Re: VACUUM FULL not working with persistent connections

On Thu, 24 Oct 2002, Juan Jose Comellas wrote:

> The problem is that Postgres seems to be making a logical delete for each row
> that is updated (i.e. it seems to be doing an INSERT followed by a DELETE),
> so a lot of cruft is created on the database. We need to avoid this because
> there are other processes that are permanently querying this table (normally
> needing a sequential scan over the table) and the performance of the queries
> gradually decreases with each update. We run a VACUUM ANALYZE every 30
> minutes on this table and with v7.1.3 the system performs acceptably. With
> v7.2 (we tried v7.2.1, v7.2.2 and v7.2.3) if we run a VACUUM FULL ANALYZE on
> the table almost none of the deleted rows are really vacuumed until the
> clients disconnect. When using the VERBOSE modifier, I noticed that sometimes
> some of the rows were effectively removed, but these we normally very few
> (less than 10%). We even tried a VACUUM FULL FREEZE ANALYZE without success.

Are the persistent connections staying idle in a transaction or outside of
one? If it were in one, I could see this, although I don't wee why it'd
be different from 7.1.x.