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From aaron morton <aa...@thelastpickle.com>
Subject Re: Why the StageManager thread pools have 60 seconds keepalive time?
Date Thu, 16 Aug 2012 23:22:09 GMT
That's some pretty old code. I would guess it was done that way to conserve resources. And
_i think_ thread creation is pretty light weight.

Jonathan / Brandon / others - opinions ? 

Cheers


-----------------
Aaron Morton
Freelance Developer
@aaronmorton
http://www.thelastpickle.com

On 17/08/2012, at 8:09 AM, Guillermo Winkler <gwinkler@inconcertcc.com> wrote:

> Hi, I have a cassandra cluster where I'm seeing a lot of thread trashing from the mutation
pool.
> 
> MutationStage:72031
> 
> Where threads get created and disposed in 100's batches every few minutes, since it's
a 16 core server concurrent_writes is set in 100 in the cassandra.yaml. 
> 
> concurrent_writes: 100
> 
> I've seen in the StageManager class this pools get created with 60 seconds keepalive
time.
> 
> DebuggableThreadPoolExecutor -> allowCoreThreadTimeOut(true);
> 
> StageManager-> public static final long KEEPALIVE = 60; // seconds to keep "extra"
threads alive for when idle
> 
> Is it a reason for it to be this way? 
> 
> Why not have a fixed size pool with Integer.MAX_VALUE as keepalive since corePoolSize
and maxPoolSize are set at the same size?
> 
> Thanks,
> Guille
> 


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