MySQL Cluster Manager 8.4.6 User Manual
update process [--remove-angel] --pid=os_pidprocess_idcluster_name
This command updates the status of the MySQL NDB Cluster process having
the process ID process_id in the
cluster named cluster_name when the
status of the process is no longer reflected correctly in the
output of the show status
--process command.
This typically happens in the following cases:
The process is a data node configured with
StopOnError=true, so
that it would not be automatically restarted by
mcmd after it has stopped. Instead of
using the start process
command to restart the process, a user might have restarted
the process manually, which would have restored the process
but left mcmd without the knowledge of
the restore. An update
process is then needed to restore the control of
the process by mcmd.
The process is a node that has been stopped by mcmd but, for some reasons, its PID remains valid with the operating system. In some cases, the process might even be running again, without mcmd knowing or being able to control it.
mcmd cannot connect to a
mysqld node due to various reasons (for
example, there are already too many connections to the
node); process status for the node becomes
failed, while the PID file continues to
exist.
When a start
process command for a mysqld
node times out, mcmd looses control of
the node. After fixing the issue on the
mysqld node, run
update process to restore
control of the node by mcmd.
The command works by importing the process into the control of
mcmd again. Checks performed on a process by
mcmd during a cluster import are performed
for the update process command.
Both the process's ID in the cluster
(process_id) and its PID on the
operating system (specified with the
--pid option) are
required. Suppose that the process ID of a data node in the
cluster named mycluster is
3 and its PID on the operating system is
9846, the data node can be updated as shown
here:
mcm> update process --pid=9846 3 mycluster;
+------------------------------+
| Command result |
+------------------------------+
| Process updated successfully |
+------------------------------+
1 row in set (33.07 sec)
For a data node or an SQL node, the command only works if there is at least 1 replica per nodegroup running.
update process supports a
--remove-angel
option, which should be used when updating data nodes: it kills
any running angel
process for a data node and updates its PID file prior to
the actual update; those steps are necessary for the update
process.
Some options, when used to start an applicable NDB node, are not preserved after the update process:
. The same applies now to the