Patch available at https://issues.apache.org/jira/browse/OFBIZ-10865
Reviews welcome, I probably won't have time to commit it for a few weeks so no rush. By the way I was amazed to notice that jobs are limited to 100 jobs per poll with a 30 second poll time, seems extremely conservative. They would have to be very slow jobs to not have the executor be idle most of the time. If no one objects I'd like to increase this to 2000 jobs with a 10 second poll time. Thanks Scott On Tue, 26 Feb 2019 at 09:13, Scott Gray <scott.g...@hotwaxsystems.com> wrote: > Hi Jacques, > > I'm working on implementing the priority queue approach at the moment for > a client. All things going well it will be in production in a couple of > weeks and I'll report back then with a patch. > > Regards > Scott > > On Tue, 26 Feb 2019 at 03:11, Jacques Le Roux < > jacques.le.r...@les7arts.com> wrote: > >> Hi, >> >> I put this comment there with OFBIZ-10002 trying to document why we have >> 5 as hardcoded value of /max-threads/ attribute in /thread-pool/ element >> (serviceengine.xml). At this moment Scott already mentioned[1]: >> >> /Honestly I think the topic is generic enough that OFBiz doesn't need >> to provide any information at all. Thread pool sizing is not exclusive to >> OFBiz and it would be strange for anyone to modify the numbers >> without first researching sources that provide far more detail than a few >> sentences >> in our config files will ever cover./ >> >> I agree with Scott and Jacopo that jobs are more likely IO rather than >> CPU bounded. So I agree that we should take that into account, change the >> current algorithm and remove this somehow misleading comment. Scott's >> suggestion in his 2nd email sounds good to me. So If I understood well we >> could >> use an unbounded but finally limited queue, like it was before. >> >> Although with all of that said, after a quick second look it appears >> that >> the current implementation doesn't try poll for more jobs than the >> configured limit (minus already queued jobs) so we might be fine with >> an >> unbounded queue implementation. We'd just need to alter the call to >> JobManager.poll(int limit) to not pass in >> executor.getQueue().remainingCapacity() and instead pass in something >> like >> (threadPool.getJobs() - executor.getQueue().size()) >> >> I'm fine with that as it would continue to prevent hitting physical >> limitations and can be tweaked by users as it's now. Note that it seems >> though >> uneasy to tweak as we received already several "complaints" about it. >> >> Now one of the advantage of a PriorityBlockingQueue is priority. And to >> take advantage of that we can't rely on "/natural ordering"/ and need to >> implement Comparable (which does no seem easy). Nicolas provided some >> leads below and this should be discussed. The must would be to have that >> parametrised, of course. >> >> My 2 cts >> // >> >> [1] https://markmail.org/message/ixzluzd44rgloa2j >> >> Jacques >> >> Le 06/02/2019 à 14:24, Nicolas Malin a écrit : >> > Hello Scott, >> > >> > On a customer project we use massively the job manager with an average >> of one hundred thousand job per days. >> > >> > We have different cases like, huge long jobs, async persistent job, >> fast regular job. The mainly problem that we detect has been (as you >> notified) >> > the long jobs that stuck poller's thread and when we restart OFBiz (we >> are on continuous delivery) we hadn't windows this without crash some jobs. >> > >> > To solve try with Gil to analyze if we can load some weighting on job >> definition to help the job manager on what jobs on the pending queue it can >> > push on queued queue. We changed own vision to create two pools, one >> for system maintenance and huge long jobs managed by two ofbiz instances >> and an >> > other to manage user activity jobs also managed by two instances. We >> also added on service definition an information to indicate the >> predilection pool >> > >> > This isn't a big deal and not resolve the stuck pool but all blocked >> jobs aren't vital for daily activity. >> > >> > For crashed job, we introduced in trunk service lock that we set before >> an update and wait a windows for the restart. >> > >> > At this time for all OOM detected we reanalyse the origin job and tried >> to decompose it by persistent async service to help loading repartition. >> > >> > If I had more time, I would be oriented job improvement to : >> > >> > * Define an execution plan rule to link services and poller without >> touch any service definition >> > >> > * Define configuration by instance for the job vacuum to refine by >> service volumetric >> > >> > This feedback is a little confused Scott, maybe you found interesting >> things >> > >> > Nicolas >> > >> > On 30/01/2019 20:47, Scott Gray wrote: >> >> Hi folks, >> >> >> >> Just jotting down some issues with the JobManager over noticed over the >> >> last few days: >> >> 1. min-threads in serviceengine.xml is never exceeded unless the job >> count >> >> in the queue exceeds 5000 (or whatever is configured). Is this not >> obvious >> >> to anyone else? I don't think this was the behavior prior to a >> refactoring >> >> a few years ago. >> >> 2. The advice on the number of threads to use doesn't seem good to me, >> it >> >> assumes your jobs are CPU bound when in my experience they are more >> likely >> >> to be I/O bound while making db or external API calls, sending emails >> etc. >> >> With the default setup, it only takes two long running jobs to >> effectively >> >> block the processing of any others until the queue hits 5000 and the >> other >> >> threads are finally opened up. If you're not quickly maxing out the >> queue >> >> then any other jobs are stuck until the slow jobs finally complete. >> >> 3. Purging old jobs doesn't seem to be well implemented to me, from >> what >> >> I've seen the system is only capable of clearing a few hundred per >> minute >> >> and if you've filled the queue with them then regular jobs have to >> queue >> >> behind them and can take many minutes to finally be executed. >> >> >> >> I'm wondering if anyone has experimented with reducing the queue the >> size? >> >> I'm considering reducing it to say 100 jobs per thread (along with >> >> increasing the thread count). In theory it would reduce the time real >> jobs >> >> have to sit behind PurgeJobs and would also open up additional threads >> for >> >> use earlier. >> >> >> >> Alternatively I've pondered trying a PriorityBlockingQueue for the job >> >> queue (unfortunately the implementation is unbounded though so it >> isn't a >> >> drop-in replacement) so that PurgeJobs always sit at the back of the >> >> queue. It might also allow prioritizing certain "user facing" jobs >> (such >> >> as asynchronous data imports) over lower priority less time critical >> jobs. >> >> Maybe another option (or in conjunction) is some sort of "swim-lane" >> >> queue/executor that allocates jobs to threads based on prior execution >> >> speed so that slow running jobs can never use up all threads and block >> >> faster jobs. >> >> >> >> Any thoughts/experiences you have to share would be appreciated. >> >> >> >> Thanks >> >> Scott >> >> >> > >> >
