On Sun, May 12, 2013 at 6:26 PM, Edward Capriolo <edlinuxg...@gmail.com> wrote: > 2 billion is the maximum theoretically limit of columns under a row. It is > NOT the maximum limit of a CQL collection. The design of CQL collections > currently require retrieving the entire collection on read.
Each column has a byte overhead of 15 bytes [1]. Assuming a column key of type "int" [2] and no column value, a 2 billion column row is approximately 35 gigabytes. This is before including the column index. Anyone attempting to actually create and interact with a single row containing 2 billion columns seems likely to quickly discover just how meaningless the theoretical maximum is, so I'm not sure why we refer to this number.. =Rob [1] http://btoddb-cass-storage.blogspot.com/2011/07/column-overhead-and-sizing-every-column.html [2] The minimum size to actually have 2Bn unique column keys.
