[ACCUMULO-1962] Improve batch scanner throughput in failure case

• Type: Improvement
• Status: Resolved
• Priority: Major
• Resolution: Duplicate
• Assignee: Unassigned
• Reporter: Keith Turner
• Created: 04/Dec/13 15:56
• Updated: 23/Apr/19 16:09
• Resolved: 23/Apr/19 15:45

Description

The batch scanner currently does the following.

1. bin ranges to tablets servers and tabelts
2. if any ranges could not be binned (e.g. a tablet had no location) goto 1
3. queue up work for tablet servers on a thread pool
4. wait for thread pool to complete all work
5. if there were any failures goto 1

In the face of failures (tablets not assigned because of migration, tablet servers dying) it would be better if the batch scanner worked on what it could and immediately requeued failures for processing immediately. The ConditionalWriter and BatchWriter have failure queues and increase the retry time if something keeps failing.