On May 3, 2016, at 6:45 AM, Miles Gould <mgo...@redhat.com> wrote: >> This DB could be an RDBMS or Cassandra, depending on the deployer's >> preferences > AFAICT this would mean introducing and maintaining a layer that abstracts > over RDBMSes and Cassandra. That's a big abstraction, over two quite > different systems, and it would be hard to write code that performs well in > both cases. If performance in this layer is critical, then pick whichever DB > architecture handles the expected query load better and use that.
Agreed - you simply can’t structure the data the same way. When I read criticisms of Cassandra that include “you can’t do joins” or “you can’t aggregate”, it highlights this fact: you have to think about (and store) your data completely differently than you would in an RDBMS. You cannot simply abstract out the differences. -- Ed Leafe __________________________________________________________________________ OpenStack Development Mailing List (not for usage questions) Unsubscribe: openstack-dev-requ...@lists.openstack.org?subject:unsubscribe http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-dev
