I'm kind of baffled by this, as I thought you had to flush the prepare out to a durable media, too. This is in fact, what http://activemq.apache.org/how-do-transactions-work.html claims happens. I don't see how XA transactions with the JDBCMessageStore is achieving the proper level of durability during the prepare stage. Hopfully one of the ActiveMQ developers can clear this up.
It looks like JDBCPersistenceAdapter's createQueueMessageStore(destination) method instantiates a new JDBCMessageStore called rc and then returns transactionStore.proxy(rc). The proxy method produces a MessageStore implementation by constructing an inner class based on a new ProxyMessageStore(messageStore), overriding addMessage and removeMessage to proxy through the original MemoryTransactionStore to the delegate messageStore, which is the JDBCMessageStore. The proxying happens by adding an AddMessageCommand or a RemoveMessageCommand inner class implementation to the Tx object (which is itself a static inner class of MessageTransactionStore). This Tx objects can be stored in either of two ConcurrentHashMaps called inflightTransactions and preparedTransactions. Calling prepare() on MemoryTransactionStore just shuffles the Tx from the former to the later and does not do anything else. In particular, it appears that the underlying JDBCMessageStore is not involved in the prepare step. During the commit, the XATransaction calls commit, which passes through to the transactionStore. In our case, MemoryTransactionStore gets and removes the Tx object from preparedTransactions (assuming two phase commit is on), and tx.commit() is called. The tx object executes the commands it added above, first iterating over all adds and then all removes. When these included JDBCMessageStore's addMessage or removeMessage, a JDBCAdapter is used to issue SQL to the database. The underlying jdbc connection commits when told to do so from the TransactionContext object, which commits when JDBCPersistenceAdapter's commitTransaction method is called. I don't quite see how this is connected to the XATransaction's calling of commit(). -- View this message in context: http://www.nabble.com/Only-memory-transaction-store-with-JDBC-persistence-adapter---tp18657395p18705185.html Sent from the ActiveMQ - User mailing list archive at Nabble.com.
