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To: Florian Baumert <baumert@plt.de>
cc: pgsql-interfaces@postgreSQL.org
Subject: Re: [INTERFACES] Postgresql + lo 
In-reply-to: Your message of Fri, 9 Jul 1999 00:19:51 +0200
	<1913.990709@plt.de>
Date: Fri, 23 Jul 1999 09:57:30 -0400
Message-ID: <14398.932738250@sss.pgh.pa.us>
From: Tom Lane <tgl@sss.pgh.pa.us>

Florian Baumert <baumert@plt.de> writes:
> What happens is that it writes a -1 to the screen and a database-error
> "ERROR: lo_lseek: invalid large obj descriptor (0)"

You need "begin transaction"/"end transaction" around the use of the
LO handle (ie, surrounding lo_open ... lo_close).

The documentation has always stated that lo_open must be wrapped in
a transaction, but Postgres versions before 6.5 didn't enforce that
rule.  (Instead, they'd just fail occasionally if you broke it :-(.)

6.5 enforces the rule by auto-closing LO handles at transaction
commit --- which will be instantly upon completion of the lo_open
command, if you are not inside a transaction; so the first attempt
to do anything with the handle will draw "invalid large obj
descriptor".

This is definitely getting to be a FAQ...

			regards, tom lane