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From Jonathan Ellis <jbel...@gmail.com>
Subject Re: IndexInterval Tuning
Date Tue, 05 Apr 2011 13:57:45 GMT
On Tue, Apr 5, 2011 at 8:54 AM, Jonathan Ellis <jbellis@gmail.com> wrote:
> Adjusting indexinterval is unlikely to be useful on very narrow rows.
> (Its purpose is to make random access to _large_ rows doable.)

Whoops, that's column_index_size_in_kb.

I'd play w/ keycache before index_interval personally.  (If you can
get 100% key cache hit rate it doesn't really matter what index
interval is, as long as you can still build the cache effectively.)

>
> On Mon, Apr 4, 2011 at 8:38 PM, Chris Burroughs
> <chris.burroughs@gmail.com> wrote:
>> I have a case with very narrow rows.  As such I have a large row cache
>> that does nicely handles > 50% of requests.  I think it's likely that
>> the current tradeoff between page cache and row cache is reasonable.
>> Using a key cache doesn't make sense in this instance.  However, a third
>> option is to adjust the IndexInterval [1] [2].
>>
>> It would theoretically be reasonable to:
>>  - Increase the IndexInterval to make more memory available for row or
>> page cache.
>>  - Decrease the IndexInterval for more effective sampling.
>>
>> When the knob could be turned either direction it's hard to know which
>> way to start.
>>
>> Does anyone have any experince succesfully adjusting the IndexInterval
>> for improved performance with narrow rows?
>>
>>
>> [1] https://issues.apache.org/jira/browse/CASSANDRA-1488
>>
>> [2] http://www.datastax.com/dev/blog/whats-new-cassandra-066
>>
>
>
>
> --
> Jonathan Ellis
> Project Chair, Apache Cassandra
> co-founder of DataStax, the source for professional Cassandra support
> http://www.datastax.com
>



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

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