Requesting Restart

When a restartable Universal Connector command is initiated, it is either an initial instance or a restarted instance of a command ID.

The RESTART option is specified on the command line with parameter -restart. RESTART specifies whether or not the Universal Connector command instance is requesting a restart of a previous command ID. Possible RESTART values are yes, no, or auto.

The auto value specifies that if there is no existing command ID job on the SAP system, consider this Universal Connector execution the first instance. If there is an existing command ID job, consider this a restart of the command ID. The auto value permits automatic restart by eliminating the need to modify the RESTART value for the initial instance and restarted instance.

It is important to note that when using the RESTART auto value, Universal Connector will not start a new instance of a process chain on the SAP system if a job matching the chain ID/command ID exists in the SAP system. Universal Connector will continue to reconnect to the existing SAP process chain.

Without considering the behavior resulting from the use of RESTART auto, it may be possible for one to assume that a process chain has been run multiple times when, in fact, Universal Connector has been reconnecting to the same process chain instance. Informational messages are printed by Universal Connector to standard error to indicate the reconnected status but, if the message level is not set to info, the messages will not be seen.

It is also important to note that in the context of client fault tolerant process chain commands, the term RESTART refers to the logical unit of work that involves the Universal Connector and the SAP process chain instance. A restart of this logical unit of work does not necessarily restart the process chain instance on the SAP system. The restart alone is actually a "reconnect" to the process chain instance. In order to actually restart the process chain instance on the SAP system, the FORCE configuration option must be added to the command line (-force yes).

Controlling Auto Restart

Misunderstanding the auto restart behavior described above can potentially have serious consequences. For this reason, the ALLOW_AUTO_RESTART lets you allow or disallow the use of auto restart. You can make this specification in the Universal Connector configuration file and override it on the command line.