If you have configured your Structured Streaming query to use RocksDB as the state store, you can now get better visibility into the performance of RocksDB, with detailed metrics on get/put latencies, compaction latencies, cache hits, and so on. These metrics are available through the 

StreamingQueryProgress and StreamingQueryListener

 APIs for monitoring a streaming query.

More Info -https://docs.microsoft.com/en-gb/azure/databricks/spark/latest/structured-streaming/production#rocksdb-metrics