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From Pid <>
Subject Re: Connector Setting Problem in tomcat 6.0.29
Date Sun, 07 Nov 2010 12:29:44 GMT
On 07/11/2010 01:27, Jim Riggs wrote:
> On Nov 6, 2010, at 2:17 PM, Christopher Schultz wrote:
>>> I believe (if I heard it correctly), either Mark T. or Tim F.
>>> explained at ApacheCon this week that the minimum is not immediate.
>>> It needs to build up to that level.  So, when you start Tomcat, you
>>> won't immediately fire up 150 threads for the executor pool, but once
>>>> = 150 threads are created in the process of serving requests, it
>>> will always keep a minimum of 150 for you.
>> If that's the case, I find that surprising. I always like to avoid
>> violating the principle of least surprise. minSpareThreads as a name
>> implies to me that those spares are /always/ available, even immediately
>> after startup.
> Chris -
> If you look in org.apache.catalina.core.StandardThreadExecutor, you will see that it
is using a ThreadPoolExecutor.  setMinSpareThreads() calls setCorePoolSize() in the ThreadPoolExecutor.
 If you read the javadoc for ThreadPoolExecutor, specifically the subsections labeled "Core
and maximum pool sizes" and "On-demand construction", you will see that the threads are created
on demand unless you use prestartCoreThread()/prestartAllCoreThreads(), which Tomcat does
> So, although it may seem surprising or even counterintuitive, all 150 will not be fired
up on startup.  Perhaps we could add a separate attribute on the Executor (e.g. startThreads)?
 Then Tomcat would have a paradigm similar to httpd's Start(Servers|Threads) and MinSpare(Servers|Threads).
 Any interest in such an attribute?  It would be fairly simple to roll a patch for it...

Making this less surprising and adding an attribute to prestart some
threads would be a good idea IMHO.


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