ActiveMq: Exceeded the maximum number of allowed client connections

Question

In my .Net application all components are interacting with ActiveMQ but after processing few messages, it starts giving error:

"Could not accept connection : org.apache.activemq.transport.tcp.ExceededMaximumConnectionsException: Exceeded the maximum number of allowed client connections.".

I have increased maximum number of connection in web config but its not working. I heard that for this scenario you should use PooledConnectionFactory. Can you guys please suggest how we can implement PooledConnectionFactory or is there any other alternative of it.

Thanks in Advance !!

Answer 1

First of all you can configure how many connections the broker will accept in the brokers transport connector configuration, e.g. in your activemq.xml

<transportConnectors>
  <transportConnector name="openwire" uri="tcp://0.0.0.0:61616?maximumConnections=1000"/>
</transportConnectors>

1000 connections should be the default limit configured in the Apache distribution of ActiveMQ. Unless you have an unexpectedly low limit you are probably leaking connections in your client application, which should be easy to verify using commands like netstat.

I am not the ActiveMQ NMS expert but to my knowledge there is no PooledConnectionFactory for .NET

http://activemq.apache.org/nms/msdoc/1.6.0/vs2005/Output/html/N_Apache_NMS.htm

This is only available for Java. The previous reply is right, you should try to re-use existing connections into the broker. Connection creation is considered a heavy operation. Re-creating connections each time is an anti-pattern and leaking connections would of course be a bug.

Answer 2

Try reuse your Connection somehow when producing messages. Like, keep an open connection around rather than open/close for each message.

There is a CachingConnectionFactory provided in Spring.NET that may simplify this task.