Re: Megabytes of stats saved after every connection

Phil Endecott <spam_from_postgresql_general@chezphil.org> writes:
> For some time I had been trying to work out why every connection to my
> database resulted in several megabytes of data being written to the
> disk, however trivial the query.  I think I've found the culprit:
> global/pgstat.stat.  This is with 7.4.7.

> This is for a web application which uses a new connection for each CGI
> request.  The server doesn't have a particularly high disk bandwidth and
> this mysterious activity had been the bottleneck for some time.  The
> system is a little unusual as one of the databases has tens of thousands
> of tables (though I saw these writes whichever database I connected to).

Well, there's the problem --- the stats subsystem is designed in a way
that makes it rewrite its entire stats collection on every update.
That's clearly not going to scale well to a large number of tables.
Offhand I don't see an easy solution ... Jan, any ideas?

> So can I expect this file to grow again?  I think I need the stats,
> though I'm not entirely sure about that.

If you're not using autovacuum then you don't need stats_row_level.

            regards, tom lane