What's the format of Cassandra's timestamp, microsecond or millisecond?

[yhqruc]

Hi, All:    When I use cassandra.thrift API to manipulate the data, the 
timestamp is in millisecond. It can be verified in cli:[default@ks_wwapp] get 
cf_user['100031'];
=> (super_column=01#uid#,
     (name=0#d#, value=bf86010000000000, timestamp=1438689394196))
   When I use cli to set a column, the timestamp is in microseconds. Such 
as:[default@ks_wwapp] get cf_user['100049'];
=> (super_column=sc_name,
     (name=c_name, value=635f76616c7565, timestamp=1439184495344000))
Now, I can't use cassandra.thrift API to update the key 100049. 
What's wrong with cassandra?
Thanks!