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Lars Hofhansl commented on PHOENIX-2965:
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Thanks [~giacomotaylor].
# DistinctCountAggregateFunction is only used in the first case. The 2nd case
already works correctly.
# The check for {{!isUngroupedAggregate}} is needed to that the statement is
not flagged as incorrect. Before my change it bailed out earlier (returning
{{UNGROUPED_GROUP_BY}}), to use the optimization we need to check whether the
DISTINCT part is order preserving or not.
# I'll check out the queries you mentioned. These are all interesting.
# Interestingly a COUNT(DISTINCT) will _not_ mark the statement as distinct.
Could fix that, but I thought is safer to check explicitly. I do think all
these checks are needed. I'll check the cases you mention.
Stand by :)
> Use DistinctPrefixFilter logic for COUNT(DISTINCT ...) and COUNT(...) GROUP BY
> ------------------------------------------------------------------------------
>
> Key: PHOENIX-2965
> URL: https://issues.apache.org/jira/browse/PHOENIX-2965
> Project: Phoenix
> Issue Type: Sub-task
> Reporter: Lars Hofhansl
> Fix For: 4.8.0
>
> Attachments: 2965-v2.txt, 2965-v3.txt, 2965.txt
>
>
> Parent uses skip scanning to optimize DISTINCT and certain GROUP BY
> operations along the row key.
> COUNT queries are optimized differently, could be sped up significantly as
> well.
> [~giacomotaylor], I might need to help into where COUNT(DISTINCT) queries are
> planned and optimized.
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