On Mon, Oct 11, 2010 at 04:01, Arijit Mukherjee <ariji...@gmail.com> wrote: > Hi All > > I've just started reading about Cassandra and writing simple tests > using Cassandra 0.6.5 to see if we can use it for our product. > > I have a data store with a set of columns, like C1, C2, C3, and C4, > but the columns aren't mandatory. For example, there can be a list of > (k.v) pairs with only C1 and C2, but no C3 and C4. At the same time, > there can be a set of records with all the columns present. It's > possible to consider them as three sets A (with all columns), B (with > C1 and C2) and C (with C3 and C4). And I'm trying to find out the > following: > > 1. A - B (all records who don't have C3 and C4) and A - C (all record > who don't have C1 and C2) > 2. records for whom C2 != C4 > > It's possible to pick all records and do this processing in my client > code - but that won't perform well. Is there any way to do these > within Cassandra? For example, by passing a list of column names so > that cassandra returns the records with only those columns?
multiget_slice with the SlicePredicate specified using column_names can do the lookups. As far as doing the set operations: no, Cassandra doesn't have the ability to do this server-side. Gary. > > Regards > Arijit >
