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From Jonathan Ellis <jbel...@gmail.com>
Subject Re: Indexes on heterogeneous rows
Date Mon, 18 Apr 2011 02:25:21 GMT
Right.

On Sun, Apr 17, 2011 at 4:23 AM, David Boxenhorn <david@taotown.com> wrote:
> Thanks, Jonathan. I think I understand now.
>
> To sum up: Everything would work, but if your only equality is on "type"
> (all the rest inequalities), it could be very inefficient.
>
> Is that right?
>
> On Thu, Apr 14, 2011 at 7:22 PM, Jonathan Ellis <jbellis@gmail.com> wrote:
>>
>> On Thu, Apr 14, 2011 at 6:48 AM, David Boxenhorn <david@taotown.com>
>> wrote:
>> > The reason why I put "type" first is that queries on type will
>> > always be an exact match, whereas the other clauses might be
>> > inequalities.
>>
>> Expression order doesn't matter, but as you imply, non-equalities
>> can't be used in an index lookup and have to be checked in a nested
>> loop phase afterwards.
>>
>> --
>> 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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