Question pertaining to wide or large rows in Cassandra. I recall reading in a blog I believe posted by Aaron Morton a notation that Cassandra creates its own index of a row when it reaches X amount of columns? My curiosity is:

A.) At what column count does this happen?
B.) If Thrift is only getting slices of a large row (column_start=X, column_end=Y, limit 20) is their any performance hits to rows over and above the A.) threshold above?

Finally, I am correct in thinking the cluster may appear slightly unbalanced depending on the RF and the amount of nodes with a great deal of large rows?

note: using php_cassa & Cassandra 0.8.10

Thanks!