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https://issues.apache.org/jira/browse/HIVE-22538?focusedWorklogId=377700&page=com.atlassian.jira.plugin.system.issuetabpanels:worklog-tabpanel#worklog-377700
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ASF GitHub Bot logged work on HIVE-22538:
-----------------------------------------
Author: ASF GitHub Bot
Created on: 27/Jan/20 15:29
Start Date: 27/Jan/20 15:29
Worklog Time Spent: 10m
Work Description: kasakrisz commented on pull request #877: HIVE-22538:
RS deduplication does not always enforce
hive.optimize.reducededuplication.min.reducer
URL: https://github.com/apache/hive/pull/877#discussion_r371307699
##########
File path: ql/src/test/results/clientpositive/autoColumnStats_4.q.out
##########
@@ -128,16 +127,20 @@ STAGE PLANS:
Statistics: Num rows: 10 Data size: 1728 Basic stats: COMPLETE
Column stats: COMPLETE
Group By Operator
aggregations: compute_stats(a, 'hll'), compute_stats(b, 'hll')
- minReductionHashAggr: 0.99
- mode: hash
+ mode: complete
Review comment:
Enabling parallelism when inserting eliminates this change.
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Issue Time Tracking
-------------------
Worklog Id: (was: 377700)
Time Spent: 1h 10m (was: 1h)
> RS deduplication does not always enforce
> hive.optimize.reducededuplication.min.reducer
> --------------------------------------------------------------------------------------
>
> Key: HIVE-22538
> URL: https://issues.apache.org/jira/browse/HIVE-22538
> Project: Hive
> Issue Type: Bug
> Components: Physical Optimizer
> Reporter: Jesus Camacho Rodriguez
> Assignee: Krisztian Kasa
> Priority: Major
> Labels: pull-request-available
> Attachments: HIVE-22538.2.patch, HIVE-22538.3.patch,
> HIVE-22538.4.patch, HIVE-22538.5.patch, HIVE-22538.6.patch,
> HIVE-22538.6.patch, HIVE-22538.7.patch, HIVE-22538.8.patch, HIVE-22538.patch
>
> Time Spent: 1h 10m
> Remaining Estimate: 0h
>
> For transactional tables, that property might be overriden to 1, which can
> lead to merging final aggregation into a single stage (hence leading to
> performance degradation). For instance, when autogather column stats is
> enabled, this can happen for the following query:
> {code}
> set hive.support.concurrency=true;
> set hive.txn.manager=org.apache.hadoop.hive.ql.lockmgr.DbTxnManager;
> EXPLAIN
> CREATE TABLE x STORED AS ORC TBLPROPERTIES('transactional'='true') AS
> SELECT * FROM SRC x CLUSTER BY x.key;
> {code}
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