ISGQUERY and GQSCAN processing overview

In a global resource serialization star sysplex, the basic flow of a GQSCAN/ISGQUERY request for global resource information is illustrated by the high level diagram in Figure 1.

Figure 1. Overview of GQSCAN/ISGQUERY request for global resource data

The flow, as illustrated in Figure 1, is as follows:

The request for global resource information is queued to the GQSCAN/ISGQUERY server on that system.
Global resource serialization suspends the GQSCAN/ISGQUERY requester. For GQSCAN/ISGQUERY users that do not need information about other systems and can not tolerate suspension, see Cross-system processing option.
Global resource serialization processing will then package the request for transmission and send it to each of the other systems in the star complex.
Each system in the complex scans its system global resource queue for global resource requests that match the GQSCAN/ISGQUERY selection criteria, and respond to the originating system server with the requested global resource information, if any, and a return code.
The originating system waits for responses from all of the systems in the sysplex and builds a composite response, which is returned to the caller's output area through the GQSCAN/ISGQUERY back-end processing. Control is then returned to the caller with the appropriate return code.