doc/java-broker/src/docbkx/runtime/Java-Broker-Runtime-Connection-Limit.xml

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<section xmlns="http://docbook.org/ns/docbook" version="5.0" xml:id="Java-Broker-Runtime-Connection-Limit">
  <title>Connection Limits</title>
  <para>
     Each connection to the Broker consumes resources while it is connected. In order to protect
     the Broker against malfunctioning (or malicious) client processes, it is possible to limit the
     number of connections that can be active on any given port.
   </para>
   <para>
       Connection limits on AMQP ports are controlled by an attribute "maxOpenConnections" on
       the port. By default this takes the value of the context variable
       <literal>qpid.port.max_open_connections</literal> which in itself is defaulted to the
       value <literal>-1</literal> meaning there is no limit.
   </para>
   <para>
       If the interpolated value of <literal>maxOpenConnections</literal> on an AMQP port is a
       positive integer, then when that many active connections have been established no new
       connections will be allowed (until an existing connection has been closed). Any such
       rejection of a connection will be accompanied by the operational log message
       <link linkend="Java-Broker-Appendix-Operation-Logging-Message-PRT-1005">PRT-1005</link>.
   </para>
   <para>
       The context variable <literal>qpid.port.open_connections_warn_percent</literal> can be
       used to control when a warning log message is generated as the number of open connections
       approaches the limit for the port. The default value of this variable is
       <literal>80</literal> meaning that if more the number of open connections to the port
       has exceeded 80% of the given limit then the operatinal log message
       <link linkend="Java-Broker-Appendix-Operation-Logging-Message-PRT-1004">PRT-1004</link>
       will be generated.
   </para>
</section>