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From Alain RODRIGUEZ <arodr...@gmail.com>
Subject Re: About the heap
Date Wed, 13 Mar 2013 18:28:28 GMT
"called index_interval set to 128"

I think this is for BloomFilters actually.


2013/3/13 Hiller, Dean <Dean.Hiller@nrel.gov>

> Going to 1.2.2 helped us quite a bit as well as turning on LCS from STCS
> which gave us smaller bloomfilters.
>
> As far as key cache.  There is an entry in cassandra.yaml called
> index_interval set to 128.  I am not sure if that is related to key_cache.
>  I think it is.  By turning that to 512 or maybe even 1024, you will
> consume less ram there as well though I ran this test in QA and my key
> cache size stayed the same so I am really not sure(I am actually checking
> out cassandra code now to dig a little deeper into this property.
>
> Dean
>
> From: Alain RODRIGUEZ <arodrime@gmail.com<mailto:arodrime@gmail.com>>
> Reply-To: "user@cassandra.apache.org<mailto:user@cassandra.apache.org>" <
> user@cassandra.apache.org<mailto:user@cassandra.apache.org>>
> Date: Wednesday, March 13, 2013 10:11 AM
> To: "user@cassandra.apache.org<mailto:user@cassandra.apache.org>" <
> user@cassandra.apache.org<mailto:user@cassandra.apache.org>>
> Subject: About the heap
>
> Hi,
>
> I would like to know everything that is in the heap.
>
> We are here speaking of C*1.1.6
>
> Theory :
>
> - Memtable (1024 MB)
> - Key Cache (100 MB)
> - Row Cache (disabled, and serialized with JNA activated anyway, so should
> be off-heap)
> - BloomFilters (about 1,03 GB - from cfstats, adding all the "Bloom Filter
> Space Used" and considering they are showed in Bytes - 1103765112)
> - Anything else ?
>
> So my heap should be fluctuating between 1,15 GB and 2.15 GB and growing
> slowly (from the new BF of my new data).
>
> My heap is actually changing from 3-4 GB to 6 GB and sometimes growing to
> the max 8 GB (crashing the node).
>
> Because of this I have an unstable cluster and have no other choice than
> use Amazon EC2 xLarge instances when we would rather use twice more EC2
> Large nodes.
>
> What am I missing ?
>
> Practice :
>
> Is there a way not inducing any load and easy to do to dump the heap to
> analyse it with MAT (or anything else that you could advice) ?
>
> Alain
>

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