[TEZ-2599] Dont send obsoleted data movement events to tasks

• Type: Improvement
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 0.8.0-alpha
• Hadoop Flags: Reviewed
• Assignee: Bikas Saha
• Reporter: Bikas Saha
• Created: 02/Jul/15 23:05
• Updated: 01/Sep/15 21:31
• Resolved: 04/Jul/15 08:19

Description

Since events are sent in bulk and in sequential order to tasks they can end up getting a bunch of data movement events in round 1 and then an input failed event in round 2. The task may end up scheduling fetches for these obsoleted events before round 2, leading to wastage.
Given that an input failed event and data movement event can be matched via their source task attempt ids, the AM can use this match to obsolete the data movements events ahead of time and not send them to the tasks in the first place.
The input failed events still need to be sent to the tasks, so that they can obsolete any data movements events that they may have received much earlier from the failed task attempt.

Issue Links

• duplicates: TEZ-924 InputFailedEvent handling for Shuffle