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https://issues.apache.org/jira/browse/HIVE-22239?focusedWorklogId=324950&page=com.atlassian.jira.plugin.system.issuetabpanels:worklog-tabpanel#worklog-324950
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ASF GitHub Bot logged work on HIVE-22239:
-----------------------------------------
Author: ASF GitHub Bot
Created on: 08/Oct/19 08:47
Start Date: 08/Oct/19 08:47
Worklog Time Spent: 10m
Work Description: kgyrtkirk commented on pull request #787: HIVE-22239
URL: https://github.com/apache/hive/pull/787#discussion_r332383859
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File path: ql/src/test/results/clientpositive/llap/subquery_select.q.out
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@@ -3918,14 +3918,14 @@ STAGE PLANS:
Statistics: Num rows: 26 Data size: 208 Basic stats:
COMPLETE Column stats: COMPLETE
Filter Operator
predicate: p_partkey BETWEEN 10000 AND 20000 (type:
boolean)
- Statistics: Num rows: 8 Data size: 64 Basic stats:
COMPLETE Column stats: COMPLETE
+ Statistics: Num rows: 1 Data size: 8 Basic stats: COMPLETE
Column stats: COMPLETE
Select Operator
expressions: p_size (type: int)
outputColumnNames: p_size
- Statistics: Num rows: 8 Data size: 64 Basic stats:
COMPLETE Column stats: COMPLETE
+ Statistics: Num rows: 1 Data size: 8 Basic stats:
COMPLETE Column stats: COMPLETE
Group By Operator
aggregations: max(p_size)
- minReductionHashAggr: 0.875
+ minReductionHashAggr: 0.0
Review comment:
the computed range is most likely empty...
these changes suggest to me that something is not entirely right....is this
expected?
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Issue Time Tracking
-------------------
Worklog Id: (was: 324950)
Time Spent: 1h 40m (was: 1.5h)
> Scale data size using column value ranges
> -----------------------------------------
>
> Key: HIVE-22239
> URL: https://issues.apache.org/jira/browse/HIVE-22239
> Project: Hive
> Issue Type: Improvement
> Components: Physical Optimizer
> Reporter: Jesus Camacho Rodriguez
> Assignee: Jesus Camacho Rodriguez
> Priority: Major
> Labels: pull-request-available
> Attachments: HIVE-22239.01.patch, HIVE-22239.02.patch,
> HIVE-22239.patch
>
> Time Spent: 1h 40m
> Remaining Estimate: 0h
>
> Currently, min/max values for columns are only used to determine whether a
> certain range filter falls out of range and thus filters all rows or none at
> all. If it does not, we just use a heuristic that the condition will filter
> 1/3 of the input rows. Instead of using that heuristic, we can use another
> one that assumes that data will be uniformly distributed across that range,
> and calculate the selectivity for the condition accordingly.
> This patch also includes the propagation of min/max column values from
> statistics to the optimizer for timestamp type.
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