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Please take a look when the web site performance seems to be slow, to see what your thread usage is. When performance is OK, you may not see a lot of Active Threads, and so will not get the best picture of what needs to be done.
Please go to the HTTP Admin IBM Web Administration interface in your browser (the IBM HTTP Server *ADMIN instance needs to be running):
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On the page that appears, under the General tab, look at Active Threads and Idle Threads. Adding Active and Idle tells the Total threads. The default for Total Threads is 40 (unless it has been changed in CHGHTTPA, see note below). If you have very few idle threads, you may occasionally be running out of threads, which could cause a hang up. You can refresh the screen manually, or set the refresh interval in the Refresh Interval drop down, to watch these statistics for a while and see if the idle threads are very low, or if they ever drop to zero. If so, you can increase the threads using the ThreadsPerChild directive in the Apache configuration to give Apache more threads to work with. The default can be changed in the HTTP Web Admin by going to Advanced -> Settings tab, and adjusting Number of Threads Maximum.
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