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From Tyler Hobbs <ty...@datastax.com>
Subject Re: Secondary Index Limitation / DOes it exist in Cassandra 1.1.2
Date Wed, 01 Aug 2012 02:38:24 GMT
That's only a small part of the problem.  A larger issue is that what
follows the index read is basically a multiget within that node, which
generates a lot of non-sequential I/O.  The second issue is that nodes are
queried sequentially to get more result rows until the requested row count
has been reached.  So, if each node only has a handful of matching rows,
you'll end up querying every node in the cluster (more or less) to answer
the query.

On Tue, Jul 31, 2012 at 8:44 PM, Arya Goudarzi <goudarzi@gmail.com> wrote:

> I know that secondary indexes are stored
> to local column families on each node. Previously where the default
> cache key value was 200,000 rows, and you couldn't really tune the
> local index column family, that posed a limitation on low cardinality
> of the possible values of the secondary index column. However, in
> Cassandra 1.1.2, I don't see the option of tuning cache per row count
> any more and it is solely memory based. I wonder if this eliminates he
> previous limitations with secondary indexes.
>



-- 
Tyler Hobbs
DataStax <http://datastax.com/>

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