Thanks Adam, that's good to know. On Wed, Mar 9, 2016 at 7:42 AM, Adam Holmberg <adam.holmb...@datastax.com> wrote:
> The referenced article is accurate as far as NULL is concerned, but please > also note that there is now the ability to specify UNSET to avoid > unnecessary tombstones (as of Cassandra 2.2.0): > https://issues.apache.org/jira/browse/CASSANDRA-7304 > > Adam > > On Tue, Mar 8, 2016 at 12:15 PM, Henry M <henrymanm...@gmail.com> wrote: > >> Thank you. It's probably not specific to prepared statements then and >> just a more general statement. That makes sense. >> >> >> On Tue, Mar 8, 2016 at 10:06 AM Steve Robenalt <sroben...@highwire.org> >> wrote: >> >>> 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 >>> >> > -- 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
