Queries sometimes take 1000 times the normal time

Hello,

We're running a set of Half-Life based game servers that lookup user
privileges from a central PostgreSQL 7.3.4 database server (I recently
ported the MySQL code in Adminmod to PostgreSQL to be able to do this).

The data needed by the game servers are combined from several different
tables, so we have some views set up to provide the data in the format
needed.

Currently there's only a few users in the database for testing purposes,
and most of the time the user lookup's take 2-3 ms (I have syslog'ing of
queries and duration turned on), but several times per hour the duration
for one of the queries is 2-3 seconds (1000 times larger), while the
surrounding lookups take the usual 2-3 ms.

This is rather critical, as the game server software isn't asynchonous
and thus waits for a reply before continuing, so when someone connects,
and the user lookup happens to have one of these very long durations,
the players on this server experience a major lag spike, which isn't
very popular :-(

All the game servers and the database server are connected to the same
switch, so I don't think, that it is a network problem.

So far I've been unable to locate the problem, so any suggestions are
very welcome.

Regards,
Anders K. Pedersen