topic A dead lock occurred on ACT_HI_ACTINST in Alfresco Archive

A dead lock occurred on ACT_HI_ACTINST

william_thierry — Mon, 29 Aug 2016 15:51:39 GMT

Hello,We are currently facing deadlock on ACT_HI_ACTINST on full asynchronous/exclusive node processesorg.activiti.engine.impl.asyncexecutor.ExecuteAsyncRunnable Job 1169985 failedorg.apache.ibatis.exceptions.PersistenceException: ### Error querying database. Cause: com.microsoft.sqlserver.jdbc.SQL

Re: A dead lock occurred on ACT_HI_ACTINST

william_thierry — Mon, 29 Aug 2016 15:52:52 GMT

we are using actviti 5.20

Re: A dead lock occurred on ACT_HI_ACTINST

jbarrez — Thu, 01 Sep 2016 14:21:20 GMT

deadlocks can occur under very high loads, but very infrequent. What kind of load are we talking about.

Also worth mentioning: in the latest v6 beta3 we've been exactly working on the job executor to be way more performant than before. We also saw deadlocks under very high load. We've been able to improve on that greatly. Especially the new message based executor is much faster and can handle these things better than the one in 5.20 version.

Re: A dead lock occurred on ACT_HI_ACTINST

william_thierry — Thu, 01 Sep 2016 16:12:48 GMT

Thank you for your answer.

In order to have our REST API to being called twice which would cause unexpected behavior.
We Override Activiti DefaultFailedJobCommandFactory to modify Job retries policy to turn off every retries.

We are currently thinking about on SQL exceptions ( ibatis PersistenceException ) letting activiti engine handle the retry with JobRetryCmd , the other working solution is to change the activiti database isolation level to READ_COMMITTED_SNAPSHOT ( we are using SQL Server ).

But we are worried about unexpected behavior on activiti part if we change the isolation level.

And yes we are facing deadlocks only on heavy load.

Re: A dead lock occurred on ACT_HI_ACTINST

jbarrez — Fri, 02 Sep 2016 13:25:12 GMT

> But we are worried about unexpected behavior on activiti part if we change the isolation level.

Yeah, I would too. Activiti expects. READ_COMMITTED., so that's good. However, with SQL server I seem to recall not everything is 100% the same wrt isolation levels compared to other databases.

Re: A dead lock occurred on ACT_HI_ACTINST

william_thierry — Mon, 12 Sep 2016 06:32:41 GMT

Thank you for your answer, sorry i was away last week.

If I understood correctly we should stay on READ_COMMITTED and not READ_COMMITTED_SNAPSHOT ?

So our only option would be to let activi retry SQL Exceptions ?

Regards,