Improving query performance by setting fetch size

You can optimize query performance by setting the number of records to retrieve in batch retrieval mode.

In the IMS Universal DL/I driver, a list of rows is represented by a Path instance containing one or more segments that match the segment search argument criteria specified by an SSAList. The fetch size is the number of rows physically retrieved from the IMS database per network call. This is set for you internally. You can also set the fetch size using the setFetchSize method from the PCB interface. Setting the fetch size allows a single request to return multiple rows at a time, so that each application request to retrieve the next row does not always result in a network request. If the fetch size was n and the IMS Universal DL/I driver application requires more than the previous n number of rows during a batch retrieve operation, another network call will be made on behalf of the application to retrieve the next n number of rows that match the segment search argument criteria.