[ http://issues.apache.org/jira/browse/DAYTRADER-22?page=comments#action_12449715 ] Christopher James Blythe commented on DAYTRADER-22: ---------------------------------------------------
All... Since my involvement with Daytrader (and Trade), we've never been all that concerned with the Async 1-phase mode. Here is the lay of the land to my understanding... Sync mode - Uses JMS topics and TradeTopicMDB to publish changes to the quote prices - There is flag in the DDs to disable this but it doesn't seem to apply to direct mode (only EJB mode) Async 2-phase mode - This mode uses a JMS queue and the TradeBroker to handle order processing - Specifically, the buy and sell operations call a queueOrder method to place a message on the queue - The queueOrder is part of an XA transaction because two resource managers (JMS and database) are involved to create the order in the databse and place a message on the queue - The MDB starts a new transaction when the message is read from the queue. The MDB then executes the completeOrder method which updates the order in the database inside the original MDB transaction context Async 1-phase mode - Does the same as above, but does not involve an UserTransaction to provide XA - Since the MDB is container-managed, TradeEJB is used to complete the order and create a new transaction (avoiding XA) My guess is that the Async 1-phase mode was added to messure the overhead associated with handling the XA transaction. I think Andrew Spyker was partly responsible for adding this... so, let me see if I can track him down to get more details. Regardless, I have never found that much value in Async 1-phase mode. If you are using two different resources as part of a logical transaction, you should always use XA to ensure proper rollback handling. Honestly, I see very little need to keep it around... However, there might be some possiblities I have not considered. Removing this option (and associated dependency) would also make it easier to decouple the app as suggested in Daytrader-23. I like the idea of splitting up the modes by category and doing a little renaming to make them more descriptive. Persistence Run-time Modes (one has to be selected) 1) Direct (or JDBC) 2) Stateless Session Bean to Direct 3) Full EJB (Stateless Session Bean to Entity Beans) JMS Support Enablement (any can be selected) - Publish Quote Updates (Publish quote price changes to a JMS topic) - Process Buy/Sell Orders using XA (Asychronously process buy/sell orders by placing them on a JMS queue. An MDB is then responsible for reading a message form the queue and completing the order) Thoughts? > Set publichQuotePriceChange to true in ejb-jar.xml so that MDBs get accessed > during Daytrader scenario runs > ----------------------------------------------------------------------------------------------------------- > > Key: DAYTRADER-22 > URL: http://issues.apache.org/jira/browse/DAYTRADER-22 > Project: DayTrader > Issue Type: Bug > Components: EJB Tier > Affects Versions: 1.2 > Reporter: Piyush Agarwal > Assigned To: Matt Hogstrom > Fix For: 1.2 > > Attachments: Daytrader-22.patch > > > Currently the publishQuotePriceChange is set to False in the ejb-jar.xml and > this causes the TradeStreamerMDB to NOT be accessed during the Daytrader > trading runs. The TradeStreamerMDB listens to the JMS messages and invokes > the logging code to log the debug and trace messages during the runs. > Updating the flag to true enables this functionality. -- This message is automatically generated by JIRA. - If you think it was sent incorrectly contact one of the administrators: http://issues.apache.org/jira/secure/Administrators.jspa - For more information on JIRA, see: http://www.atlassian.com/software/jira
