Run parallel queries

If you are running queries in parallel using the HCL OneDB™ parallel database query (PDQ) feature and the iterator UDR in the FROM clause is not parallelizable, query parallelism is turned off for the SELECT query. However, if the iterator UDR in the FROM clause is parallelizable and no other factors disable the query parallelism, the query can run in parallel. When PDQ is on, functional tables are treated as single non-fragmented tables.

In the following example, the GROUP BY and aggregation operations can be run by multiple PDQ threads and the fibseries() function can be run by a secondary thread.
SELECT col1,col2, COUNT(*) FROM TABLE (FUNCTION fibseries(10)) 
tab1(col1),tab2
GROUP BY col1,col2;

Refer to your HCL OneDB Performance Guide for information about running queries in parallel.