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From Jason Harvey <alie...@gmail.com>
Subject Re: Bizarre side-effect of increasing read concurrency
Date Sat, 02 Apr 2011 23:03:46 GMT
My Xmx and Xms are both 7.5GB. However, I never see the heap usage
reach past 5.5. Think it is still a good idea to increase the heap?

Thanks,
Jason

On Apr 2, 2:45 am, Peter Schuller <peter.schul...@infidyne.com> wrote:
> > Previously, mark-and-sweep would run around 5.5GB, and would cut heap
> > usage to 4GB. Now, it still runs at 5.5GB, but it shrinks all the way
> > down to 2GB used. This behavior was consistent in every machine I
> > increased read-concurrent on.
>
> So each full CMS cycles brings it down to 4 on a maximum heap size of
> 5.5GB? Or are you using VM options such that Xms != Xmx?
>
> If 5.5 is the maximum heap size and you're at 4 gig after the
> completion of a mark-and-sweep, I'd say it would be a good idea to
> pre-emptively up the heap size a bit (or decreases memtables/key/row
> caches).
>
> --
> / Peter Schuller

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