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https://issues.apache.org/jira/browse/CALCITE-1436?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16497927#comment-16497927
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Muhammad Gelbana commented on CALCITE-1436:
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Would someone please shed some light on what needs to be done here ? I believe
[~vladimirsitnikov]\[~vlsi] is the author of [this
change|[https://github.com/apache/calcite/commit/ddad58826121d29362539f240ea32660811dc09b#diff-964b02bd21a99d18828586e07bb88aa7].]
Would you please provide more information ?
I can think of two ways to fix this. I either create an accumulator following
the same interface as IntSum, LongSum and DoubleSum and
{code:java}
return new UdaAccumulatorFactory(AggregateFunctionImpl.create(IntMin.class),
call, true); // That's for Integral input{code}
Just as what the SUM branch does.
Or,
Considering that I'm trying to support MIN and MAX aggregate functions, I'll
have to initialize the *state* list with only one element that represents the
calculated minimum\maximum value. Should this expression be of type
ParameterExpression ? This will have to be done in the AggImpState constructor
of course. But this is still complicated to me, I appreciate some
clarifications please.
> AggregateNode NPE for aggregators other than SUM/COUNT
> ------------------------------------------------------
>
> Key: CALCITE-1436
> URL: https://issues.apache.org/jira/browse/CALCITE-1436
> Project: Calcite
> Issue Type: Bug
> Components: core
> Reporter: Gian Merlino
> Assignee: Julian Hyde
> Priority: Major
>
> AggregateNode.getAccumulator does this for any aggregation other than COUNT
> or SUM:
> final AggImpState agg = new AggImpState(0, call, false);
> int stateSize = agg.state.size();
> This NPEs because "state" is null on freshly created AggImpState instances.
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