Tim Armstrong has posted comments on this change.

Change subject: IMPALA-1286: Extract common conjuncts from disjunctions.
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Patch Set 5:

I understand that it's harmless in that queries that succeeded before the patch 
won't start failing after the patch, but I'm concerned that a) queries that 
succeed with optimisation on will fail or behave differently when you turn 
optimisations off because the analyser picks a wider type and b) the lack of 
distinction between user-visible types and "internal" types will be a source of 
bugs and confusing behaviour.

There may only be a couple of cases where this is user-visible (CTAS and 
typeof() come to mind), so maybe there's a way to fix that there.

The longer-term design concern is if there aren't clear rules for determining 
the types of expressions that can be applied during the initial semantic 
analysis (e.g. BOOL || BOOL => BOOL), it makes it very hard to change the 
implementation of the frontend without changing the user-visible behaviour of 
the frontend.

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Gerrit-MessageType: comment
Gerrit-Change-Id: I3cf9b950afaa3fd753d1b09ba5e540b5258940ad
Gerrit-PatchSet: 5
Gerrit-Project: Impala-ASF
Gerrit-Branch: master
Gerrit-Owner: Alex Behm <[email protected]>
Gerrit-Reviewer: Alex Behm <[email protected]>
Gerrit-Reviewer: Bharath Vissapragada <[email protected]>
Gerrit-Reviewer: Marcel Kornacker <[email protected]>
Gerrit-Reviewer: Tim Armstrong <[email protected]>
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