[Opensource] Re: Cron Jobs

[Michael Rimov]

At 12:14 AM 5/4/2003 -0500, you wrote:
>Mike, I found some thread-timing problems with using the JobHandlerControl 
>to 'restart' jobs.  I avoided this by simply requesting a 'stop' and then 
>modifying the JobQueue entry to enable the job for startup by setting: 
>StatusCode='A' and ServerID=0

That's what I've been doing too, actually.

>As far as server restart, I found that any job scheduled in the future 
>would have a StatusCode='R' (ie 'running' since it would have already been 
>processed by the controller) and that it would be picked up on server 
>restart for future launching.
>Not sure if I answered your question....

Yes it did.

>I had problems with 'recurring' 'multi-threaded' cron jobs.  If I recall 
>there was an anonymous inner class that would try to start() the thread on 
>the 2nd 'recurrence' of the job but Java raises an exception when 
>attempting this on a dead thread.  I believe the code was trapping that 
>exception and just ignoring it!  I made a weak attempt at fixing this by 
>creating new instances of the job/thread but ran into some problems so I 
>went with non-recurring multi-threaded jobs and had added multiple entries 
>in the JobQueue table.  If you go this route watch for the MaxJobs limit 
>because it counts jobs scheduled in the future as part of that limit!
>I believe I also tried the single-threaded recurring route but some 
>problems with poor thread-usage caused me to stick with the multi-threaded 
>non-recurring jobs.


Thanks for the info.  I haven't done any multithreaded jobs, since I too 
have been walking through the JobHandler to remove race 
conditions.  Between 5.0 and 5.0.4 I believe I've fixed about 5-6 issues, 
so you might want to give 5.0.4 a try to see if that takes care of things yet.

HTH, and thanks for the feedback!

                                         -Mike