Skip to Main Content

Oracle Database Discussions

Announcement

For appeals, questions and feedback about Oracle Forums, please email oracle-forums-moderators_us@oracle.com. Technical questions should be asked in the appropriate category. Thank you!

Interested in getting your voice heard by members of the Developer Marketing team at Oracle? Check out this post for AppDev or this post for AI focus group information.

Auto DOP

LauryFeb 25 2015 — edited Feb 26 2015

Hi,

I have an Oracle11gR2 (11.2.0.4) database for which parallel_degree_policy  = limited.

I also have parallel_max_servers = 36, and parallel_degree_limit = 36.

At that stage, I would expect that with that parameter auto DOP be enabled and parallel queing being not enabled (that is what I can read from  the Oracle documentation).

Through the Cloud Control, I have sessions that are logged as a specific user, and all use a parallel degree of 12. This parallel degree is enforced by a trigger for ddl/dm/query, and for that specific user. If I count the number of parallel processes that are displayed (this is 12 for each session) I get a number that is higher than 36 (the value of parallel_max_servers).

Can someone explain me why it is so, and not limited to 36?

In one session, logged to a different user, I have parallel_degree_policy = auto, set at session level.

the query: select * from v$io_calibration_status returns a status "NOT AVAILABLE" which means that I/O calibration has not be done for that database. This is a necessary condition for using auto DOP. Yet, I observe, through the Cloud Control that that session is queued for parallel process.

Can someone explain me why is it so? I would expect that the query for this session be not queued.

Thanks by advance for any tips and explanation.

Groet, Laurent

Comments
Locked Post
New comments cannot be posted to this locked post.
Post Details
Locked on Mar 26 2015
Added on Feb 25 2015
23 comments
832 views