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https://issues.apache.org/jira/browse/HIVE-22239?focusedWorklogId=324943&page=com.atlassian.jira.plugin.system.issuetabpanels:worklog-tabpanel#worklog-324943
]
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_r332357556
##########
File path: ql/src/java/org/apache/hadoop/hive/ql/stats/StatsUtils.java
##########
@@ -856,8 +856,15 @@ public static ColStatistics
getColStatistics(ColumnStatisticsObj cso, String tab
} else if (colTypeLowerCase.equals(serdeConstants.BINARY_TYPE_NAME)) {
cs.setAvgColLen(csd.getBinaryStats().getAvgColLen());
cs.setNumNulls(csd.getBinaryStats().getNumNulls());
- } else if (colTypeLowerCase.equals(serdeConstants.TIMESTAMP_TYPE_NAME) ||
- colTypeLowerCase.equals(serdeConstants.TIMESTAMPLOCALTZ_TYPE_NAME)) {
+ } else if (colTypeLowerCase.equals(serdeConstants.TIMESTAMP_TYPE_NAME)) {
+ cs.setAvgColLen(JavaDataModel.get().lengthOfTimestamp());
+ cs.setNumNulls(csd.getTimestampStats().getNumNulls());
+ Long lowVal = (csd.getTimestampStats().getLowValue() != null) ?
csd.getTimestampStats().getLowValue()
+ .getSecondsSinceEpoch() : null;
+ Long highVal = (csd.getTimestampStats().getHighValue() != null) ?
csd.getTimestampStats().getHighValue()
+ .getSecondsSinceEpoch() : null;
+ cs.setRange(lowVal, highVal);
Review comment:
I don't feel this fortunate....we do know the low/high value but we faltten
it to some number...instead of this we would need properly typed ranges - for
decimal we already throw away all our knowledge if it runs beyond long limits
the current changes follow the existing traditions - if we decide to change
that ; it should be done in a separate ticket
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Issue Time Tracking
-------------------
Worklog Id: (was: 324943)
Time Spent: 1h (was: 50m)
> 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
> 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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