update process [--remove-angel] --pid=os_pidprocess_idcluster_name This command updates the status of the MySQL NDB Cluster process having the process IDprocess_id in the cluster namedcluster_name when the status of the process is no longer reflected correctly in the output of theshow 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 bymcmd after it has stopped. Instead of using thestart processcommand to restart the process, a user might have restarted the process manually, which would have restored the process but leftmcmd without the knowledge of the restore. Anupdate processis then needed to restore the control of the process bymcmd.The process is a node that has been stopped bymcmd but, for some reasons, its PID remains valid with the operating system. In some cases, the process might even be running again, withoutmcmd knowing or being able to control it.
mcmd cannot connect to amysqld 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 processcommand for amysqld node times out,mcmd looses control of the node. After fixing the issue on themysqld node, runupdate processto restore control of the node bymcmd.
The command works by importing the process into the control ofmcmd again. Checks performed on a process bymcmd during a cluster import are performed for theupdate 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 namedmycluster is3 and its PID on the operating system is9846, 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 runningangel 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