Re: vacuum, dead rows, usual solutions didn't help

=?iso-8859-1?Q?G=E1bor?= Farkas <gabor@nekomancer.net> writes:
> basically, the problem is this part of the vacuum-output:

> INFO:  "sessions": found 2 removable, 6157654 nonremovable row versions
> in 478069 pages
> DETAIL:  6155746 dead row versions cannot be removed yet.

The problem is that you've got some old open transactions that could
potentially see those recently-dead rows, so VACUUM can't remove the
rows without breaking MVCC rules for those transactions.

Find the clients that are holding open transactions, and zap 'em.

> previously we were running this application with postgresql-7.4, and
> there the vacuuming worked fine. now we migrated this to
> postgresql-8.2.4, and it does not want to vacuum it properly.

I wonder whether you updated the client-side support libraries?

            regards, tom lane