Global Transactions

Global transactions allow an application to modify data managed by different resource managers within a single unit of work. The Recoverable Resource Manager Services (RRS) component of z/OS manages the unit of work for the application and coordinates the activities of the participating resource managers. DB2 participates as a resource manager in global transactions, as do MQ Series, IMS, and other products. When using a global transaction, an application needs to use interfaces defined by RRS to commit or roll back work. These transactions will be identified via a tokenglobal transaction ID, or XID.

Within DB2, global transactions allow several processes to share locks if they are all participants in a unit of work. The larger unit of work is referred to as a global transaction. This provides a way to avoid deadlocks between separate threads that are part of the same work unit.

The sharing of locks is limited to normal transaction locks and an explicit LOCK TABLE statement, or partition-key updates could still cause deadlocks or timeouts. Many design issues need to be considered prior to the use of global transactions, and there are also additional risks and exposures.

DB2 for z. OS Version 8 DBA Certification Guide
DB2 for z/OS Version 8 DBA Certification Guide
ISBN: 0131491202
EAN: 2147483647
Year: 2003
Pages: 175
Authors: Susan Lawson © 2008-2017.
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