MySQL 9.4 Reference Manual Including MySQL NDB Cluster 9.4
In this section, we discuss the types of event logs provided by NDB Cluster, and the types of events that are logged.
NDB Cluster provides two types of event log:
The cluster log, which includes events generated by all cluster nodes. The cluster log is the log recommended for most uses because it provides logging information for an entire cluster in a single location.
By default, the cluster log is saved to a file named
ndb_,
(where node_id_cluster.lognode_id is the node ID of
the management server) in the management server's
DataDir.
Cluster logging information can also be sent to
stdout or a syslog
facility in addition to or instead of being saved to a file,
as determined by the values set for the
DataDir and
LogDestination
configuration parameters. See
Section 25.4.3.5, “Defining an NDB Cluster Management Server”, for more
information about these parameters.
Node logs are local to each node.
Output generated by node event logging is written to the file
ndb_
(where node_id_out.lognode_id is the node's
node ID) in the node's
DataDir. Node event
logs are generated for both management nodes and data nodes.
Node logs are intended to be used only during application development, or for debugging application code.
Each reportable event can be distinguished according to three different criteria:
Category: This can be any one of the
following values: STARTUP,
SHUTDOWN, STATISTICS,
CHECKPOINT, NODERESTART,
CONNECTION, ERROR, or
INFO.
Priority: This is represented by one of the numbers from 0 to 15 inclusive, where 0 indicates “most important” and 15 “least important.”
Severity Level: This can be any one of
the following values: ON,
DEBUG, INFO,
WARNING, ERROR,
CRITICAL, ALERT, or
ALL. (This is also sometimes referred to as
the log level.)
The cluster log can be filtered on these properties using the NDB
management client CLUSTERLOG
command. This command affects the cluster log only, and has no
effect on the node logs; debug logging in one or more node logs
can be turned on and off using the ndb_mgm
NODELOG DEBUG command.
The format used in a log message generated by NDB Cluster is as shown here:
timestamp[node_type]level-- Nodenode_id:message
Each line in the log, or log message, contains the following information:
A timestamp in
YYYY-MM-DD
HH:MM:SS
The node_type, or type of node or
application which is performing the logging. In the cluster
log, this is always [MgmSrvr]; in the data
node log, it is always [ndbd].
[NdbApi] and other values are possible in
logs generated by NDB API applications and tools.
The level of the event, sometimes
also referred to as its severity level or log level. See
earlier in this section, as well as
Section 25.6.3.1, “NDB Cluster Logging Management Commands”,
for more information about severity levels.
The ID of the node reporting the event
(node_id).
A message containing a description
of the event. The most common types of events to appear in the
log are connections and disconnections between different nodes
in the cluster, and when checkpoints occur. In some cases, the
description may contain status or other information.
A sample from an actual cluster log is shown here:
2021-06-10 10:01:07 [MgmtSrvr] INFO -- Node 5: Start phase 5 completed (system restart) 2021-06-10 10:01:07 [MgmtSrvr] INFO -- Node 6: Start phase 5 completed (system restart) 2021-06-10 10:01:07 [MgmtSrvr] INFO -- Node 5: Start phase 6 completed (system restart) 2021-06-10 10:01:07 [MgmtSrvr] INFO -- Node 6: Start phase 6 completed (system restart) 2021-06-10 10:01:07 [MgmtSrvr] INFO -- Node 5: President restarts arbitration thread [state=1] 2021-06-10 10:01:07 [MgmtSrvr] INFO -- Node 5: Start phase 7 completed (system restart) 2021-06-10 10:01:07 [MgmtSrvr] INFO -- Node 6: Start phase 7 completed (system restart) 2021-06-10 10:01:07 [MgmtSrvr] INFO -- Node 5: Start phase 8 completed (system restart) 2021-06-10 10:01:07 [MgmtSrvr] INFO -- Node 6: Start phase 8 completed (system restart) 2021-06-10 10:01:07 [MgmtSrvr] INFO -- Node 5: Start phase 9 completed (system restart) 2021-06-10 10:01:07 [MgmtSrvr] INFO -- Node 6: Start phase 9 completed (system restart) 2021-06-10 10:01:07 [MgmtSrvr] INFO -- Node 5: Start phase 50 completed (system restart) 2021-06-10 10:01:07 [MgmtSrvr] INFO -- Node 6: Start phase 50 completed (system restart) 2021-06-10 10:01:07 [MgmtSrvr] INFO -- Node 5: Start phase 101 completed (system restart) 2021-06-10 10:01:07 [MgmtSrvr] INFO -- Node 6: Start phase 101 completed (system restart) 2021-06-10 10:01:07 [MgmtSrvr] INFO -- Node 5: Started (mysql-9.5.0 ndb-9.5.0) 2021-06-10 10:01:07 [MgmtSrvr] INFO -- Node 6: Started (mysql-9.5.0 ndb-9.5.0) 2021-06-10 10:01:07 [MgmtSrvr] INFO -- Node 5: Node 50: API mysql-9.5.0 ndb-9.5.0 2021-06-10 10:01:07 [MgmtSrvr] INFO -- Node 6: Node 50: API mysql-9.5.0 ndb-9.5.0 2021-06-10 10:01:08 [MgmtSrvr] INFO -- Node 6: Prepare arbitrator node 50 [ticket=75fd00010fa8b608] 2021-06-10 10:01:08 [MgmtSrvr] INFO -- Node 5: Started arbitrator node 50 [ticket=75fd00010fa8b608] 2021-06-10 10:01:08 [MgmtSrvr] INFO -- Node 6: Communication to Node 100 opened 2021-06-10 10:01:08 [MgmtSrvr] INFO -- Node 6: Communication to Node 101 opened 2021-06-10 10:01:08 [MgmtSrvr] INFO -- Node 5: Communication to Node 100 opened 2021-06-10 10:01:08 [MgmtSrvr] INFO -- Node 5: Communication to Node 101 opened 2021-06-10 10:01:36 [MgmtSrvr] INFO -- Alloc node id 100 succeeded 2021-06-10 10:01:36 [MgmtSrvr] INFO -- Nodeid 100 allocated for API at 127.0.0.1 2021-06-10 10:01:36 [MgmtSrvr] INFO -- Node 100: mysqld --server-id=1 2021-06-10 10:01:36 [MgmtSrvr] INFO -- Node 5: Node 100 Connected 2021-06-10 10:01:36 [MgmtSrvr] INFO -- Node 6: Node 100 Connected 2021-06-10 10:01:36 [MgmtSrvr] INFO -- Node 5: Node 100: API mysql-9.5.0 ndb-9.5.0 2021-06-10 10:01:36 [MgmtSrvr] INFO -- Node 6: Node 100: API mysql-9.5.0 ndb-9.5.0
For additional information, see Section 25.6.3.2, “NDB Cluster Log Events”.