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<refentry id="SQL-PAUSECLUSTER">
<indexterm zone="sql-pausecluster">
<primary>PAUSE CLUSTER</primary>
</indexterm>
<refmeta>
<refentrytitle>PAUSE CLUSTER</refentrytitle>
<manvolnum>7</manvolnum>
<refmiscinfo>SQL - Language Statements</refmiscinfo>
</refmeta>
<refnamediv>
<refname>PAUSE CLUSTER</refname>
<refpurpose>pause the <productname>Postgres-XL</productname> cluster</refpurpose>
</refnamediv>
<refsynopsisdiv>
<synopsis>
PAUSE CLUSTER
</synopsis>
</refsynopsisdiv>
<refsect1>
<title>Description</title>
<para>
<command>PAUSE CLUSTER </command> is a SQL command specific
to <productname>Postgres-XL</productname> that pauses
cluster operation.
</para>
<para>
Pause blocks any new transactions from starting and waits until
existing transactions complete, then returns. Existing sessions
are still connected to Coordinators, it is just that any new statements
will be held up and not be executed.
</para>
<para>
The session that paused the cluster can perform tasks exclusively on the
cluster. This is useful for maintenance tasks to resolve a problem,
restart a Datanode, manually failover a Datanode, etc. Applications will
not receive error messages unless they themselves timeout, statement execution
will just be briefly suspended.
</para>
<para>
Once the DBA has completed whatever tasks were needed, the command <xref linkend="sql-unpausecluster"> can be used.
</para>
</refsect1>
<refsect1>
<title>Compatibility</title>
<para>
<command>PAUSE CLUSTER</command> does not conform to the <acronym>
SQL</acronym> standards, it is a Postgres-XL specific command.
</para>
</refsect1>
</refentry>
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