Processing Overview

At start-up, CRCN reports the initial state of the RMs by emitting the following messages:

CASXO0041I The XA connection monitoring
transaction CRCN started using a 00020 seconds interval.

This message is followed by a message similar to the following:

CASXO0034I CRCN started monitoring: XAMQ Enabled, XADB Enabled, XAOR Enabled.

Where XAMQ, XADB, and XAOR represent active and connectable resource managers marked as Enabled at region start-up.

Note: An RM marked as Disabled at region start-up is not monitored by CRCN until its state, in MFDS, is changed to Enabled using the dynamic XA feature. When this change of state takes place, CRCN starts monitoring this resource automatically.

To verify connectivity, CRCN uses a new function of the XA switch: -- xa-ping.

This entry point pings the resource manager, which then confirms that it is connectable. The ping is a simple call/API into the RM; see Pinging the Resource Manager (xa-ping) for details on the call for each XA switch.

If xa-ping does not return a code of 0, this signals to the transaction that a resource manager cannot be contacted. In this case, the following messages appear in the console:

CASXO0038I XA resource XAMQ has now been disabled. 
CASXO0031W ES has lost connection to the RM XAMQ, attempting to reconnect.

The first message indicates that CRCN sent a request to all processes to close the connection to the resource managers. The last process to fulfil the request emits this message. The second message indicates that the connection to the resource manager has been lost and that Enterprise Server is attempting to restore the connection.

Note: On the first failure, the attempt to reconnect takes place after the duration of the DELAY if CRCN detected the connection. If another process flagged the CRCN disconnect, the reconnect takes place on the next CRCN monitoring cycle.