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Re: send()/receive() and on-disk storage

From: Martijn van Oosterhout <kleptog(at)svana(dot)org>
To: Markus Schaber <schabi(at)logix-tt(dot)com>
Cc: PostgreSQL-development <pgsql-hackers(at)postgresql(dot)org>
Subject: Re: send()/receive() and on-disk storage
Date: 2006-09-29 13:51:56
Message-ID: 20060929135156.GE8702@svana.org (view raw or flat)
Thread:
Lists: pgsql-hackers
On Fri, Sep 29, 2006 at 03:44:07PM +0200, Markus Schaber wrote:
> Does PostgreSQL call the datatypes' defined send() function before
> storing the tuple data in the table, on disk, and call receive() when
> reading it again?

No.

> My position was that send()/receive() are only used for client
> communication in the V3 protocol binary mode, and COPY in binary mode,
> but the backend stores them in the tables as_is (modulo compression/
> TOASTing).

Yes.

It would be terribly inefficient to call those functions for each
read/write. The disk has the internal format, send/receive deal with a
portable not-host-dependant representation of the data.

Have a nice day,
-- 
Martijn van Oosterhout   <kleptog(at)svana(dot)org>   http://svana.org/kleptog/
> From each according to his ability. To each according to his ability to litigate.

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