Page History

...

• type = stream-state-metrics,
• thread-id = [thread ID],
• task-id = [task ID]
• rocksdb-state-id = [store ID]    for key-value stores
• rocksdb-session-state-id = [store ID]    for session stores
• rocksdb-window-state-id = [store ID]    for window stores  

The following metrics will be exposed in the Kafka Streams' metrics

• bytes-written-rate [bytes/s]
• bytes-written-total [bytes]
• bytes-read-rate [bytes/s]
• bytes-read-total [bytes]
• memtable-bytes-flushed-rate [bytes/s]
• memtable-bytes-flushed-total [bytes]
• memtable-flush-time-(avg|min|max) [ms]
• memtable-hit-rate
• block-cache-data-hit-rate
• block-cache-index-hit-rate
• block-cache-filter-hit-rate
• bytes-read-compaction-rate [bytes/s]
• bytes-written-compaction-rate [bytes/s]
• compaction-time-(avg|min|max) [ms]
• write-stall-duration-(avg|total) [ms]
• num-open-files
• num-file-errors-total

...

Analogously to bytes-written-(rate|total), these metrics measure the bytes read from a RocksDB instance. The metrics show the read load on a RockDB instance.

memtable-bytes-flushed-(rate|total) and memtable-flush-time-(avg|min|max)

When data is put into RocksDB, the data is written into a in-memory tree data structure called memtable. When the memtable is almost full, data in the memtable is flushed to disk by a background process. Metrics bytes-flushed-(rate|total) measure the average throughput of flushes and the total amount of bytes written to disk. Metrics flush-time-(avg|min|max) measure the processing time of flushes. 

...