Metrics values have same names as old cassandra plugin (#4080)

plugins/inputs/jolokia2/examples/cassandra.conf

@@ -10,6 +10,7 @@
     name  = "GarbageCollector"
     mbean = "java.lang:name=*,type=GarbageCollector"
     tag_keys = ["name"]
+    field_prefix = "$1_"
 
 [[inputs.jolokia2_agent]]
   urls = ["http://localhost:8778/jolokia"]
@@ -19,67 +20,76 @@
     name  = "Cache"
     mbean = "org.apache.cassandra.metrics:name=*,scope=*,type=Cache"
     tag_keys = ["name", "scope"]
+    field_prefix = "$1_"
 
   [[inputs.jolokia2_agent.metric]]
     name  = "Client"
     mbean = "org.apache.cassandra.metrics:name=*,type=Client"
     tag_keys = ["name"]
+    field_prefix = "$1_"
 
   [[inputs.jolokia2_agent.metric]]
     name  = "ClientRequestMetrics"
     mbean = "org.apache.cassandra.metrics:name=*,type=ClientRequestMetrics"
     tag_keys = ["name"]
+    field_prefix = "$1_"
 
   [[inputs.jolokia2_agent.metric]]
     name  = "ClientRequest"
     mbean = "org.apache.cassandra.metrics:name=*,scope=*,type=ClientRequest"
     tag_keys = ["name", "scope"]
+    field_prefix = "$1_"
 
   [[inputs.jolokia2_agent.metric]]
     name  = "ColumnFamily"
     mbean = "org.apache.cassandra.metrics:keyspace=*,name=*,scope=*,type=ColumnFamily"
     tag_keys = ["keyspace", "name", "scope"]
+    field_prefix = "$2_"
 
   [[inputs.jolokia2_agent.metric]]
     name  = "CommitLog"
     mbean = "org.apache.cassandra.metrics:name=*,type=CommitLog"
     tag_keys = ["name"]
+    field_prefix = "$1_"
 
   [[inputs.jolokia2_agent.metric]]
     name  = "Compaction"
     mbean = "org.apache.cassandra.metrics:name=*,type=Compaction"
     tag_keys = ["name"]
+    field_prefix = "$1_"
 
   [[inputs.jolokia2_agent.metric]]
     name  = "CQL"
     mbean = "org.apache.cassandra.metrics:name=*,type=CQL"
     tag_keys = ["name"]
+    field_prefix = "$1_"
 
   [[inputs.jolokia2_agent.metric]]
     name  = "DroppedMessage"
     mbean = "org.apache.cassandra.metrics:name=*,scope=*,type=DroppedMessage"
     tag_keys = ["name", "scope"]
+    field_prefix = "$1_"
 
   [[inputs.jolokia2_agent.metric]]
     name  = "FileCache"
     mbean = "org.apache.cassandra.metrics:name=*,type=FileCache"
     tag_keys = ["name"]
+    field_prefix = "$1_"
 
   [[inputs.jolokia2_agent.metric]]
     name  = "ReadRepair"
     mbean = "org.apache.cassandra.metrics:name=*,type=ReadRepair"
     tag_keys = ["name"]
-
-  [[inputs.jolokia2_agent.metric]]
-    name  = "HintedHandoffManager"
-    mbean = "org.apache.cassandra.metrics:type=HintedHandoffManager"
+    field_prefix = "$1_"
 
   [[inputs.jolokia2_agent.metric]]
     name  = "Storage"
     mbean = "org.apache.cassandra.metrics:name=*,type=Storage"
     tag_keys = ["name"]
+    field_prefix = "$1_"
 
   [[inputs.jolokia2_agent.metric]]
     name  = "ThreadPools"
     mbean = "org.apache.cassandra.metrics:name=*,path=*,scope=*,type=ThreadPools"
     tag_keys = ["name", "path", "scope"]
+    field_prefix = "$1_"