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From Robert Coli <rc...@eventbrite.com>
Subject Re: Turn off compression (1.2.11)
Date Tue, 18 Feb 2014 19:23:52 GMT
On Mon, Feb 17, 2014 at 4:35 PM, Plotnik, Alexey <aplotnik@rhonda.ru> wrote:

> After analyzing Heap I saw this buffer has a size about 70KB per SSTable.
> I have more than 30K SSTables per node.
>

I'm thinking your problem is not compression, it's using the old 5mb
default for Level Compaction and having 30,000 SSTables as a result.

Before turning off compression, I suggest :

1) change level SSTable size to the new default, 160mb
2) force all SSTables to L0 (in 1.2, this means removing their .json files
with the node down, IIRC)
3) watch level compaction run for a long time, reducing the number of
SSTables you have

As an aside, 1.2.0 beta moved a bunch of data related to compression off
the heap. If you were to try to run the same cluster under 1.1, you'd
probably OOM your heap immediately.

https://issues.apache.org/jira/browse/CASSANDRA-4941

=Rob

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