Terry Fielder <terry@ashtonwoodshomes.com> writes:
> Under pg 7.x the system performed fine.
> In 8.1.9, the insert statements seem to take a long time sometimes, upto
> several seconds or more.
> 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.
Hmm. With no indexes, inserts ought to be basically a constant-time
operation. I suspect what you are looking at is stalls caused by
checkpoints or other competing disk activity. I'd suggest watching the
output of "vmstat 1" or local equivalent, and seeing if you can
correlate the slow inserts with bursts of disk activity.
Have you tuned the 8.1 installation? I'm wondering about things like
checkpoint_segments and wal_buffers maybe being set lower than you had
them in 7.4.
regards, tom lane