confusing RocksDBStateBackend parameters

[Bowen Li]

Hello guys,
      I've been trying to figure out differences among several parameters
of RocksDBStateBackend. The confusing parameters are:

      In flink-conf.yaml:
      1. state.backend.fs.checkpointdir
      2. state.backend.rocksdb.checkpointdir
      3. state.checkpoints.dir

      and
       4. the param *'**checkpointDataUri**'* you pass in to
RocksDBStateBackend
constructor in`public RocksDBStateBackend(*URI checkpointDataUri*)`

        This email thread
<http://apache-flink-user-mailing-list-archive.2336050.n4.nabble.com/Clarification-on-state-backend-parameters-td11419.html>
explained the first three well. But what's the 4th one for? What's its
difference from others? I'd appreciate your clarification.

       Thanks very much!
Bowen