Hi I am new to Oracle Scheduler. My question is - Can we give both repeat interval and event condition in the Schedule object for a single job?
I have this requirement in job scheduling - A job should run at a scheduled time, but only if a certain event has occured.
For eg.
Job1 should run
- at 10 am every day
- but only if same job from yesterday is not running anymore. (This I gonna figure out based on the table entry.) So the event gonna be a cell entry say 'ENDED' in the table job_statuses.
Would be easier if I can give both info in the same job. Else another approach I gonna try is - Schedule the job based on time. If the earlier instance is still running , reschedule the job based on event. But this looks clumsy.
Thanks in advance.
Mayank
I'd encode the condition in the PL/SQL of the procedure itself. i.e. it runs at 10am every day, but the first thing it does is check if the previous job had finished successfully.
What you could do is create 3 jobs
EVENT_JOB
REPEAT_JOB
ACTUAL_WORK_JOB
EVENT_JOB and REPEAT_JOB just start ACTUAL_WORK_JOB. If that is already - or still - running, you get an error on which you can react accordingly.
Related
Env: Oracle 12c R2
Trying to understand what the best approach would be to set up an Oracle DBMS_SCHEDULER job that would be used to monitor a DBMS_ALERT trigger that checks when a specific column value changes within a table.
The thing is, this table column value change will sometimes occur on a frequent basis and sometimes it may only occur twice a day but I will need to monitor this column change via the DBMS_ALERT.
The trigger I have is as follows and I have a procedure called check_signal that checks for the signal that I wish to use within the DBMS_SCHEDULER job.
The goal that I am trying to achieve is that I am going to have the situation where I will need to run say, three jobs:
Job1
Job2
Job3
The thing is, the payload returned from Job1 is required and and passed as parameters into Job2 and again, the payload returned from Job2 is required and passed as parameters into Job3.
It is this wait/alert that I am trying to achieve through the use of DBMS_ALERTS.
create or replace trigger my_tab_upd after update of status on my_tab for each row
begin
dbms_alert.signal('mystatusalert', 'changed from '||:old.status||' to '||:new.status||'.');
end;
/
This will be used via a web-based application which is used by multiple users.
Just unsure on how to setup this scheduled job that will continuously check for the alert and then be used within the web app.
If there is a better means than DBMS_ALERT, then please let me know.
The general answer is simple, while polling for events every N seconds you get an average delay N/2 seconds and maximal delay of N seconds.
In context of DBMS_ALERT you should re-think this approach, as this will implement polling with wait on the event.
The periodically executed jobs make basically tho thinks:
DBMS_ALERT.REGISTER on an event name
wait with DBMS_ALERT.WAITONE
Assume that the DBMS_SCHEDULER jobs runs every 10 seconds and it is started in the phase with frequent signalling. So the first execution returns quickly after receiving an event.
The second execution falls in the quite period, so the job will wait hours to get an event.
I think this is not what you expect as
1) the waiting job will have an open session - what you want to avoid as follows from you other question
You may use timeout = 0 in the DBMS_ALERT.WAITONE, but this will return close to no events, except those fired accidentally between the REGISTER and WAITONE
2) if in the first 10 seconds two events are signalled, the second one will be lost as at the signaling time the subscribing job is not active and no registration exists.
I am trying to have scheduling in my spring boot application, I am already using scheduler with cron expression but the problem is that I have about five scheduler in which I need to schedule the first three scheduler tasks to run once in a day and the rest of which runs after executing these two tasks.
The problem is that when the first scheduler running for some time the second one scheduler starts when its time reaches and it makes misunderstandings because both tasks are using the same database as well as same table. I want to process a record only once e.g if any scheduler process a record will not be processed by any other scheduler that day. So now I want to schedule these tasks in a sequence when the first one completes the execution then the second one will be starts and so on.
I have an application where users can schedule to run reports at a certain time. The data for the reports is populated by an overnight batch process which might get delayed (occasionally) due to upstream issues. When that happens, the reports need to be re-tried every few minutes until we have data. I have a db table that records the status of the batch, there will be a row in that table when the data becomes available for this report.
I am thinking along these lines: When the data is not available, the task will cancel itself, but before it does that, it will dynamically schedule another copy of itself to execute every 5 mins. Once the data becomes available, the repeating task will run once and cancel all future runs.
Is this possible? Am I on the right track?
Any help is much appreciated.
Thanks.
Can you please help me with, what can be used to for scheduling an oozie coordinator job to execute on first Monday of every month.
I know we have a frequency parameter that can be set as ${coord:months(1)} . But this will not allow me to schedule the jobs on a particular day of a particular week of a month. Hope I am not complicating the question here.
Any help is strongly appreciated.
Thanks,
Syed
You unfortunately cannot schedule in the specific manner you are looking for. As you already note, you can run on a monthly basis - i.e. the 5th day of each month, but you are not be able to control the Day of the Week other than for the first materialization.
A possible work around this would be to run your coordinator on a weekly basis, to materialize on the Monday and then have a custom Java Action as your first step in the workflow that will throw an exception if it's not the first day of the month.
A downside of this approach is that you'll see 4 or so failures per month in the job list for the coordinator, but at least it will give you the behaviour you're looking for.
I learned (the hard way) that DDL statements cannot be executed in the non-transactional context of a logon trigger, and that the solution is a job. I want the job to be executed immediately and one single time and therefore set the next_date parameter to sysdate and the interval parameter to null.
Here is what I execute in the trigger:
dbms_job.submit(
job=>jobNumber,
what=>'someProcedure(someParameter);',
next_date=>sysdate,
interval=>null
);
This works quite good, but once the trigger has been fired (and the above command has been submitted) for the time, the audit log shows that the job keeps reappearing exactly every five seconds under the same user account it has been submitted under for the first time. The associated program is always something like ORACLE.EXE (J001), although it was of course a user session initiated from a client application.
Can anyone explain this to me please? I hoped to get a singular execution of the job and not an eternal recurrence. Thanks in advance!