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Connor McDonald

Thanks for the question, Matthias.

Asked: May 20, 2020 - 11:23 am UTC

Answered by: Connor McDonald - Last updated: May 22, 2020 - 12:30 am UTC

Category: Database Administration - Version: 12.2

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You Asked

Solaris 11.4
Oracle 12.2

Hi,
we have about 70 Schedueler jobs defined, which are starting in intervalls from 1 minute to about 1 month.
Sometimes (about 2 to 3 times a weeks) there are time-windows of about 1 to 60 minutes , in which none of the jobs are starting.
It seams that the time of these windows not to correlate with the starting of one specific job.

We have controlled by a cron-job (schedueler wouldn't work) some of the resources. see below.
it seams None of values or rise or fall of these resources to correlate with the windows, when no job can be started by the scheduler.

Where should I look, to find the reason, that the scheduler jobs didn't start timely?

the query we used to find these windows:
select (ACTUAL_START_DATE-REQ_START_DATE),REQ_START_DATE,ACTUAL_START_DATE from dba_SCHEDULER_JOB_RUN_DETAILS
where
(job_name like 'xxxxx%' or job_name like 'xxxxxxxx%')
and (ACTUAL_START_DATE-REQ_START_DATE) > interval '30' second order by REQ_START_DATE desc;

the values, which we observe:
select sum(a.value) from v$sesstat a, v$statname b where a.statistic# = b.statistic# and b.name = 'opened cursors current';

select count(*) as "OPEN CURSORS" from v$open_cursor ;

select count(*) from v$process ;

select count(*) from v$session;

select count(*) from v$lock;

select count(*) from gv$transaction;


Kind regards
Matthias Penzlin



and we said...

A job won't start if a previous instance of that job is already running. More details here

https://connor-mcdonald.com/2019/03/26/long-running-scheduler-jobs/

If you are positive that this is not the case, then its time to talk to Support - they *have* been bugs in this area with various versions where the Scheduler gets into a state where it goes "dormant", in particular on Windows environments.

and you rated our response

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Reviews

Default maintenance window

May 26, 2020 - 9:04 am UTC

Reviewer: lh from finland

Hi

Are these windows of no jobs occuring when the default maintenance window is starting. I have seen such behavior. Size of the window varies quite a lot.

Non scientific test seemed to indicate that gaps got smaller when database was rebooted. They did not disapper.


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