SQL400E - Temporary distributed result file &1 was created while processing distributed subquery

SQL400E
Message Text: Temporary distributed result file &1 was created while processing distributed subquery
Cause Text: A temporary distributed result file was created to contain the intermediate results of the query. The query contains a subquery which requires an intermediate result.
Recovery Text: Generally, if the fields correlated between the query and subquery do not match the partition keys of the respective files, the query must be processed in multiple steps and a temporary distributed file will be built to contain the intermediate results.

For more information about the processing of distributed files, refer to the Distributed Database Programming information.