IMS Connectivity in an On Demand Environment: A Practical Guide to IMS Connectivity

302 IMS Connectivity in an On Demand Environment: A Practical Guide to IMS Connectivity

4. Check if IMS is experimenting global problems. The IMS troubleshooting procedures are

beyond the scope of this book. If you know that the IMS problems will not be solved in a

short period of time, and you are experiencing a lot of execution timeouts, lengthening the

IMS Connect TIMEOUT value or using the IMS Connect Extensions pacing feature to

diminish the IMS workload should alleviate this problem.

Unless you find a configuration problem, there are very few things that can be done on the

IMS Connect side to fix an execution timeout situation. The problem will be either in IMS or on

the application side. However, ensure that the timeout values used in your applications and in

IMS Connect are set appropriately.

15.2 Error messages from IMS

You can get IMS error messages in the form of literals, which begin with an error code,

expressed as DFSnnnn, where nnnn is a code that specifies the kind of error.

If you are using IMS Connector for Java, the way DFS messages are handled is depends on

the type of imsRequestType that was used for the interaction. If the imsRequestType was

IMS_REQUEST_TYPE_IMS_ COMMAND or

IMS_REQUEST_TYPE_MFS_TRANSACTION, DFS messages are treated as normal output

and, assuming that there are no other problems with the output, no exception is thrown. If the

imsRequestType was IMS_REQUEST_TYPE_IMS_ TRANSACTION, DFS messages are

treated as errors. In this last case, IMS Connector for Java throws an exception, as shown in

Example 15-6.

Example 15-6 Exception thrown when IMS sends a DFSxxxx message

com.ibm.connector2.ims.ico.IMSDFSMessageException: ICO0079E:

[e-mail](InteractionSpec

) error. IMS returned DFS message: DFS065 17:58:27 TRAN/LTERM STOPPED

If you are using the socket interface with a non-IMS Connector for Java client, you will get the

DFS message as a normal IMS response (followed by the CSM block). However, there is an

important difference between a normal IMS response and

some of the DFS status messages:

In some cases, you must

not send an ACK after you get a DFS message. That is the reason

why the recommended way to decide if you need to send an ACK is to check the flag byte

present both in the CSM and RSM blocks, instead of relying on your own program logic.

15.3 Wrong status codes from IMS Connect

IMS Connect uses the RSM message structure to notify non-IMS Connector for Java client

applications of any special situation. This refers not only to error or exception situations, but

also to informational codes associated with a normally ended interaction. The RSM structure

contains a return code and a reason code that describe the detected situation.

In this section, we analyze some of the error conditions reported in an RSM, the method to

diagnose it, and the measures you can take to correct the situation.