MySQL Utilities 1.4 Manual  /  ...  /  Section statistics

8.6.9. Section statistics

Connectors and other external entities log any errors while accessing servers so that MySQL Fabric can monitor server health and act accordingly. For example, MySQL Fabric promotes a new master after receiving notifications from the number of clients configured in notification_clients) within the time interval configured in notification_interval. If a server is considered unstable but it is not a master, it is simply marked as faulty. To avoid making the system unstable, a new master can only be automatically promoted after the failover_interval has been elapsed since the last promotion. In order to ease the adoption of MySQL Fabric, a built-in failure detector is provided. If the failure detector is enabled to monitor a group, a new master is promoted after 3 failed successive attempts to access the current master within the time interval configured in failover_interval. The failure detection routine tries to connect to servers in a group and uses the value configured in detection_timeout as timeout.

prune_time

How often the internal event log is pruned, in seconds and also the age of events in the event log that is used to present statistics.

notifications

Number of issues before the server is considered unstable.

notification_clients

Number of different sources that should report issues on a server before it is considered unstable.

notification_interval

Amount of time in seconds that is used when deciding if a server is unstable. Issues older than this are not considered when deciding.

failover_interval

Minimum time in seconds between subsequent automatic promotions. This parameter is used to prevent the system entering a sequence of promotions that could disable the system.

detections

Number of successive failed attempts to contact the server after which the built-in failure detector considers the server unstable.

detection_timeout

Timeout in seconds used when contacting the server. If the server does not respond within this time period, it is recorded as a failed attempt to contact the server.

prune_time

Maximum age in seconds for reported issues in the error log. Issues older than this are removed from the error log.


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