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From Jonathan Ellis <jbel...@gmail.com>
Subject Re: Increase flush writer queue
Date Mon, 14 Mar 2011 19:51:35 GMT
Sure, that should be fine.

On Mon, Mar 14, 2011 at 1:03 PM, Daniel Doubleday
<daniel.doubleday@gmx.net> wrote:
> Hi all,
>
> on 0.6:
>
> we are facing increased write latencies every now and then when an unfortunate write
command thread becomes the flush writer for a mem table because of an already running mem
table flush.
>
> I was thinking of setting the work queue in CFS.flushWriterPool to
>
> new LinkedBlockingQueue<Runnable>(3) // because 3 is my favorite number
>
> instead of
>
> new LinkedBlockingQueue<Runnable>(DatabaseDescriptor.getAllDataFileLocations().length)
>
> while leaving the max threads at 1 (we have only one date dir)
>
> I'm not afraid to OOM. We have enough heap to hold the extra 2 mem tables.
>
> Anybody did this and got in trouble?
>
> PS: I know that 0.7 makes this configurable (but also increases writer concurrency while
I would rather only queue).
>
> Thanks,
> Daniel



-- 
Jonathan Ellis
Project Chair, Apache Cassandra
co-founder of DataStax, the source for professional Cassandra support
http://www.datastax.com

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