Dear community, I am studying the behaviour of the Cassandra TimeWindowCompactionStragegy. To do so I am watching some metrics. Two of these metrics are important: Compaction.CompletedTasks, a gauge, and the TotalCompactionsCompleted, a Meter.
According to the documentation ( http://cassandra.apache.org/doc/latest/operating/metrics.html#table-metrics ): Completed Taks = Number of completed compactions since server [re]start. TotalCompactionsCompleted = Throughput of completed compactions since server [re]start. As I realized, the TotalCompactionsCompleted, in the Meter object, has a counter, which I supposed would be numerically close to the CompletedTasks gauge. But they are very different, with the Completed Tasks being much higher than the TotalCompactions Completed. According to the code, in github (class metrics.CompactionMetrics.java): Completed Taks - Number of completed compactions since server [re]start TotalCompactionsCompleted - Total number of compactions since server [re]start Can you help me and explain the difference between these two metrics, as they seem to have very distinct values, with the Completed Tasks being around 1000 times the value of the counter in TotalCompactionsCompleted. Thanks in Advance, Lucas Benevides