To understand the transaction processing flow and the effects of certain configuration properties on transaction processing, you should first know these terms:

• Request

• Unit of work

• Transaction

A request is equivalent to the contents of the buffer. It can contain a single statement or a batch of statements. During a request, the client application gives up control to the Database Management System (DBMS) and waits for a response.

A unit of work is one or more requests that are committed or rolled back as a group. If all the requests process successfully, the unit of work is committed, and the requested changes to the database are permanent.

A transaction is a set of SQL statements terminated with a commit or rollback operation. It is equal to a unit of work and can span many requests.