Re: Question about DB VACUUM

Okay now I understand what is going on. I have a second thread which is
being used to read these objects out of the database to present to the
user, and because large objects can only be accessed in a transaction
mode I have not closed the transaction on this thread. Should I do a
commit or rollback to terminate the transaction, once I have closed the
large object, even though I have not done any modifications to the large
objects?

Chris

-----Original Message-----
From: Tom Lane [mailto:tgl(at)sss(dot)pgh(dot)pa(dot)us]
Sent: Monday, October 06, 2003 9:08 PM
To: cjwhite(at)cisco(dot)com
Cc: 'Robert Treat'; pgsql-admin(at)postgresql(dot)org
Subject: Re: [ADMIN] Question about DB VACUUM

"Chris White \(cjwhite\)" <cjwhite(at)cisco(dot)com> writes:
> But as you could see from the prior query \lo_list showed no large
> objects, this was done just prior to the vacuum.

> aesop=# \lo_list
> Large objects
> ID | Description
> ----+-------------
> (0 rows)

> aesop=# vacuum verbose pg_largeobject;
> NOTICE: --Relation pg_largeobject--
> NOTICE: Index pg_largeobject_loid_pn_index: Pages 2819; Tuples 460:
> Deleted 84.

This would seem to indicate that you have open transactions hanging
around somewhere in the background. VACUUM can't delete tuples that
might still be visible under MVCC rules to some open transaction.

regards, tom lane