Collecting system level diagnostics

The following system level diagnostic tables collect system-wide performance information about a cluster:

key_cache

Per node key cache metrics. Equivalent to nodetool info.
net_stats

Per node network information. Equivalent to nodetool netstats.
thread_pool

Per node thread pool active/blocked/pending/completed statistics by pool. Equivalent to nodetool tpstats.
thread_pool_messages

Per node counts of dropped messages by message type. Equivalent to nodetool tpstats.

Procedure

To collect system level data:
Edit the dse.yaml file.
In the dse.yaml file, set the enabled option for cql_system_info_options to true.
```
cql_system_info_options:
    enabled: true
    refresh_rate_ms: 10000
```
(Optional) To control how often the statistics are refreshed, increase or decrease the refresh_rate_ms option in dse.yaml.

The refresh_rate_ms specifies the length of the sampling period, that is, the frequency with which this data is updated.