Use of Transactions

A transaction guarantees that all messages produced in a transacted session and all messages consumed in a transacted session will be either processed or not processed (rolled back) as a unit. The C-API supports local transactions. In general the overhead of transaction processing dwarfs all other differentiators.

A message produced or acknowledged in a transacted session is slower than in a non-transacted session 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.