In Extended Parallel Server, when you specify a range of values in SET PDQPRIORITY, you allow the Resource Grant Manager (RGM) some discretion in allocating resources.
The high value in the range is the desired resource allocation, while the low value is the minimum acceptable resource allocation for the query. If the low value exceeds the available system resources, the RGM blocks the query. Otherwise, the RGM chooses the largest PDQ priority in the specified range that does not exceed available resources.
For information about configuration parameters and about the Resource Grant Manager, see your IBM Informix Administrator's Guide and your IBM Informix Performance Guide.
For information about the PDQPRIORITY environment variable, see the IBM Informix Guide to SQL: Reference.