Two situations: 1. Whenever a cache method that is called within the scope of a transaction throws an exception the transaction it is marked for rollback (InvocationContextInterceptor.markTxForRollbackAndRethrow) 2. A node leaves and there is a transaction on another node that has locked acquired on the node that leaves the cluster. In this situation the transaction will fail during the commit phase (StaleTransactionCleanup.onViewChange). Cheers, Mircea On 8 Dec 2010, at 15:31, Vladimir Blagojevic wrote: