Re Anthony's statement: > So it can be done and frameworks like CAGES are showing a way forward. At > the heart of it, there will need to be a Two-Phase commit type protocol > coordinator that sits in front of Cassandra. Of which - one can be sure - there > will be many implementations / best practices in the coming months.
I disagree. I think anyone who wants transactions should pick a database that supports them. Bolting a transactional system on top could perhaps be made to work at great cost if you always used CL ALL for every operation. I personally don't think it's possible, but I can't actually prove it. Consider how to enforce: 1) atomicity: you need some kind of undo/redo logging system with crash recovery to handle partially-executed transactions. This is a lot of tricky Cassandra-specific code. A locking system isn't good enough. 2) isolation: lock managers are f*&^ing hard, especially handling the failure cases. Performant deadlock detection is difficult. Getting sufficiently fine-grained locks would require Cassandra-specific code. I'm trying to argue that these features belong inside the database, and not bolted on top, so you should use a database that includes them. Plainly: don't use Cassandra for applications that require transactions. However, if you can express your app without the need of transactions, that where Cassandra really shines. +1 on Nate's recommendation to read the Helland paper. Contentiously, Dave On Wed, Feb 16, 2011 at 2:20 PM, Nate McCall <n...@datastax.com> wrote: > I found the following paper (PDF) very helpful in shaping my thoughts > about what it means to build systems without transactions. > > http://www.ics.uci.edu/~cs223/papers/cidr07p15.pdf > > "LIfe Beyond Distributed Transactions: an Apostate's Opinion" by Pat > Helland > > On Wed, Feb 16, 2011 at 2:00 PM, tijoriwala.ritesh > <tijoriwala.rit...@gmail.com> wrote: > > > > Thanks a lot Anthony. That does help me think on possible options... > > -- > > View this message in context: > http://cassandra-user-incubator-apache-org.3065146.n2.nabble.com/Patterns-for-writing-enterprise-applications-on-cassandra-tp6030077p6033316.html > > Sent from the cassandra-u...@incubator.apache.org mailing list archive > at Nabble.com. > > >
