Hello, In a Cassandra cluster I want to push a notification to rabbitmq whenever a change (insert/update/delete) was made to some Cassandra tables, with the following requirements: The notifications should:
1. Be ordered in the same order the changes were stored. 2. Be sent only if the change was (or going to be) committed successfully. And in case of insert/update: 3. Include all the row values. 4. Indicate what values were changed. I'm trying to figure out if Cassandra triggers are the correct way to go. According to http://www.datastax.com/dev/blog/whats-new-in-cassandra-2-0-prototype-triggers-support, one of the potential use cases for triggers is: * >> implementing alerts/notifications I also played a bit with the example given here: http://stackoverflow.com/questions/35161747/example-of-creating-triggers-in-cassandra-and-does-this-support-only-for-java and from what I read and learned so far I assume that: Regarding #1, I doubt if the notification order can be kept since the trigger is invoked on the coordinator node while there are multiple clients that can connect to the various cluster nodes (coordinators). Regarding #2, I'm not sure that notification will be sent only for changes that are going to be committed successfully since the trigger is invoked before the change is being applied. Regarding #3, I seen that this requirement is fulfilled. Regarding #4, I didn't find a way to figure out what values are actually changed, without re-reading the current (old) values from the table which of course impose a significant performance penalty. Are my assumptions correct? If yes then triggers are not the right approach. What other ways can be taken? Regards, Oren
