Automatic Eviction of Unhealthy Nodes
To decrease the impact of an unhealthy node in your Vertica database, Vertica performs regular health checks. The health checks are performed on a regular schedule. The time between each interval is set by the user using the DatabaseHeartBeatInterval parameter. This parameter specifies the time intervals between internal health checks performed by each node. After a successful health check, the node sends a heartbeat. If a heartbeat is not detected by the time five intervals have elapsed, then the node is evicted from the database cluster.
The formula for the amount of time allowed before an eviction is
TOT = DHBI * 5
where TOT is the total time (in seconds) allowed without a heartbeat before eviction, and DHBI is equal to the value of DatabaseHeartBeatInterval.
By default DatabaseHeartBeatInterval is set to 120, which allows five 120-second intervals to pass without a heartbeat. If you set the DatabaseHeartBeatInterval too low, it can cause evictions in cases of brief node health issues. Sometimes, such premature evictions result in lower availability and performance of the Vertica database.
See Also
DatabaseHeartbeatInterval in General Parameters