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From "Tiwari, Dushyant" <Dushyant.Tiw...@morganstanley.com>
Subject RE: Secondary indexes and cardinality
Date Tue, 14 Feb 2012 05:21:29 GMT
Perfect, Aaron, Thanks a lot



From: aaron morton [mailto:aaron@thelastpickle.com]
Sent: Tuesday, February 14, 2012 12:54 AM
To: user@cassandra.apache.org
Subject: Re: Secondary indexes and cardinality

Heard that indexing a field with high cardinality is not good.
http://www.datastax.com/docs/0.7/data_model/secondary_indexes

Will there be any performance improvement? Is this the way secondary indexes are maintained?
Updating secondary indexes requires a read and a write.

Also this makes me think - Will there be any lose if we have many rows in a CF say 10 million?
http://www.datastax.com/docs/0.7/data_model/cfs_as_indexes#indexes

Having 10 million columns in a row is not a problem by itself. It depends on how you want
to read things.

Cheers

-----------------
Aaron Morton
Freelance Developer
@aaronmorton
http://www.thelastpickle.com

On 14/02/2012, at 1:11 AM, Tiwari, Dushyant wrote:


Hi Cassandra Users,

Heard that indexing a field with high cardinality is not good. If we create a CF to store
the index information like indexed field as key and the keys of original CF as cols in the
row. Will there be any performance improvement? Is this the way secondary indexes are maintained?

Also this makes me think - Will there be any lose if we have many rows in a CF say 10 million?

Thanks,
Dushyant


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herein are not intended to be, and do not constitute, advice within the meaning of Section
975 of the Dodd-Frank Wall Street Reform and Consumer Protection Act. If you have received
this communication in error, please destroy all electronic and paper copies and notify the
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