[ http://issues.apache.org/jira/browse/DAYTRADER-29?page=all ]
Christopher James Blythe updated DAYTRADER-29:
----------------------------------------------
Summary: Async 1-Phase mode should be removed (was: Asyc 1-Phase mode
should be removed)
> Async 1-Phase mode should be removed
> ------------------------------------
>
> Key: DAYTRADER-29
> URL: http://issues.apache.org/jira/browse/DAYTRADER-29
> Project: DayTrader
> Issue Type: Improvement
> Components: EJB Tier
> Affects Versions: 1.2, 2.0
> Reporter: Christopher James Blythe
>
> Here are some comments that I added to DT-22...
> 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 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. As an added benefit of removing this option, we would remove a
> dependency between the TradeDirect and TradeBean code.
> I also 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?
--
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
