Re: job_priority for Oracle scheduler jobs

Thanks Mark B

I owe you a beer :-)

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On Fri, May 26, 2023 at 10:13 AM Mark Burgess < mark_at_burgess-consulting.com.au> wrote:

> Hi Fairlie,
>
> We have one customer using job priority in prod with all jobs run under
> resource manager groups (to limit session concurrency for different job
> classes).
>
> This was working well on 11gR2 - jobs assigned different priorities ran in
> the correct order based on priority within the resource group - has been
> problematic since upgrading to 19.15 (still yet to get to a more current
> RU). Basically the job priority is ignored if the jobs are run under a
> resource consumer group. I am not sure if this is the case for jobs run
> outside of a resource consumer group.
>
> Overall there seem to be some fundamental changes to the way the DBMS
> scheduler works under the covers in 19c compared to 11gR2. Not unexpected,
> and probably for the better, but seeing some of the issues around the
> scheduler that have come out of this customer since upgrading I would
> definitely be erring on the side of caution and test the daylights out of
> any changes around job priority and scheduling. Particularly if you have a
> high number of jobs going through the scheduler.
>
> Regards,
>
> Mark
> On 26 May 2023 at 8:41 AM +1000, Fairlie Rego <fairlie.rego_at_gmail.com>,
> wrote:
>
> Thanks Mark for your reply
> I am aware of this
> However the question was more to do with
> if anyone is using this in production in anger
> Apologies for not being clear on the previous email
>
> Cheers
> Fairlie
>
> Sent from my iPhone
>
> On 26 May 2023, at 4:01 am, Powell, Mark <mark.powell2_at_dxc.com> wrote:
>
> 
>
> You use the set_attribute procedure to set the job_priority which defaults
> to 3 out of 1 to 5 with 1 being highest.
>
> DBMS_SCHEDULER (oracle.com)
> <https://docs.oracle.com/en/database/oracle/oracle-database/19/arpls/DBMS_SCHEDULER.html#GUID-D7A11F8A-8746-4815-91C4-BC8DDBA4C74A>
> PL/SQL Packages and Types Reference
> <https://docs.oracle.com/en/database/oracle/oracle-database/19/arpls/DBMS_SCHEDULER.html#GUID-D7A11F8A-8746-4815-91C4-BC8DDBA4C74A>
> The DBMS_SCHEDULER package provides a collection of scheduling functions
> and procedures that can be called from any PL/SQL program.
> docs.oracle.com
>
>
> Mark Powell
> Database Administration
> (313) 592-5148
>
>
> ------------------------------
> *From:* oracle-l-bounce_at_freelists.org <oracle-l-bounce_at_freelists.org> on
> behalf of Fairlie Rego <fairlie.rego_at_gmail.com>
> *Sent:* Thursday, May 25, 2023 5:23 AM
> *To:* ORACLE-L <oracle-l_at_freelists.org>
> *Subject:* job_priority for Oracle scheduler jobs
>
> Hi all,
>
> I am currently working on a system which is a heavy user of Oracle
> scheduler jobs. During certain hours we have almost 20,000 jobs running in
> an hour
> and some critical ones do not seem to get kicked off at the exact time
> they need to run.
>
> Is anyone using the job_priority feature and if so in what version and
> have they faced any issues with it.?
>
> *"When several jobs within the same job class are scheduled to start at
> the same time, the job coordinator uses the job priority to decide which
> job to execute first."*
>
> <image.png>
>
>
> Cheers
> Fairlie
>
>
>

-- 
Fairlie Rego
Executive Database Architect
www.technoconsulting.com.au
http://www.linkedin.com/in/fairlierego
https://fairlierego.wordpress.com/

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