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From Rob Coli <>
Subject Re: Off-heap row cache and mmapped sstables
Date Mon, 16 Apr 2012 19:19:22 GMT
On 4/12/12, Omid Aladini <> wrote:
> Cassandra issues an mlockall [1] before mmap-ing sstables to prevent
> the kernel from paging out heap space in favor of memory-mapped
> sstables. I was wondering, what happens to the off-heap row cache
> (saved or unsaved)? Is it possible that the kernel pages out off-heap
> row cache in favor of resident mmap-ed sstable pages?

For what it's worth, I find this conjecture plausible given my
understanding of the Cassandra ticket which resulted in the use of
JNA+mlockall. I'd love to hear an opinion from someone from the
project with more in-depth knowledge. :)


=Robert Coli
YAHOO - rcoli.palominob
SKYPE - rcoli_palominodb

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