"dukehoops" wrote : I see. Makes sense. | | anonymous wrote : Can you comment more on why making the datasource READ_COMMITTED as well was necessary? | | I don't know - puzzled as well. But it absolutely was the case that my multithreaded load tests kept failing until I made that change, and haven't failed since. | | Most DBs substitute SERIALIZABLE with REPEATABLE_READ. So if you make your DS RR you have likely just moved to single threaded access. View the original post : http://www.jboss.org/index.html?module=bb&op=viewtopic&p=4218817#... Reply to the post : http://www.jboss.org/index.html?module=bb&op=posting&mode=reply&a...