REMOVE LEAF

Removes a leaf node from a cluster without deleting its data.
This command rebalances the leaf node’s partitions into the remaining cluster, removes the specified leaf node from the Master Aggregator, and the leaf node will be removed from the SHOW LEAVES command.
While the cluster will no longer know about this leaf node, Toolbox will still know that memsqlctl recognizes that there is a running memsql process which is now in the unknown state.
A leaf node that has been removed can be added back to the cluster, without any loss of data, by using the ADD LEAF command.
This command causes implicit commits. Refer to COMMIT for more information.
Refer to sdb-admin delete-node to delete a leaf node and its data.
Refer to the Permission Matrix for the required permission.

Syntax

REMOVE LEAF 'host':port [FORCE] [KILL] [ENSURE_PARTITION_SAFETY]

Port value is 3306.
If the leaf does not have a pair, SingleStore will rebalance its partitions onto the remaining leaves before removing it. After this rebalance process is over, the partition databases that were moved are no longer present on the node.
You must use the ADD LEAF command if you want to reintroduce the removed leaf into the system.
This command can be run on the master aggregator node, or a child aggregator node (see Node Requirements for SingleStore Commands ).
The FORCE flag disables the rebalancing behavior of REMOVE LEAF. This behavior is designed to keep the database online while you remove a leaf from the system. However, if you are performing maintenance and want to quickly remove a leaf node without keeping the database online, then use the FORCE flag to disable automatic rebalancing.
KILL prevents persistent long running write queries from blocking a clustering option for an arbitrarily long time (for example, a scale up or scale down or even an upgrade). Auto-rebalances automatically use the KILL mode if the auto-rebalance fails to run after three attempts.
ENSURE_PARTITION_SAFETY prevents a leaf (or leaves) from being removed if it contains the last online instance of a partition.
If MemSQL Ops is not enabled for manual cluster control, then a REMOVE LEAF can result in the leaf being added back without user intervention.

SQL

REMOVE LEAF '192.168.1.110':3306;

Removes all leaf nodes without removing the data.

See REMOVE LEAF section above for further information.

SQL

REMOVE LEAVES [IF EXISTS] ('host_1':port_1, ..., 'host_n':port_n) [FORCE] [ENSURE_PARTITION_SAFETY]

REMOVE LEAVES is an all-or-nothing command either all the leaves will be removed, or none of them will.

SQL

REMOVE LEAVES ('192.168.1.110':3306, '192.168.1.111':3306, '192.168.1.112':3306);