Global resource serialization searches the RNLs, unless an ENQ or DEQ is coded with RNL=NO or an ISGNQXIT or ISGNQXITFAST installation exit changes the request indicating to bypass RNL processing. When RNL=NO, global resource serialization bypasses the RNL search. The default, however, is RNL=YES. Figure 1 summarizes the processing for a resource requested by an ENQ or DEQ macro. The figure shows how global resource serialization uses the scope of the request, changes (if any) made by an ISGNQXIT or ISGNQXITFAST exit, and the RNLs to determine if the resource is a local or global resource. It also shows when global resource serialization internally changes the scope of the resource.

For an ENQ or DEQ request with a scope of SYSTEM, global resource serialization first scans the SYSTEM inclusion RNL. If it finds a match, it changes the scope to SYSTEMS and then scans the SYSTEMS exclusion RNL.

For an ENQ or DEQ request with a scope of SYSTEMS, global resource serialization scans only the SYSTEMS exclusion RNL.

Figure 1. ENQ and DEQ processing summary

For a RESERVE request, global resource serialization first scans the SYSTEMS exclusion RNL to see if it should treat the resource as a local resource or as a global resource. If the resource is not named in the RNL and is thus a global resource, then global resource serialization scans the RESERVE conversion RNL to see if the global resource requires a reserve. If the resource is named in the SYSTEMS exclusion RNL, global resource serialization does not search the RESERVE conversion RNL; it treats the resource as a local resource and allows the system to issue the reserve.

Figure 2 summarizes the processing done for a resource requested by a RESERVE macro. The figure shows that global resource serialization first scans the SYSTEMS exclusion RNL to determine whether or not the resource is global. If there is no match, it scans the RESERVE conversion RNL to determine whether or not the system is to issue a reserve. Figure 2 also shows when global resource serialization internally changes the scope of a resource requested by a RESERVE macro.

Figure 2. RESERVE Processing Summary