CODEWITHSUNDEEP
javatomcat
heiwil
heiwil

Reputation: 669

How to get maxConnections of an application running on Apache Tomcat

I implemented a HttpSessionListener which counts the active sessions of our JSF WebApp. That works fine.

Is there a way to find out how many connections are allowed? Our JSF-WebApp is running on several tomcats with different settings.

What I need is a java method, that returns the max allowed connections of the environment to be able to show a warning if the conecctions may run out.

Any ideas?

Thanks a lot

Upvotes: 0

Views: 709

Answers (1)

Olaf Kock
Olaf Kock

Reputation: 48057

Feels like you should rather configure this in your monitoring environment, e.g. monitoring JMX.

The maximum number of connections (something completely different from number of sessions) can be configured in server.xml - check maxConnections:

The maximum number of connections that the server will accept and process at any given time. When this number has been reached, the server will accept, but not process, one further connection. This additional connection be blocked until the number of connections being processed falls below maxConnections at which point the server will start accepting and processing new connections again. Note that once the limit has been reached, the operating system may still accept connections based on the acceptCount setting. The default value is 8192.

For NIO/NIO2 only, setting the value to -1, will disable the maxConnections feature and connections will not be counted.

What you see here is that it's not only dependent on tomcat, but also on your Operating System. And, of course, on your application: It might fold a lot earlier than that number.

I consider a system that just monitors the number of connections, not the other resources, to not be well tuned: If you figure out that your maximum configured connections are saturated, but technically you could "survive" twice as many: Who configured it? If your page load time goes down below the acceptable time at half of the connections: Who cares about the number of connections available still?

And if a reverse proxy comes in, that could queue some additional connections as well...

To come back to your original question: JMX might be a solution (find the relevant bean). Or, if you want to go homegrown, a servlet filter can keep track of the number of currently handled requests.

Upvotes: 1

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