Thx for the answer 1 more thing, a Composite key is not hashed only once I guess? It's hashed the number of part the composite have? So this means there are twice or 3 or ... as many keys as for normal column keys, is it true? Le 31 mai 2012 02:59, "aaron morton" <aa...@thelastpickle.com> a écrit :
> Composite Columns compare each part in turn, so the values are ordered as > you've shown them. > > However the rows are not ordered according to key value. They are ordered > using the random token generated by the partitioner see > http://wiki.apache.org/cassandra/FAQ#range_rp > > What is the real advantage compared to super column families? > > They are faster. > > Cheers > > ----------------- > Aaron Morton > Freelance Developer > @aaronmorton > http://www.thelastpickle.com > > On 29/05/2012, at 10:08 PM, Cyril Auburtin wrote: > > How is it done in Cassandra to be able to range query on a composite key? > > "key1" => (A:A:C), (A:B:C), (A:C:C), (A:D:C), (B,A,C) > > like get_range ("key1", start_column=(A,"), end_column=(A, C)); will > return [ (A:B:C), (A:C:C) ] (in pycassa) > > I mean does the composite implementation add much overhead to make it work? > Does it need to add other Column families, to be able to range query > between composites simple keys (first, second and third part of the > composite)? > > What is the real advantage compared to super column families? > > "key1" => A: (A,C), (B,C), (C,C), (D,C) , B: (A,C) > > thx > > >
