxxxxxx
Date: 01/18/2010 08:25 PM
Subject: Re: postgres external table
Sent by: pgsql-general-owner@xxxxxxxxxxxxxx
Greg Smith <greg@xxxxxxxxxxxxxxx> writes:
> Craig Ringer wrote:
>> For those non-Oracle users among us, what's an external table?
> External tables let you map a text file directly to a table without
> explicitly loading it. In PostgreSQL, if you have data in a CSV file,
> usually you'd import it with COPY before you'd use it. If external
> tables were available, you'd just say there's an external table as a CSV
> file and you could start running queries against it.
I'm finding it hard to visualize a use-case for that. We must postulate
that the table is so big that you don't want to import it, and yet you
don't feel a need to have any index on it. Which among other things
implies that every query will seqscan the whole table. Where's the
savings?
regards, tom lane
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