Re: Assessing performance of fetches

John Rouillard <rouilj(at)renesys(dot)com> writes:
> I am seeing:

> 2011-04-16 00:55:33 UTC user(at)database(3516): LOG: duration:
> 371954.811 ms statement: FETCH FORWARD 1 FROM c_2aaaaaaeea50_a08

> While I obviously have a problem here, is there any way to log the
> actual select associated with the cursor other than logging all
> statements?

Can't think of one :-(

> Also once I have the select statement, does the fact that is is
> associated with a fetch/cursor change the steps I should take in
> tuning it compared to somebody just issuing a normal select?

The planner does treat cursor queries a bit different from plain
queries, putting more emphasis on getting the first rows sooner.
If you want to be sure you're getting the truth about what's happening,
try
EXPLAIN [ANALYZE] DECLARE c CURSOR FOR SELECT ...
rather than just
EXPLAIN [ANALYZE] SELECT ...
Other than that, it's the same as tuning a regular query.

regards, tom lane