Re: send()/receive() and on-disk storage - Mailing list pgsql-hackers

From Martijn van Oosterhout
Subject Re: send()/receive() and on-disk storage
Date
Msg-id 20060929135156.GE8702@svana.org
Whole thread Raw
In response to send()/receive() and on-disk storage  (Markus Schaber <schabi@logix-tt.com>)
Responses Re: send()/receive() and on-disk storage  (Markus Schaber <schabi@logix-tt.com>)
List 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@svana.org>   http://svana.org/kleptog/
> From each according to his ability. To each according to his ability to litigate.

pgsql-hackers by date:

Previous
From: Markus Schaber
Date:
Subject: send()/receive() and on-disk storage
Next
From: Heikki Linnakangas
Date:
Subject: Re: Block B-Tree concept