[Haskell-cafe] strange performance issue with takusen 0.8.3

[Alistair Bayley]

2009/4/6 Marko Schütz <MarkoSchuetz at web.de>:
>
> I have an application where some simple data extracted from some
> source files is inserted into a PostgreSQL database. The application
> uses Takusen and is compiled with GHC 6.8.3. Some (59 in the test
> data) of the selects take on average 460ms each for a total time for
> this sample run of 30s. I prepare one select statement at the
> beginning of the run into which I then bind the specific values for
> every one of the selects. It does not seem to make a difference
> whether I do this or whether I just use a new statement for every
> select.
>
> For comparison, I have collected the SQL statements in a file with
> PREPARE ... and DEALLOCATE for _every_ select and then run this file
> through psql. This takes 2s!

Hello Marko,

I'm finding it hard to see what the problem is here. Is it that your
query takes 460ms, and you need it to be quicker? Or is it something
else? It would help to have some example code. Can you make a test
case which reproduces te problem, that you could share?


> For comparison, I have collected the SQL statements in a file with
> PREPARE ... and DEALLOCATE for _every_ select and then run this file
> through psql. This takes 2s!

If all you are doing is preparing and deallocating - i.e. not
executing - then that will be very quick, because the queries are
never executed.

Alistair