Thread pool metrics (TPstats) are associated with each stage in Cassandra’s Staged Event-Driven Architecture (SEDA). On the console they can be found as metrics within the Internal Tasks metric group. Explanations on the seven related metrics are listed below:
Table of Contents
The Read Stage metric represents Cassandra conducting reads from the local disk or cache. It helps to diagnose cluster over-stressing, poor system tuning, and hardware issues.
Counter Mutation Stage
The Counter Mutation Stage metric is responsible for counter writes.
View Mutation Stage
The View Mutation Stage metric is responsible for materialised view writes.
The Mutation Stage metric represents all other writes. It is similar to Read Stage, in that it writes related metrics to help diagnose over-stressing, poor system tuning, and hardware issues.
Native Transport Request
The Native Transport Request metric represents client CQL requests. If the requests are blocked by other Cassandra operations, this metric will display the abnormal values.
The Dropped Messages metric represents the total number of dropped messages from all stages in the SEDA.