[#797] add comment for hbase table and TTL config

 add comment for hbase table and TTL config

scripts/README.md

@@ -14,4 +14,23 @@ For example, you can create Pinpoint tables by running the following line from s
 
 `$HBASE_HOME/bin/hbase shell $PATH_TO_SCRIPTS/hbase-create.hbase`
 
-*hbase-flush-table.hbase*, and *hbase-major-compact-htable.hbase* are there purely for maintenance.
+*hbase-flush-table.hbase*, and *hbase-major-compact-htable.hbase* are there purely for maintenance.
+
+## HBase Table Description
+
+* ApplicationIndex, HostApplicationMap  : Tables for applicationIds and agentIds registered under them
+* AgentInfo : Table for basic agent information ex) ip, hostname agentversion, start time, etc
+* AgentStat : Table for agent’s statistical data ex) cpuload, gc, heap etc
+* AgentLifeCycle : Table for agent’s life cycle data.
+* AgentEvent : Table for various agent events ex) request for thread dump, etc
+* ApiMetaData : Meta-table for method information
+* SqlMetaData : Meta-table for sql statements
+* StringMetaData : Meta-table for string values  ex) method arguments, exception names, etc
+* ApplicationTraceIndex : Index table for trace data
+* Traces : Table for traced transactions
+* ApplicationMapStatisticsCaller, ApplicationMapStatisticsCallee, ApplicationMapStatisticsSelf : Table for storing rpc statistics between various agents
+
+## About TTL config
+- You do not have to use the TTL value set in the HBase script files. You may set it to any desired period to hold data that fits your specific needs/environment.
+- The ratio of TTL values do not need to be strictly followed as well. The reason that some table's TTL value is higher is because they would contain data that would affect data in other tables if deleted.
+ex) We set a high TTL value for ApiMetaData table, because if the TTL value is shorter than an agent’s lifespan and the api metadata is deleted, trace information cannot be reconstructed properly.