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From Thorsten von Eicken <...@rightscale.com>
Subject Re: how to increase compaction rate?
Date Mon, 12 Mar 2012 06:21:44 GMT
On 3/11/2012 9:17 PM, Peter Schuller wrote:
>> multithreaded_compaction: false
> Set to true.
I did try that. I didn't see it go any faster. The cpu load was lower,
which I assumed meant fewer bytes/sec being compressed
(SnappyCompressor). I didn't see multiple compactions in parallel.
Nodetool compactionstats behaved strange and instead of showing
individual compactions with a %-complete it showed a running count of
total bytes compacted. (Darn, I don't have the output of that anymore in
my terminal buffer.) It just didn't look good to me. Are you positive
that it is faster with leveled compaction? I don't understand why I
don't get multiple concurrent compactions running, that's what would
make the biggest performance difference. Is the compaction parallelism
perhaps only across multiple CFs? That would explain what I see.

Thorsten

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