Support for parallel execution of complex DML statements

Intra-query parallelism does not provide any benefits for the "INSERT ... SELECT..." statements, even when insert is performed into a temporary table.

While preparing a PoC for the customer planning to use DB2 for LUW in 1C:Enterprise application configurations, I have found that intra-query parallelism does not provide any benefits for the "INSERT ... SELECT..." statements.

1C:Enterprise application platform systematically uses the following approach for the reporting:
(a) declare a set of global temporary tables (DGTTs)
(b) fill the DGTTs by using the "INSERT ... SELECT ..." statements
(c) fetch the results by combining data from several DGTTs

In some cases on stage (b) the "SELECT" part is pretty complex, and would really benefit from complex query support (specifically from parallel query processing).

The tests I have performed show that query execution time is nearly the same with INTRA_PARALLEL enabled or not, although the plans in this two cases are different. This behavior is the same between all current DB2 versions (9.7, 10.1 and 10.5).

I got the information from the DB2 Support, that parallel IUD operations are currently not implemented, and are even not in the development roadmap.

This would not be a problem if a competing database product (specifically, MS SQL Server) was not able to speed up the same queries by using parallel execution. For my particular tests, MSSQL is able to execute the query in 28 seconds (by using many CPU cores), while DB2 requires 89 seconds for the same query (and uses only one CPU core for it most of the time).