grinding to a halt?

We are running a web/db site with PostgreSQL 6.5.2 under FreeBSD 3.3-STABLE
(other components of the system are Apache 1.3.9 and PHP 3.0.12).  We are
trying to load in content via the web application, which involves a lot of db
selects, inserts, and updates, and find that the db grinds to a halt.  I can
see a bunch of postgres processes chewing system resources, but the web pages
never return.  Apache and the OS itself seem to be ok, just slow, but Postgres
is not responding.

The system in its current prototype state does not make use of transactions;
inserts into the database just occur as raw inserts.  Could this be the cause
of my problem?  Or is there some fundamental thing I need to do in setting up
Postgres so that it works efficiently?

I assume I have simply overlooked something obvious, because the db appears to
be unusuable and I know that is not the case.

What other information about my setup would help to debug my problem?

Thanks.

Charles

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