On 07/28/09 17:16, Scott Oaks wrote:
>
>>> I was wondering about thread pools, actually. I see there are by
>>> default 2 created: http-thread-pool with a limit on the number of
>>> threads in the queue and a small max pool size, and thread-pool-1
>>> with no limit on the queue threads and a large max pool size. The 3
>>> default network listeners all use http-thread-pool. Under what
>>> circumstances might a user specify the other one?
>> One I can think of off hand is if you had an app that you knew would
>> keep connections open for long time for something like feeding very
>> large files/streams back to the client. In this case you might want a
>> separate thread pool to handle that kind of load. But I'd profile
>> first to make sure. The grizzly subsystem uses NIO to handle that
>> processing so is fairly efficient at handling a large number of
>> connections.
> But the defaults are also different. Typically, the small thread pool is
> the default threadpool used by HTTP requests. We have discussions about
> this all the time, but the default HTTP threadpool (at least right now)
> is sized for a developer machine (1-2 cpus/cores) that is running web
> apps that don't block very often and is hence sized with a default
> maximum of 5.
>
> The large thread pool is the default threadpool for RMI/IIOP requests.
> It is much bigger by default: those requests are longer running,
> typically access a blocking back-end resources, and are more frequently
> used by larger configurations. Also, in earlier versions of the
> appserver, IIOP didn't use grizzly or NIO and hence needed a bigger
> threadpool.
>
> Both need to be tuned according to application needs and hardware.
Thanks very much for this info. I can mention it briefly in the Admin
Console help, but it seems like the Admin Guide would be a good place to
put more information about tuning if you have it.
Kim
>
> -Scott
>
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