unit of recovery, resolving in-doubt units of recovery, RRS (Resource Recovery Services), Resource Recovery Services (RRS)" /> How in-doubt units of recovery are resolved from RRS

 

How in-doubt units of recovery are resolved from RRS

One of the functions of the RRS adapter is to keep data synchronized between WebSphere MQ and other RRS-participating resource managers. If a failure occurs when WebSphere MQ has completed phase one of the commit and is waiting for a decision from RRS (the commit coordinator), the unit of recovery enters the in-doubt state.

When communication is reestablished between RRS and WebSphere MQ, RRS automatically commits or backs out each unit of recovery, depending on whether there was a log record marking the beginning of the commit. WebSphere MQ cannot resolve these in-doubt units of recovery (that is, commit or back out the changes made to WebSphere MQ resources) until the connection to RRS is reestablished.

Under some circumstances, RRS cannot resolve in-doubt units of recovery. When this happens, WebSphere MQ sends one of the following messages to the z/OS console:

For details of what these messages mean, see the WebSphere MQ for z/OS Messages and Codes manual.

For all resolved units of recovery, WebSphere MQ updates the queues as necessary and releases the corresponding locks. Unresolved units of recovery can remain after restart. Resolve them by the method described in the WebSphere MQ for z/OS System Administration Guide.