[SPARK-17911] Scheduler does not need messageScheduler for ResubmitFailedStages

• Type: Improvement
• Status: Resolved
• Priority: Major
• Resolution: Incomplete
• Affects Version/s: 2.0.0
• Component/s: Scheduler, Spark Core
• Labels: bulk-closed
• Assignee: Unassigned
• Reporter: Imran Rashid
• Created: 13/Oct/16 15:24
• Updated: 17/May/20 17:48
• Resolved: 21/May/19 04:34

Description

Its not totally clear what the purpose of the messageScheduler is in DAGScheduler. It can perhaps be eliminated completely; or perhaps we should just clearly document its purpose.

This comes from a long discussion w/ markhamstra on an unrelated PR here: https://github.com/apache/spark/pull/15335/files/c80ad22a242255cac91cce2c7c537f9b21100f70#diff-6a9ff7fb74fd490a50462d45db2d5e11

But its tricky so breaking it out here for archiving the discussion.

Note: this issue requires a decision on what to do before a code change, so lets just discuss it on jira first.