[jira] [Created] (HBASE-17462) Investigate using sliding window for read/write request costs in StochasticLoadBalancer

["Ted Yu (JIRA)" <ji...@apache.org>]

Ted Yu created HBASE-17462:
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             Summary: Investigate using sliding window for read/write request costs in StochasticLoadBalancer
                 Key: HBASE-17462
                 URL: https://issues.apache.org/jira/browse/HBASE-17462
             Project: HBase
          Issue Type: Improvement
            Reporter: Ted Yu


In the thread, http://search-hadoop.com/m/HBase/YGbbyUZKXWALkX1, Timothy was asking whether the read/write request costs in StochasticLoadBalancer should be calculated as rates.

This makes sense since read / write load on region server tends to fluctuate over time. Using sliding window would reflect more recent trend in read / write load.

Some factors to consider:

The data structure used by StochasticLoadBalancer should be concise. The
number of regions in a cluster can be expected to approach 1 million. We
cannot afford to store long history of read / write requests in master.

Efficiency of cost calculation should be high - there're many cost
functions the balancer goes through, it is expected for each cost function
to return quickly. Otherwise we would not come up with proper region
movement plan(s) in time.




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