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From Jonathan Ellis <>
Subject Re: Would it be possible to do a ColumnCache?
Date Thu, 21 Oct 2010 05:02:19 GMT
I don't think it's possible.  Cassandra's data model means you can't
know what columns are present in a row, so if you query, say, name and
birthdate from your users column family and only the name column is in
the cache for the row you are querying, does that mean that birthdate
doesn't exist in that row?  Or just that it's not cached?  You don't
know, so you'd have to do a full read every time.  Similar
difficulties arise with slices.

2010/10/20 H├ęctor Izquierdo Seliva <>:
> Hi. Before wasting time in something that might not be feasible at the
> moment, I wanted to ask the devs if a column cache would be possible
> (instead of a whole row cache). This would allow users with fat rows to
> also use a cache and reduce latency for hot data.
> If this is possible, i'd appreciate some hints about where to dig.
> Thanks for your time!

Jonathan Ellis
Project Chair, Apache Cassandra
co-founder of Riptano, the source for professional Cassandra support

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