On Apr 23, 2016, at 3:10 PM, Jay Pipes <jaypi...@gmail.com
<mailto:jaypi...@gmail.com>> wrote:
> BTW, note to Ed Leafe... unless your distributed data store supports
> transactional semantics, you can't use a distributed data store for these
> types of solutions. Instead, you will need to write a whole bunch of code
> that does post-auditing of claims and quotas and a system that accepts that
> oversubscription and out-of-sync quota limits and usages is a fact of life.
Yes, that was one of the things that I liked about Cassandra:
http://www.datastax.com/dev/blog/lightweight-transactions-in-cassandra-2-0
<http://www.datastax.com/dev/blog/lightweight-transactions-in-cassandra-2-0>
For instance, in the scheduler, making a claim would simply fail if another
process had changed any of the resources in question, as the transaction would
not be allowed.
> Not to mention needing to implement JOINs in Python.
Heh, JOIN in a column family database is not needed. You do have to think about
data a lot differently, and that means unlearning everything you know about
normalization. As a long-time SQL DB admin, it took my brain quite some time to
be able to understand the different approach.
-- Ed Leafe
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