Table statistics
Compaction metrics provide a number of statistics that are important for monitoring performance trends.
For individual tables, ColumnFamilyStoreMBean provides the same general latency attributes as
StorageProxyMBean. Unlike StorageProxyMBean, ColumnFamilyStoreMBean has a number of other
statistics that are important to monitor for performance trends. The most important of these
are:
| Attribute | Description |
|---|---|
| MemtableDataSize | The total size consumed by this table's data (not including metadata). |
| MemtableColumnsCount | Returns the total number of columns present in the memtable (across all keys). |
| MemtableSwitchCount | How many times the memtable has been flushed out. |
| RecentReadLatencyMicros | The average read latency since the last call to this bean. |
| RecentWriterLatencyMicros | The average write latency since the last call to this bean. |
| LiveSSTableCount | The number of live SSTables for this table. |
The recent read latency and write latency counters are important in making sure operations are happening in a consistent manner. If these counters start to increase after a period of staying flat, you probably need to add capacity to the cluster.
You can set a threshold and monitor LiveSSTableCount to ensure that the number of SSTable for a given table does not become too great.