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From Nathan McCall <n...@vervewireless.com>
Subject Re: cassandra not responding
Date Tue, 16 Mar 2010 20:32:22 GMT
The cache is a "second-chance FIFO" from this library:
http://code.google.com/p/concurrentlinkedhashmap/source/browse/trunk/src/java/com/reardencommerce/kernel/collections/shared/evictable/ConcurrentLinkedHashMap.java

That sounds like an awful lot of churn given the size of the queue and
the number of references it might keep for the second-chance stuff.
How big of a hot data set do you need to maintain? The amount of
overhead for such a large record set may not buy you anything over
just relying on the file system cache and turning down the heap size.

-Nate

On Tue, Mar 16, 2010 at 1:17 PM, B. Todd Burruss <bburruss@real.com> wrote:
> i think i better make sure i understand how the row/key cache works.  i
> currently have both set to 10%.  so if cassandra needs to read data from an
> sstable that has 100 million rows, it will cache 10,000,000 rows of data
> from that sstable?  so if my row is ~4k, then we're looking at ~40gb used by
> cache?
>

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