CODEWITHSUNDEEP
javatomcatwebsocket
egerardus
egerardus

Reputation: 11486

Are Java websockets supposed to keep threads busy?

I am implementing websockets in Tomcat for an intranet app that has 100 - 200 users on a regular basis.

It is being done to replace a long poll servlet that pushes the same bunch of JSON data I am going to send in on the websocket.

While doing some testing I noticed that every single websocket connection ties up a thread, when I had 50 instances of the app running there were minimally 50 busy threads.

With the long poll servlet I averaged 5 threads with all 50 instances running because the 3.0 servlet spec frees up the thread for long poll servlets.

I know that I can increase the maxThread parameter as needed but I am concerned that if I have a few more apps with the same user base (something that is likely) I am going to require 1000 threads for tomcat that will be busy at all times.

Specifically, my questions about this are:

1) Is this normal? Is there a way of freeing up the websocket thread?

2) Is it actually a problem if I have 1000 threads devoted to keeping websockets open?

3) Should I just stick with long polling until websockets evolve some more?

Tomcat 7.0.50

Java 1.7.0_21

webserver is Windows Server 2008 R2 with 32 GB of RAM - but it is also the database server so that uses up a lot of the memory.

Upvotes: 0

Views: 848

Answers (1)

Thilo
Thilo

Reputation: 262474

To make proper use of websockets, you should also use a non-blocking HTTP connector, otherwise you'll end up with a dedicated thread for each HTTP connection (and that does not scale too well). Check the Tomcat documentation on how to configure that.

Upvotes: 2

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