Tim Armstrong has posted comments on this change.

Change subject: IMPALA-1430: enable codegen for native UDAs
......................................................................


Patch Set 10:

(7 comments)

http://gerrit.cloudera.org:8080/#/c/5161/10/be/src/exprs/agg-fn-evaluator.cc
File be/src/exprs/agg-fn-evaluator.cc:

PS10, Line 539:     // The last (in/out) argument is exposed to UDAs via the 
FunctionContext as the
              :     // return type, rather than as the last argument type. 
Constant inlining must
              :     // therefore expose it in the same way.
> May help to add a remark in aggregate-functions-ir.cc about the assumption 
I realised that FunctionContext is probably the right place to document this 
(since it's really the contract of GetReturnType() and friends). So I briefly 
augmented some of the comments there to mention UDA args.

When reading those comments I realised that there was a bug here - 
GetReturnType() is documented to return the return type of Finalize() rather 
than the intermediate type. I fixed that here and filed IMPALA-4785 to add 
constant propagation for intermediate_type().


http://gerrit.cloudera.org:8080/#/c/5161/10/be/src/exprs/scalar-fn-call.h
File be/src/exprs/scalar-fn-call.h:

PS10, Line 53: or HDFS
> or external module ?
library?


PS10, Line 54:  UDF
> It could also be the update/merge function of a UDA, right ? Not sure if it
I reworded just to refer to it as a function.

I could also move this to a different class - I didn't want to start off doing 
that since it would make the diff harder to review.


PS10, Line 61:  
> nit: extra blank space.
Done


http://gerrit.cloudera.org:8080/#/c/5161/10/be/src/udf/udf-internal.h
File be/src/udf/udf-internal.h:

PS10, Line 51: UDAF
> May be less confusing to say "UDA functions"
UDAs seems more consistent.


PS10, Line 52: an Expr node
             : /// generated by the Impala frontend
> May be it helps to differentiate the ExprNode in the FE and BE b stating:
Done


PS10, Line 54:  Backend code should not create FunctionContexts for other
             : /// purposes
> FunctionContexts should entirely be allocated and managed by ExprContext. E
Done


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Gerrit-MessageType: comment
Gerrit-Change-Id: Id1708eaa96eb76fb9bec5eeabf209f81c88eec2f
Gerrit-PatchSet: 10
Gerrit-Project: Impala-ASF
Gerrit-Branch: master
Gerrit-Owner: Tim Armstrong <[email protected]>
Gerrit-Reviewer: Marcel Kornacker <[email protected]>
Gerrit-Reviewer: Michael Ho
Gerrit-Reviewer: Michael Ho <[email protected]>
Gerrit-Reviewer: Tim Armstrong <[email protected]>
Gerrit-HasComments: Yes

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