Poor Oracle8 performance on NT without adjustment of priorites

I have a lot of experience with Oracle on other operating systems but not too much with NT so please excuse me if this is a stupid question.

We have a set of queries that run great on Oracle8 on UNIX but when we run them on a PC with NT server with SP5 they run like dogs. We moved the same database to SQL Server on the same PC and they run great.

We tried to trouble shoot things using Oracle tuning methodologies and got nowhere. There was no evident bottleneck.

So we tried changing the Oracle process's priority from Normal to Real-time using Task Manager and we got the performance we wanted. The set of queries ran in essentially the same with Oracle as they did with SQL Server.

In all of these tests the server was completely idle except for running this stream of queries. Elapsed time dropped from 8 seconds (normal priority) to .8 seconds (real-time).

So my questions are these:

What is the NT scheduler doing with the CPU when Oracle has Normal priority? There aren't any other ready processes to run.

Do processes with real-time priority take a different path through the scheduler?

If a process changes from a waiting state (i.e., blocked on IO) to a ready state, how long does it take NT to recognize this and dispatch the process? Is this interval dependent on the processes priority? Is this interval tunable?

TIA, Josh Received on Thu Jul 06 2000 - 00:00:00 CDT