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From Todd Burruss <bburr...@expedia.com>
Subject ParNew and caching
Date Fri, 18 Nov 2011 00:53:40 GMT
I'm using cassandra 1.0.  Been doing some testing on using cass's cache.  When I turn it on
(using the CLI) I see ParNew jump from 3-4ms to 200-300ms.  This really screws with response
times, which jump from ~25-30ms to 1300+ms.  I've increase new gen and that helps, but still
this is suprising to me, especially since 1.0 defaults to the SerializingCacheProvider –
off heap.

The interesting tid bit is that I have wide rows.  70k+ columns per row, ~50 bytes per column
value.  The cache only must be about 400 rows to catch all the data per node and JMX is reporting
100% cache hits.  Nodetool ring reports < 2gb per node, my heap is 6gb and total RAM is
16gb.

Thoughts?

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