DB Engine :: Forcing INSERT / SELECT To Use A Parallel Plan

I’ve been looking at a bug in an application stored proc. This merely inserts 7 million rows from one table into another (empty) table.

INSERT 
dbo.TradeDataPrimary
(Id, SinaiTrade) 
SELECT 
ts.Id,
CAST(ts.XmlTrade
AS varbinary(MAX))
FROM dbo.TradePrimary ts

Both tables have a clustered index with the same key order (on the first column) but the query optimizer insisted on placing a SORT step in the query plan. This use a lot of tempdb which I wanted to avoid.

I discovered that the bug was a data type mismatch. Fixing the bug and/or dropping the clustered index from the target table before the insert resulted in the plan I expected, that is, with no sort.

I was hoping it would run faster but, unfortunately, as can be seen from the new plan below, a serial plan is used. This results in the insert taking nearly three times as long as the original.

I’ve been looking at Paul White’s article: [URL] ....
and Adam Machanic’s: [URL] ....

Both are excellent articles but neither approaches i.e. trace flag 8649 or make_parallel () give me a parallel plan. Am I missing a trick here? How I can force parallelism? I know there are no features that require a serial zone in the plan otherwise the plan with the sort would not be parallel..

This is SQL Server 2012 Enterprise 11.0.5522.0, 512 GB of RAM and 16 procs.