1.1.2.6 Single Group Multiple Branches (SGMB)

In previous releases, servers in the same group use the same transaction branch in a global transaction; if these servers connect to different instances on the same RAC, the transaction branch may fail and an XA error, XAER_AFFINITY, will be reported, meaning one branch cannot go through different instances. For this reason, Tuxedo groups can only use singleton RAC services. A DTP service (if the DTP option, -x in srvctl, is specified) or a service offered by only one instance could be a singleton RAC service.

In this release, this feature eliminates the need to use singleton RAC service when multiple servers in a server group participate in the same global transaction. If servers in the same server group and same global transaction happen to connect to different RAC instances, a different transaction branch is used. Thus, such applications can balance the load across the available RAC instances.

For more information about configuration, see Introduction to Using Oracle Tuxedo Advanced Performance Pack.

Note:

The transaction still fails if more than 16 instances are involved in a single group.