Wolf-Dieter Fink [https://community.jboss.org/people/wdfink] created the discussion "Re: Data source transaction isolation level descriptions" To view the discussion, visit: https://community.jboss.org/message/738644#738644 -------------------------------------------------------------- Depends extreme on your requirements. A description of the levels can be found at http://en.wikipedia.org/wiki/Isolation_%28database_systems%29 wikipedia I think the most common is READ_COMMITED. If you don't want to overwrite changes you should use optimistic locking. SERIALIZABLE is the highest level and it will be slow down the access because there is no concurrent access. -------------------------------------------------------------- Reply to this message by going to Community [https://community.jboss.org/message/738644#738644] Start a new discussion in Datasource Configuration at Community [https://community.jboss.org/choose-container!input.jspa?contentType=1&...]