Re: Query optimizing - paradox behave

Hallo!

Thanks a lot to You Tom. I stared only at the user and the system time.
I didn't found any C-function, with wich I could measure the whole time,
so I used getrusage(). I did not recognize, that the whole time is
reduced, because the User time is increased.
Could that anybody explain to me? Why is the usertime increased and the
whole time is decreased?
#
Anyway ..
Thanks all a lot for Your effort.
I will now tune my radiology-database further...

Thankful Greetings

David

"David M. Richter" <David(dot)M(dot)Richter(at)freenet(dot)de> writes:
> The query with the 3 tables is faster than the query with 2 tables.

How you figure that?

> time psql -d compare -c "SELECT patient.*,study.* FROM
> patient,study,relpatient_study000 r0 WHERE
> (patient.chiliOID=r0.parentOID AND study.chiliOID=r0.childOID) order by
> patient.name using <" > 3tableni
> 1.671u 0.130s 0:11.14 16.4% 0+0k 0+0io 208pf+0w

> time psql -d pacs -c "SELECT patient.*,study.* FROM patient,study WHERE
> (patient.chiliOID=study.patientOID ) order by patient.name using <" >
> 2tableni
> 1.730u 0.120s 0:09.44 19.5% 0+0k 0+0io 208pf+0w

9.44 vs 11.14 seconds looks like a clear advantage for the second query
to me...