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From Jonathan Ellis <jbel...@gmail.com>
Subject Re: customizable size tiered compaction
Date Sat, 22 Sep 2012 14:01:29 GMT
It's a compaction strategy option, so it's cluster-wide for that strategy.

On Sat, Sep 22, 2012 at 5:46 AM, Radim Kolar <hsn@filez.com> wrote:
> I am interested in experiments with size tiered compaction, because i get
> sstables which are never compacted because no other sstable is close to
> their size, i have plans to experiment with bucket ratio which is currently
> 50-150 percent to make it 33-200 percent.
>
> Its all about changing constants at lines 170-171
>
> https://github.com/apache/cassandra/blob/trunk/src/java/org/apache/cassandra/db/compaction/SizeTieredCompactionStrategy.java
>
> if ((size > (oldAverageSize / 2) && size < (3 * oldAverageSize) / 2)
>
> || (size < minSSTableSize && oldAverageSize < minSSTableSize))
>
> to make these constant configurable, i suppose something similar to
> "min_sstable_size" is needed. Its min_sstable_size configurable by CF or its
> node wide setup?



-- 
Jonathan Ellis
Project Chair, Apache Cassandra
co-founder of DataStax, the source for professional Cassandra support
http://www.datastax.com

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