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From Ryan King <r...@twitter.com>
Subject Re: Memory usage continually increases with reads
Date Wed, 28 Apr 2010 19:28:01 GMT
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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