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ATTACH LEAF
Attaches a detached leaf into the cluster, re-introducing its data (if possible).
Syntax
ATTACH LEAF 'host':port [FORCE] [NO REBALANCE]
Remarks
ATTACH LEAF
will transition the leaf from thedetached
state to theonline
state.ATTACH
is used to reintroduce a leaf back into the system. By default,ATTACH LEAF
also performs any rebalance and resyncing actions needed to bring the leaf up to date with the rest of the cluster. To attach a leaf without rebalancing partitions, use theNO REBALANCE
option. For more information see REBALANCE PARTITIONS .ATTACH LEAF
can only be run on leaf nodes that are present inSHOW_LEAVES
.- This command must be run on the master aggregator node (see Node Requirements for MemSQL Commands ).
- The
FORCE
flag overrides any conflicts that would preventATTACH LEAF
from running. In practice, this happens when the data on the leaf has diverged away from the current state of the cluster (for example, a database was recreated while the leaf was down). You do not need toATTACH LEAF ... FORCE
by default.ATTACH LEAF
without theFORCE
flag collects information about which databases on the leaf are conflicting and the error message indicates directly that you should add theFORCE
flag. By specifying theFORCE
flag, you enableATTACH LEAF
to ignore the conflicting data on the node you are attaching. TheFORCE
flag does not drop the conflicting databases on the node. You can also manually resolve these conflicts by connecting to the leaf directly, examining the conflicting databases, and dropping them if they are no longer relevant. - If you want to reattach many leaves at one time, after restarting a cluster, for example, you can use ATTACH LEAF ALL.
- Detached leaves automatically reattach. To disable this feature, set the global variable
auto_attach
tofalse
. For more information see SET GLOBAL .
Example
memsql> ATTACH LEAF '192.168.1.110':3306;
Query OK, 1 row affected (1.11 sec)
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