[HBASE-6404] Collect p95 stats for get/put/delete/next

Author: gauravm

Summary: Collect p95 stats for get / put / delete / next operations by having a histogram and a percentile metric (with percentile = 0.95) for each operation, respectively. The method of stat collections is similar to D715751.

Test Plan: Unit tests and checked on Titan Shadow.

Reviewers: liyintang, adela, manukranthk

Reviewed By: manukranthk

CC: hbase-eng@

Differential Revision: https://phabricator.fb.com/D779670

Task ID: 1200149

git-svn-id: https://svn.apache.org/repos/asf/hbase/branches/0.89-fb@1480004 13f79535-47bb-0310-9956-ffa450edef68
[HBASE-8484] Adding diagnostic messages when the RegionServer hists an IOException in RegionServerReport

Author: manukranthk

Summary: This diff adds instrumentation in the case when we catch IOException in regionserver report.

Test Plan: Tested on Dev Cluster by killing the master.

Reviewers: aaiyer

Reviewed By: aaiyer

Differential Revision: https://phabricator.fb.com/D797516

git-svn-id: https://svn.apache.org/repos/asf/hbase/branches/0.89-fb@1480005 13f79535-47bb-0310-9956-ffa450edef68
[HBASE-8491] Fixing the TestHeapSizes.

Author: manukranthk

Summary: Accounting for the extra references added. Did an absolute count of non static variables and updated accordingly.

Test Plan: Unit Tests

Reviewers: liyintang

Reviewed By: liyintang

CC: hbase-eng@

Differential Revision: https://phabricator.fb.com/D799334

git-svn-id: https://svn.apache.org/repos/asf/hbase/branches/0.89-fb@1480006 13f79535-47bb-0310-9956-ffa450edef68
[HBASE-8500] Adds a RollingRestart utility for a region server

Author: rshroff

Summary:
The change adds a basic RollingRestart utility which can be performed at
region server level. It also adds a basic RegionChecker which gets the
availability of the region during the rolling restart.

The changes in the master code path is to have more finer grained
control on region servers which are black listed. Plus a bug fix in the
canOffloadTo()

You can now trigger a RollingRestart of region server on the host by
issuing:
*HBASE/bin/hbase org.apache.hadoop.hbase.util.RollingRestart -c -s hbasedev128.ash3

  // Test

Test Plan:
mr, plus did a RollingRestart of a region server on dev
cluster(Sample output https://phabricator.fb.com/P2126823)

Reviewers: aaiyer, liyintang, manukranthk, adela

Reviewed By: aaiyer

CC: hbase-eng@, paultuckfield

Differential Revision: https://phabricator.fb.com/D796086

Task ID: 2229110

git-svn-id: https://svn.apache.org/repos/asf/hbase/branches/0.89-fb@1480007 13f79535-47bb-0310-9956-ffa450edef68