Use of Transactions

A transaction guarantees that all messages produced or consumed within the scope of the transaction will be either processed (committed) or not processed (rolled back) as a unit. In general, the overhead of both local and distributed transaction processing dwarfs all other performance differentiators.

A message produced or consumed within a transaction is slower than those produced or consumed outside of a transaction for the following reasons:

• Additional information must be stored with each produced message.

• In some situations, messages in a transaction are stored when normally they would not be. For example, a persistent message delivered to a topic destination with no subscriptions would normally be deleted, however, at the time the transaction is begun, information about subscriptions is not available.

• Information on the consumption and acknowledgement of messages within a transaction must be stored and processed when the transaction is committed.