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Lock Cluster With.En

docs/document/content/user-manual/shardingsphere-proxy/distsql/syntax/ral/lock-cluster-with.en.md

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+++ title = "LOCK CLUSTER WITH" weight = 16 +++

Description

The LOCK CLUSTER WITH syntax is utilized to apply a lock with a specific algorithm to the CLUSTER.

Syntax

{{< tabs >}} {{% tab name="Grammar" %}}

sql
LockClusterWith ::=
  'LOCK' 'CLUSTER' 'WITH' lockStrategy ('TIMEOUT' timeoutMillis)?

timeoutmillis ::=
  long

{{% /tab %}} {{% tab name="Railroad diagram" %}}

<iframe frameborder="0" name="diagram" id="diagram" width="100%" height="100%"></iframe>{{% /tab %}}{{< /tabs >}}

Supplement

  • When the CLUSTER is already locked, it is impossible to re-lock it, otherwise an exception will be thrown.
  • Currently, the lockStrategy supports two lock strategies, namely the exclusive lock WRITE and the read-write lock READ_WRITE .
  • The timeoutMillis is used to indicate the timeout period for attempting to acquire the lock, with the unit being milliseconds. When not specified, the default value is 3,000 milliseconds.

Example

  • Lock the CLUSTER with an exclusive lock without setting the timeout.
sql
LOCK CLUSTER WITH WRITE;
  • Lock the CLUSTER with a read-write lock and set the timeout to 2000 milliseconds.
sql
LOCK CLUSTER WITH READ_WRITE TIMEOUT 2000;

Reserved words

LOCK,CLUSTER,WITH