How to prioritise specific threads in tomcat

I am working on a Java web application for tomcat6 that offers suggest functionality. This means a user types in a free text and get suggestions for completing his input. It is essential that the web application needs to react very fast to make sense.

This web application makes suggestions for data that can be modified at any time. If new data is available the suggest index will be created completely new in the background with the help of a daemon thread. If the data preparation process is finished, the old index is thrown away and the new index comes into play. This offers the advantage of no service gaps.

The background process for data preparation costs a lot of CPU power. This causes the service to hang sometimes for more than a seconds, which makes the service less usable and causes a bad user experience.

My first attempt to solve the problem was to pause all background data preparation threads, when a request has to be processed. This attempt narrows the problem a bit, but the service is still not smooth. It is not that the piece of code for generating the suggests itself gets slower, but it seems as if tomcat does not start the thread for the request immediately all the time because of high load in other threads (I guess)

I have no idea how to face this problem. Can I interact with the thread 开发者_开发知识库scheduler of tomcat and tell him to force execution of requests? As expected adjusting the thread priority also did not help. I did not find configuration options for tomcat that offer help. Or is there no way to deal with this and I have to modify the software concept? I am helpless. Do you have any hints for my how to face this problem?

JanP

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I would not change the thread priority, By doing that you are slowing down other Threads and will slow down other users. If you have synchronized data then you will run into a priority inversion problem, where your faster threads are waiting on lower priority threads to release locks on data.

Instead I would look at how to optimize the data generation process. What are you doing there ?

EDIT:

You could create an ExecutorService and send messages to it through a Queue like in this example: java thread pool keep running In order to be able to change the Thread priority of the tasks instead of calling ExecutorService pool = Executors.newFixedThreadPool(3); you would create a ThreadFactory and then have the ThreadFactory lower the priority of the Threads, then call ExecutorService pool = Executors.newSingleThreadExecutor(threadFactory);