Filtering Trace Data by User ID

By default, an ATBTRACE START request specifies USERID(*), which results in trace data for all conversations for the LU and TP combination, including conversations allocated without a user ID. To filter the amount of trace data, you may specify either the USERID or SECNONE keyword on the START request. With the USERID keyword, for example, you could issue the following request on system MVS01:

ATBTRACE START DSN(TRACE.DS) LU(LUA) TP(TPA) USERID(GOODWIN)

In this case, APPC/MVS on the MVS01 system compares not only these LU name and TP name values, but also the user ID value, with those specified (explicitly or implicitly) on both inbound and outbound Allocate requests. So the trace data you collect consists only of those conversations for which the LU, TP, and user ID values for the START and Allocate requests match.

If a TP allocates a conversation with TPA, specifying a security type with security fields that LUA cannot support, the system downgrades the Allocate request by stripping out the security fields that are not supported. For example, if a TP issues the Allocate request with security_same, but the APPL definition statement for the LUA specifies CONV or NONE, the system strips out the user ID value specified on the Allocate request. In this case, APPC/MVS does not trace the conversations because the user ID value on the START request (user ID GOODWIN) does not match the user ID value on the inbound Allocate request (the user ID is missing).

If you want to make sure you are collecting trace data for inbound conversations for which the user ID is not passed, enter another START request for the LU/TP combination, this time specifying the SECNONE keyword instead of USERID. If you do so, APPC/MVS traces all conversations with matching LU/TP values and a Security_type of security_none, along with conversations with matching LU/TP/USERID values. Even though the resulting trace data might contain information for some extraneous security_none conversations, you probably have less trace data to sort than if you used the default of tracing all conversations for the LU/TP combination.