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From Jonathan Ellis <jbel...@gmail.com>
Subject Re: Choice of Index
Date Wed, 11 May 2011 20:31:24 GMT
No, Cassandra uses statistics to see which index will result in less
rows to check.

On Wed, May 11, 2011 at 12:42 PM, Baskar Duraikannu
<baskar.duraikannu.db@gmail.com> wrote:
> Hello -
> I am using 0.8 Beta 2 and have a CF containing COMPANY, ACCOUNTNUMBER and
> some account related data.  I have index on both Company and AccountNumber.
> If I run a query -
>
> SELECT <DATA> FROM COMPANYCF WHERE COMPANY='XXX' AND ACCOUNTNUMBER = 'YYY'
>
> Even though ACCOUNTNUMBER based Index is a better index to use for the above
> query compared to COMPANY based Index, Cassandra seems to pick COMPANY
> index.
> Does Cassandra always uses Index on first "where" clause?
> I can always change the above query to have account number as the first
> "where" clause.
> Just wanted to understand whether any kind of index optimization built into
> Cassandra 0.8.
> Thanks
> Baskar Duraikannu
>
>
>



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

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