rajeshbabu created HBASE-10498:
----------------------------------

             Summary: Add new APIs to load balancer interface
                 Key: HBASE-10498
                 URL: https://issues.apache.org/jira/browse/HBASE-10498
             Project: HBase
          Issue Type: Improvement
          Components: Balancer
            Reporter: rajeshbabu
            Assignee: rajeshbabu
             Fix For: 0.99.0


If a custom load balancer required to maintain region and corresponding server 
locations,
we can capture this information when we run any balancer algorithm before 
assignment(like random,retain).
But during master startup we will not call any balancer algorithm if a region 
already assinged
During split also we open child regions first in RS and then notify to master 
through zookeeper. 
So split regions information cannot be captured into balancer.

Since balancer has access to master we can get the information from online 
regions or region plan data structures in AM.
But some use cases we cannot relay on this information(mainly to maintain 
colocation of two tables regions). 

So it's better to add some APIs to load balancer to notify balancer when 
*region is online or offline*.

These APIs helps a lot to maintain *regions colocation through custom load 
balancer* which is very important in secondary indexing. 



--
This message was sent by Atlassian JIRA
(v6.1.5#6160)

Reply via email to