customizable size tiered compaction

[Radim Kolar <hs...@filez.com>]

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?

Re: customizable size tiered compaction

[Radim Kolar <hs...@filez.com>]

Dne 22.9.2012 16:01, Jonathan Ellis napsal(a):
> It's a compaction strategy option, so it's cluster-wide for that strategy.
coded in https://issues.apache.org/jira/browse/CASSANDRA-4704

Re: customizable size tiered compaction

[Jonathan Ellis <jb...@gmail.com>]

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 <hs...@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