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Posted to issues@hive.apache.org by "Peter Vary (Jira)" <ji...@apache.org> on 2020/01/06 09:05:00 UTC
[jira] [Commented] (HIVE-22538) RS deduplication does not always
enforce hive.optimize.reducededuplication.min.reducer
[ https://issues.apache.org/jira/browse/HIVE-22538?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17008647#comment-17008647 ]
Peter Vary commented on HIVE-22538:
-----------------------------------
[~kgyrtkirk] suggested to take a look at PlanUtils.getReduceSinkDesc - just taking a note, so I can get back when I have time.
> 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: Jesus Camacho Rodriguez
> Priority: Major
> Labels: pull-request-available
> Attachments: HIVE-22538.patch
>
> Time Spent: 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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