RE: Parallel INSERT SELECT take 2

Hi,

Based on the discussion in another thread[1], we plan to change the design like
the following:

allow users to specify a parallel-safety option for both partitioned and
non-partitioned relations but for non-partitioned relations if users didn't
specify, it would be computed automatically? If the user has specified
parallel-safety option for non-partitioned relation then we would consider that
instead of computing the value by ourselves.

In this approach, it will be more convenient for users to use and get the
benefit of parallel select for insert.

Since most of the technical discussion happened in another thread, I
posted the new version patch including the new design to that thread[2].
Comments are also welcome in that thread.

[1] https://www.postgresql.org/message-id/CAA4eK1%2BMQnm6RkqooHA7R-y7riRa84qsh5j3FZDScw71m_n4OA%40mail.gmail.com

[2]
https://www.postgresql.org/message-id/OS0PR01MB5716DB1E3F723F86314D080094F09%40OS0PR01MB5716.jpnprd01.prod.outlook.com

Best regards,
houzj