Hi Henry, I would suspect that the tombstones are necessary to overwrite any previous values in the null'd columns. Since Cassandra avoids read-before-write, there's no way to be sure that the nulls were not intended to remove any such previous values, so the tombstones insure that they don't re-appear.
Steve On Tue, Mar 8, 2016 at 9:36 AM, Henry Manasseh <henrymanm...@gmail.com> wrote: > The following article makes the following statement which I am trying to > understand: > > *"Cassandra’s storage engine is optimized to avoid storing unnecessary > empty columns, but when using prepared statements those parameters that are > not provided result in null values being passed to Cassandra (and thus > tombstones being stored)." * > http://www.datastax.com/dev/blog/4-simple-rules-when-using-the-datastax-drivers-for-cassandra > > I was wondering if someone could help explain why sending nulls as part of > a prepared statement update would result in tombstones. > > Thank you, > - Henry > -- Steve Robenalt Software Architect sroben...@highwire.org <bza...@highwire.org> (office/cell): 916-505-1785 HighWire Press, Inc. 425 Broadway St, Redwood City, CA 94063 www.highwire.org Technology for Scholarly Communication
