topic Thread hangs during RuntimeService.startProcessInstanceByKey in Alfresco Archive

Thread hangs during RuntimeService.startProcessInstanceByKey

michalg — Mon, 13 Jan 2014 13:20:50 GMT

Hello,I would like ask about a problem with Activiti, which starts to be quite serious. But first some background:we are using Activiti as embedded Spring bean in our application. Application is deployed on several tomcat nodes.Engine itself has standard configuration, only jobExecutor lock has been

Re: Thread hangs during RuntimeService.startProcessInstanceByKey

frederikherema1 — Wed, 15 Jan 2014 08:36:59 GMT

What datasource are you using? If that are all the logs you get, it seems like it never gets any response from the "selectLatestProcessDefinitionByKey - ==> Preparing: select * from ACT_RE_PROCDEF where KEY_ = ? and VERSION_ = (select max(VERSION_)". Make sure you use a connection-pool that checks connections and evicts/recreates broken ones…

Do you have any details on the process-definition that is being used? Does it contain any asynchronous tasks or timers?
Also, does your activiti-engine use the job-executor a lot? In very high-load on the job-executor, the following condition can occur:

- All job-executor threads are occupied.
- The job-aquisition-thread looks for jobs to execute. In case the thread-pool is fully dried up, a special "strategy" is used to determine what to do with that job. The default (this is configurable) is that the calling thread runs the job instead. The calling thread, in this case, is the job-aquisition thread. This blocks any additional jobs from being executed as long as that job is being executed.
- When a new job is added (eg. using startProcessInstanceByKey), the job-executor is hinted at the end of the transaction commit. This hint will notify the aquisition-thread. if this is blocked, the current thread will wait for the aquisition-thread to complete. In case you have long-running jobs, this can cause a long wait-time. In case you have never-ending jobs (due to error), these jobs won't be retried because the thread that is responsible for actually re-running is occupied itself.

I'm suspecting the datasource is the culprit, just mentioning the job-executor scenario as additional info…

Re: Thread hangs during RuntimeService.startProcessInstanceByKey

michalg — Wed, 15 Jan 2014 11:13:23 GMT

We are using postgresql and pgpool. Used configuration should manage connections, but we have observed some problems with it and are working on configuration fixes. So if this is the case, that fix should also help with this problem.

There is no very high-load on the job-executor at the moment, so job executor scenario is less probable and first task in launched process is async, so execution should return immediately.

We will observe situation after modifying datasource configuration and confirm if that was the case.

Thank you for useful hints

Re: Thread hangs during RuntimeService.startProcessInstanceByKey

frederikherema1 — Wed, 15 Jan 2014 12:35:49 GMT

Great, keep us posted on the progress.

Re: Thread hangs during RuntimeService.startProcessInstanceByKey

elkammar — Mon, 28 Sep 2015 22:17:15 GMT

Hi frederikheremans,
I was wondering how to configure the default behavior of the calling thread running the job instead that you mentioned as configurable?