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From Kyusik Chung <kyu...@discovereads.com>
Subject Re: Memory usage continually increases with reads
Date Wed, 28 Apr 2010 19:51:44 GMT
Hi Ryan,

Do you mean these settings, or other settings?

<SlicedBufferSizeInKB>64</SlicedBufferSizeInKB>
<FlushDataBufferSizeInMB>32</FlushDataBufferSizeInMB>
<FlushIndexBufferSizeInMB>8</FlushIndexBufferSizeInMB>
<ColumnIndexSizeInKB>64</ColumnIndexSizeInKB>
<MemtableThroughputInMB>64</MemtableThroughputInMB>
<BinaryMemtableThroughputInMB>256</BinaryMemtableThroughputInMB>
<MemtableOperationsInMillions>0.3</MemtableOperationsInMillions>
<MemtableFlushAfterMinutes>60</MemtableFlushAfterMinutes>

Thanks!

Kyusik Chung

On Apr 28, 2010, at 12:28 PM, Ryan King wrote:

> On Wed, Apr 28, 2010 at 12:12 PM, Kyusik Chung <kyusik@discovereads.com> wrote:
>> Hello.  I am using Cassandra 0.6.1 on ubuntu 8.04.  3 node cluster.
>> 
>> I notice that when I start making lots of read requests (serially), memory usage
of jsvc keeps climbing until it uses up all memory on the server (happens for all 3 servers
in the cluster).  At that point, the box starts swapping a little (but not too much) and performance
is degraded.  Read performance does not drop off a cliff, but it does take a serious hit (maybe
50%).
>> 
>> I have tried setting Xmx to various different values, but it doesnt seem to limit
the growth in memory usage.  I understand that I should expect to see jsvc use a bit more
memory than what the jvm is configured to use, but it doesnt seem to be limited to just an
overhead.  I have set Xmx all the way down to 128M (just to test) and still jsvc will use
up 2G of memory.
>> 
>> Are there other settings that I should be changing?
>> 
>> Note that when I test by simply running a lot of writes but no reads, jsvc seems
to respect the Xmx value.
> 
> What are you cache settings?
> 
> -ryan


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