17.5.6.1 MySQL Cluster Logging Management Commands

ndb_mgm supports a number of management commands related to the cluster log. In the listing that follows, node_id denotes either a database node ID or the keyword ALL, which indicates that the command should be applied to all of the cluster's data nodes.

The following table describes the default setting (for all data nodes) of the cluster log category threshold. If an event has a priority with a value lower than or equal to the priority threshold, it is reported in the cluster log.

Note that events are reported per data node, and that the threshold can be set to different values on different nodes.

CategoryDefault threshold (All data nodes)
STARTUP7
SHUTDOWN7
STATISTICS7
CHECKPOINT7
NODERESTART7
CONNECTION7
ERROR15
INFO7

The STATISTICS category can provide a great deal of useful data. See Section 17.5.6.3, “Using CLUSTERLOG STATISTICS in the MySQL Cluster Management Client”, for more information.

Thresholds are used to filter events within each category. For example, a STARTUP event with a priority of 3 is not logged unless the threshold for STARTUP is set to 3 or higher. Only events with priority 3 or lower are sent if the threshold is 3.

The following table shows the event severity levels.

Note

These correspond to Unix syslog levels, except for LOG_EMERG and LOG_NOTICE, which are not used or mapped.

Severity Level Value

Severity

Description

1

ALERT

A condition that should be corrected immediately, such as a corrupted system database

2

CRITICALCritical conditions, such as device errors or insufficient resources

3

ERRORConditions that should be corrected, such as configuration errors

4

WARNINGConditions that are not errors, but that might require special handling

5

INFOInformational messages

6

DEBUGDebugging messages used for NDBCLUSTER development

Event severity levels can be turned on or off (using CLUSTERLOG FILTER—see above). If a severity level is turned on, then all events with a priority less than or equal to the category thresholds are logged. If the severity level is turned off then no events belonging to that severity level are logged.

Important

Cluster log levels are set on a per ndb_mgmd, per subscriber basis. This means that, in a MySQL Cluster with multiple management servers, using a CLUSTERLOG command in an instance of ndb_mgm connected to one management server affects only logs generated by that management server but not by any of the others. This also means that, should one of the management servers be restarted, only logs generated by that management server are affected by the resetting of log levels caused by the restart.