Dan Hecht has posted comments on this change.

Change subject: IMPALA-5788: Fix agg node crash when grouping by 
nondeterministic exprs
......................................................................


Patch Set 3:

(4 comments)

http://gerrit.cloudera.org:8080/#/c/7714/3/be/src/exec/partitioned-aggregation-node.cc
File be/src/exec/partitioned-aggregation-node.cc:

Line 1156: 
nit: to get more code on the screen, i think we can do without blank lines 
where the code is so closely related.


Line 1160:   // partition index.
in the case where we do repartition (and prior to IMPALA-2708), what happens? 
the row gets shuffled around random partitions in each iteration? do things 
actually work in any meaningful way?

I see how doing this avoids the crash, but have we thought about just giving an 
error when the grouping expression is non-deterministic? do we think that 
breaks important queries and that they had worked in meaningful ways?


http://gerrit.cloudera.org:8080/#/c/7714/3/be/src/exec/partitioned-aggregation-node.h
File be/src/exec/partitioned-aggregation-node.h:

PS3, Line 338: all pointers in this vector will point to a single
             :   /// in-memory partition
outside of the context of this bug fix, it's hard to see why things would be 
set up that way. Is there some logical way we can justify it?


Line 344:   /// hash table part of a single in-memory partition
same


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Gerrit-MessageType: comment
Gerrit-Change-Id: Ibdb09239577b3f0a19d710b0d148e882b0b73e23
Gerrit-PatchSet: 3
Gerrit-Project: Impala-ASF
Gerrit-Branch: master
Gerrit-Owner: Bikramjeet Vig <[email protected]>
Gerrit-Reviewer: Bikramjeet Vig <[email protected]>
Gerrit-Reviewer: Dan Hecht <[email protected]>
Gerrit-Reviewer: Tim Armstrong <[email protected]>
Gerrit-HasComments: Yes

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