Github user kunal642 commented on the issue:
https://github.com/apache/carbondata/pull/1476
@jackylk We have an Event architecture which can be used to perform pre and
post actions. I think it is better to add the validations in pre listeners.
Another point is that if we add validation in a strategy like in #1447 then
we would have to look up the carbon table twice(once for validation and other
in the actual flow) which would decrease the performance. In listener
interface, we can be shared the carbon table among various listeners.
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