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https://issues.apache.org/jira/browse/HIVE-600?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12742185#action_12742185
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Yuntao Jia commented on HIVE-600:
---------------------------------
To the 1st question, the reduce number is set in Hive. In particular, in
Hive-default.xml, one property is:
<property>
<name>mapred.reduce.tasks</name>
<value>-1</value>
<description>The default number of reduce tasks per job. Typically set
to a prime close to the number of available hosts. Ignored when
mapred.job.tracker is "local". Hadoop set this to 1 by default, whereas hive
uses -1 as its default value.
By setting this property to -1, Hive will automatically figure out what
should be the number of reducers.
</description>
</property>
To the 2nd question, in the actual Hadoop configuration, we did use four paths.
However, for security reasons, we anonymized the configuration file and put one
path instead.
Hope that answers your questions.
> Running TPC-H queries on Hive
> -----------------------------
>
> Key: HIVE-600
> URL: https://issues.apache.org/jira/browse/HIVE-600
> Project: Hadoop Hive
> Issue Type: New Feature
> Reporter: Yuntao Jia
> Assignee: Yuntao Jia
> Attachments: TPC-H_on_Hive_2009-08-11.pdf,
> TPC-H_on_Hive_2009-08-11.tar.gz
>
>
> The goal is to run all TPC-H (http://www.tpc.org/tpch/) benchmark queries on
> Hive for two reasons. First, through those queries, we would like to find the
> new features that we need to put into Hive so that Hive supports common SQL
> queries. Second, we would like to measure the performance of Hive to find out
> what Hive is not good at. We can then improve Hive based on those
> information.
> For queries that are not supported now in Hive, I will try to rewrite them to
> one or more Hive-supported queries.
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