[IMPALA-8999] Parallelise all plans, including UNION, when mt_dop > 1

• Type: Sub-task
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Fix Version/s: Impala 3.4.0
• Component/s: Distributed Exec
• Epic Color: ghx-label-10
• Assignee: Tim Armstrong
• Reporter: Tim Armstrong
• Created: 02/Oct/19 22:42
• Updated: 24/Oct/19 06:28
• Resolved: 24/Oct/19 06:28

Description

We should do another pass over the scheduler to make sure that the logic makes sense for mt_dop.

There are some comments in scheduler.cc, e.g. talking about optimisations for UNION.