Insert speed

I have a user application use log.

Under pg 7.x the system performed fine.

In 8.1, the insert statements seem to take a long time sometimes, upto
several seconds or more.

Here is the table:
CREATE TABLE user_app_use_log
(
  user_id int4 NOT NULL,
  access_stamp timestamptz NOT NULL DEFAULT now(),
  app_name char(50) NOT NULL,
  url char(150) NOT NULL,
  form_params text,
  division_id char(3),
  url_params text,
  ip_address varchar(31)
)
WITHOUT OIDS;

There is no primary key, but the table is never updated, only inserted.
I removed the only index, with no improvement in performance (in case
the 8.2 "resolves index locking issues" was the concern for an 8.1 install.

Should I add a primary key column of serial?  Will that help?

If anyone has any ideas it would be appreciated.

--
Terry Fielder
terry@greatgulfhomes.com
Associate Director Software Development and Deployment
Great Gulf Homes / Ashton Woods Homes
Fax: (416) 441-9085