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From graham sanderson <gra...@vast.com>
Subject Re: Things that are about 1M big
Date Sat, 17 May 2014 02:37:29 GMT
Excellent - thank you… 

On May 16, 2014, at 7:08 AM, Samuel CARRIERE <samuel.carriere@urssaf.fr> wrote:

> Hi,
> This is arena allocation of memtables. See here for more infos : 
> http://www.datastax.com/dev/blog/whats-new-in-cassandra-1-0-performance
> 
> 
> 
> 
> De :    graham sanderson <graham@vast.com>
> A :     dev@cassandra.apache.org, 
> Date :  16/05/2014 14:03
> Objet : Things that are about 1M big
> 
> 
> 
> So just throwing this out there for those for whom this might ring a bell.
> 
> I?m debugging some CMS memory fragmentation issues on 2.0.5 - and 
> interestingly enough most of the objects giving us promotion failures are 
> of size 131074 (dwords) - GC logging obviously doesn?t say what those are, 
> but I?d wager money they are either 1M big byte arrays, or less likely 
> 256k entry object arrays backing large maps
> 
> So not strictly critical to solving my problem, but I was wondering if 
> anyone can think of any heap allocated C* objects which are (with no 
> significant changes to standard cassandra config) allocated in 1M chunks. 
> (It would save me scouring the code, or a 9 gig heap dump if I need to 
> figure it out!)
> 
> Thanks,
> 
> Graham


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