You could try this. C* doesn't do it all for you, but it will efficiently get you the right data.
-ml -- put this in <file> and run using 'cqlsh -f <file> DROP KEYSPACE latest; CREATE KEYSPACE latest WITH replication = { 'class': 'SimpleStrategy', 'replication_factor' : 1 }; USE latest; CREATE TABLE time_series ( userid text, pkid text, colname map<text, text>, PRIMARY KEY (userid, pkid) ); UPDATE time_series SET colname = colname + {'200':'Col-Name-1'} WHERE userid = 'XYZ' AND pkid = '1000'; UPDATE time_series SET colname = colname + {'201':'Col-Name-2'} WHERE userid = 'XYZ' AND pkid = '1001'; UPDATE time_series SET colname = colname + {'202':'Col-Name-3'} WHERE userid = 'XYZ' AND pkid = '1000'; UPDATE time_series SET colname = colname + {'203':'Col-Name-4'} WHERE userid = 'XYZ' AND pkid = '1000'; UPDATE time_series SET colname = colname + {'204':'Col-Name-5'} WHERE userid = 'XYZ' AND pkid = '1002'; SELECT * FROM time_series WHERE userid = 'XYZ'; -- returns: -- userid | pkid | colname ----------+------+----------------------------------------------------------------- -- XYZ | 1000 | {'200': 'Col-Name-1', '202': 'Col-Name-3', '203': 'Col-Name-4'} -- XYZ | 1001 | {'201': 'Col-Name-2'} -- XYZ | 1002 | {'204': 'Col-Name-5'} -- use an app to pop off the latest key/value from the map for each row, then sort by key desc. On Tue, Sep 10, 2013 at 9:21 AM, Ravikumar Govindarajan < ravikumar.govindara...@gmail.com> wrote: > I have been faced with a problem of grouping composites on the second-part. > > Lets say my CF contains this > > > TimeSeriesCF > key: UserID > composite-col-name: TimeUUID:PKID > > Some sample data > > UserID = XYZ > Time:PKID > Col-Name1 = 200:1000 > Col-Name2 = 201:1001 > Col-Name3 = 202:1000 > Col-Name4 = 203:1000 > Col-Name5 = 204:1002 > > Whenever a time-series query is issued, it should return the following in > time-desc order. > > UserID = XYZ > Col-Name5 = 204:1002 > Col-Name4 = 203:1000 > Col-Name2 = 201:1001 > > Is something like this possible in Cassandra? Is there a different way to > design and achieve the same objective? > > -- > Ravi > >