Activiti deadlock occurs under JMeter performance test

Question

I have a problem with activiti concurrency. We have a wicket spring application with embedded activiti workflow engine. It works fine without concurrent users, but during jmeter performance test activiti creates deadlock on its own tables. For example: ACT_RU_JOB, ACT_RU_EXECUTION, ACT_RU_VARIABLE. I have found a topic on activiti forum about this problem ( Activiti Forum ). They suggest using queues to start activiti processes. This solution didn't solve the problem, because deadlocks still occuring. I provide some configuration and stacktrace for you. All answers can be useful for me. Thanks for the help!

my activiti configuration:

<bean id="processEngineConfiguration" class="org.activiti.spring.SpringProcessEngineConfiguration">
        <property name="databaseType" value="mssql" />
        <property name="dataSource" ref="dataSource" />
        <property name="transactionManager" ref="transactionManagerLugy" />
        <property name="databaseSchemaUpdate" value="true" />
        <property name="jobExecutorActivate" value="true" />
        <property name="deploymentResources" value="classpath*:/diagrams/idm/*.bpmn20.xml" />   
        <property name="history" value="none"/>     
        <property name="jdbcMaxActiveConnections" value="1000"/>
        <property name="jdbcMaxIdleConnections" value="10"/>
        <property name="jdbcMaxWaitTime" value="50000"/>
    </bean> 


    <bean id="processEngine" class="org.activiti.spring.ProcessEngineFactoryBean">
        <property name="processEngineConfiguration" ref="processEngineConfiguration" />
    </bean>

stacktrace:

### Error querying database.  Cause: org.hibernate.exception.LockAcquisitionException: Transaction (Process ID 67) was deadlocked on lock resources with another process and has been chosen as the deadlock victim. Rerun the transaction.
### The error may involve org.activiti.engine.impl.persistence.entity.VariableInstanceEntity.selectVariablesByExecutionId-Inline
### The error occurred while setting parameters
### Cause: org.hibernate.exception.LockAcquisitionException: Transaction (Process ID 67) was deadlocked on lock resources with another process and has been chosen as the deadlock victim. Rerun the transaction.
    at org.springframework.jms.listener.adapter.MessageListenerAdapter.invokeListenerMethod(MessageListenerAdapter.java:471)
    at org.springframework.jms.listener.adapter.MessageListenerAdapter.onMessage(MessageListenerAdapter.java:355)
    at org.springframework.jms.listener.AbstractMessageListenerContainer.doInvokeListener(AbstractMessageListenerContainer.java:535)
    at org.springframework.jms.listener.AbstractMessageListenerContainer.invokeListener(AbstractMessageListenerContainer.java:495)
    at org.springframework.jms.listener.AbstractMessageListenerContainer.doExecuteListener(AbstractMessageListenerContainer.java:467)
    at org.springframework.jms.listener.AbstractPollingMessageListenerContainer.doReceiveAndExecute(AbstractPollingMessageListenerContainer.java:325)
    at org.springframework.jms.listener.AbstractPollingMessageListenerContainer.receiveAndExecute(AbstractPollingMessageListenerContainer.java:263)
    at org.springframework.jms.listener.DefaultMessageListenerContainer$AsyncMessageListenerInvoker.invokeListener(DefaultMessageListenerContainer.java:1058)
    at org.springframework.jms.listener.DefaultMessageListenerContainer$AsyncMessageListenerInvoker.executeOngoingLoop(DefaultMessageListenerContainer.java:1050)
    at org.springframework.jms.listener.DefaultMessageListenerContainer$AsyncMessageListenerInvoker.run(DefaultMessageListenerContainer.java:947)
    at java.lang.Thread.run(Thread.java:662)

Answer 1

I removed all of the timers from my activiti diagram and deadlocks are disappeared. I don't know why, but it works.