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https://issues.apache.org/jira/browse/HIVE-18079?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16472919#comment-16472919
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Gopal V commented on HIVE-18079:
--------------------------------
Rebased patches and there are some row-order flakiness
tez_vector_dynpart_hashjoin_1.q.out
{code}
--13036 1
+-8915 1
-3799 1
10782 1
--8915 1
+-13036 1
{code}
where the order by is on the column having "1".
unionDistinct_1.q has a -- SORT_BEFORE_DIFF in it, so the result change won't
break runs.
> Statistics: Allow HyperLogLog to be merged to the lowest-common-denominator
> bit-size
> ------------------------------------------------------------------------------------
>
> Key: HIVE-18079
> URL: https://issues.apache.org/jira/browse/HIVE-18079
> Project: Hive
> Issue Type: Improvement
> Components: Standalone Metastore, Statistics
> Affects Versions: 3.0.0
> Reporter: Gopal V
> Assignee: Gopal V
> Priority: Major
> Attachments: HIVE-18079.1.patch, HIVE-18079.10.patch,
> HIVE-18079.11.patch, HIVE-18079.2.patch, HIVE-18079.4.patch,
> HIVE-18079.5.patch, HIVE-18079.6.patch, HIVE-18079.7.patch,
> HIVE-18079.8.patch, HIVE-18079.9.patch
>
>
> HyperLogLog can merge a 14 bit HLL into a 10 bit HLL bitset, because of its
> mathematical hash distribution & construction.
> Allow the squashing of a 14 bit HLL -> 10 bit HLL without needing a second
> scan over the data-set.
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