HBASE-1502 Remove need for heartbeats in HBase
Review Request #647 - Created April 22, 2011 and updated
This patch does not completely remove heartbeats. It unburdens the heartbeat of control messages; now heartbeat is used to send the master load only (At most recent hackathon we had rough agreement that we'd keep heartbeat to carry load)... if we miss some, no biggie. RPC version changed on HMasterRegionInfo since the regionServerStartup and regionServerReport arguments have changed. We pass a String now instead of HServerAddress so this should help with our DNS issues where the two sides disagree. Removed HMsg. HServerAddress as been sort_of_deprecated. Its in our API so can't remove it easily (its embedded inside HRegionLocation). Otherwise, we don't use it internally anymore. HServerInfo is deprecated. Server meta data is now available in new class ServerName and load lives apart from HSI now. Fixed up regionserver and master startup so they now look the same. New tests Cruft cleanup.
Most tests pass. I have yet to run it on a cluster. Doing that now.