If you want to speed up the elapsed times, then the first thing would be
to attempt to reduce the IO using some indexes, e.g. on test1(anumber),
test2(anumber), test3((anumber%13)), test3((anumber%5)) and
test4((anumber%27))
However if you wish to keep hammering the IO then the you would not use
any indexes. However elapsed times for operations like:
CREATE TABLE test4 AS SELECT ... FROM test1 JOIN test2 ON
test1.anumber=test2.anumber;
are going to increase non linearly with the size of the source table
test1 (unless there are indexes on the anumber columns).
I think this particular test is designed as a testbed for measuring IO
performance - as opposed to Postgresql performance.
regards
Mark
nbarraza@uolsinectis.com.ar wrote:
>Hi everyone,
>I found that performance get worse as the size of a given table
>increases. I mean, for example I´ve just run some scripts shown in
>
>http://www.potentialtech.com/wmoran/postgresql.php
>
>I understand that those scripts are designed to see the behavior of postgresql under different filesystems. However,
sincethem generate
>a lot of I/O activity, I think they can be used to adjust some
>configuration parameters. In that way, I increased the number of tuples inserted in the initial table to 2000000 and
3000000.What
>I saw is that the running time goes from 3 min., to 11 min. My question is, is it possible to use that test to tune
>some parameters?, if the answer is yes, what parameters should I change to get shorter running times?
>
>
>
>