Maurice de Chateau [http://community.jboss.org/people/MohReece] replied to the discussion "jBPM- Transaction isolation level" To view the discussion, visit: http://community.jboss.org/message/541577#541577 -------------------------------------------------------------- Hi Alexander, You're not mentioning which version of jBPM you're using, but in the user guide for version 3.2.x ( http://docs.jboss.com/jbpm/v3.2/userguide/html/persistence.html#isolation... http://docs.jboss.com/jbpm/v3.2/userguide/html/persistence.html#isolation...) you can read the following: "+Make sure that the database isolation level that you configure for  your        JDBC connection is at least READ_COMMITTED.+ +Almost all features run OK even with READ_UNCOMMITTED  (isolation level 0       and the only isolation level supported by HSQLDB).  But race  conditions might occur in the        job executor and with synchronizing multiple tokens.+" So that's quite clear in itself. But if you want a little more background, you can read this JIRA issue ( *https://jira.jboss.org/jira/browse/JBPM-983 JBPM-983*), in which Tom Baeyens explains about the underlying reasoning for this persistence aspect. Regards, Maurice -------------------------------------------------------------- Reply to this message by going to Community [http://community.jboss.org/message/541577#541577] Start a new discussion in jBPM at Community [http://community.jboss.org/choose-container!input.jspa?contentType=1&...]