Thank you Aaron!! But, If you are reading partial rows(that otherwise contain several thousands of **valueless** columns) then do the column indexes help in making the reads faster & more efficient than if they were not valueless? Perhaps, because they would only need to look up whether the asked column names exist in indexes for that row/key & they dont need to deserialize the blocks in SST tables searching for column values. Am I thinking right way??
-Aditya On Fri, Feb 11, 2011 at 1:54 AM, Aaron Morton <aa...@thelastpickle.com> wrote: > If you want to get the byte size of a particular row you will need to read it > all back. > > If you connect with JConsole at look at you column families, there are > attributes for the max, min and mean row sizes. > > In general the entire row only exists in memory when it is contained in the > first Memtable it's written to. It may then be partially or fully read from > disk during subsequent reads or compactions. > > On disk format described here may help > http://wiki.apache.org/cassandra/ArchitectureSSTable > > Hope that helps > Aaron > On 10/02/2011, at 11:56 PM, Aditya Narayan <ady...@gmail.com> wrote: > >> How can I get or calculate the size of rows/ columns ? what are the >> any overheads on memory for each column/row ? >
