Re: Controlling parallel queries

From: Kevin Loney <Kevin.Loney_at_astramerck.com>
Date: Fri, 18 Sep 1998 11:08:51 -0400
Message-ID: <uHuM1.3$8n3.18844@newsread.com>

Great questions, intriguing problem. You have a couple of options that I can see:

Use the parallel_min_percent parameter to force it to fail if not enough parallel servers are available.
Use the parallel_adaptive_multi_user init.ora parameter. I haven't tested this one out, the default is FALSE. Setting it to TRUE is supposed to "enable adaptive setting of degree for multiple user streams".

The only way you'll get the same performance every time is if you use the same degree
each time. Option 1 above will force the query to fail if it can't get the degree you need.
Option 2 should help prevent single users from using all your parallel_max_servers. 2 may
be your best bet, but I've never tried it, so ymmv. You've got an ideal test case for it, so
give it a try and let us know.

Kevin Loney
http://www.kevinloney.com Received on Fri Sep 18 1998 - 10:08:51 CDT