Alessandro Solimando

Resolved conflicts with current master

The changes LGTM, however, I find a bit weird that `IS TRUE` is mentioned all over the code but not featuring at all in the unit tests. Can you expand...

Please keep the PR open

@yulongz I am confused here, in [current master](https://github.com/apache/hive/blob/bc35507757c23a6da612a2dc4b840105aed2515c/ql/src/java/org/apache/hadoop/hive/ql/exec/PTFOperator.java#L83) I can already see `currentKeys` set to `null` in the very same place you proposed the change. Am I missing something? The...

Before going into the single discussions, the general answer to all the above comments boils down to "I am trying to keep consistency with what was done here for vectorizing...

> PR-1824 has nothing to do with datasketches; I don't know how you followed it's conventions but you might end up in trouble...because DS also has a HLL implementation...wouldn't that...

Please keep the PR open

Please keep it open

Rebased on master in order to take advantage of PR-[3637](https://github.com/apache/hive/pull/3637) to support KLL sketch size parameter in the constructor (otherwise we will miss vectorization opportunities when the UDAF is used...

Rebasing on master