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https://issues.apache.org/jira/browse/HIVE-1841?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12983405#action_12983405
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Carl Steinbach commented on HIVE-1841:
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Note that having datanucleus.autoCreateSchema=true and
datanucleus.fixedDatastore=false also results
in a significant performance hit for MetaStore operations.
See http://www.jpox.org/servlet/forum/viewthread_thread,4066
> datanucleus.fixedDatastore should be true in hive-default.xml
> --------------------------------------------------------------
>
> Key: HIVE-1841
> URL: https://issues.apache.org/jira/browse/HIVE-1841
> Project: Hive
> Issue Type: Improvement
> Components: Configuration
> Affects Versions: 0.6.0
> Reporter: Edward Capriolo
> Fix For: 0.7.0
>
> Attachments: HIVE-1841.1.patch.txt
>
>
> Two datanucleus variables:
> {noformat}
> <property>
> <name>datanucleus.autoCreateSchema</name>
> <value>false</value>
> </property>
> <property>
> <name>datanucleus.fixedDatastore</name>
> <value>true</value>
> </property>
> {noformat}
> are dangerous. We do want the schema to auto-create itself, but we do not
> want the schema to auto update itself.
> Someone might accidentally point a trunk at the wrong meta-store and
> unknowingly update. I believe we should set this to false and possibly trap
> exceptions stemming from hive wanting to do any update. This way someone has
> to actively acknowledge the update, by setting this to true and then starting
> up hive, or leaving it false, removing schema modifies for the user that hive
> usages, and doing all the time and doing the updates by hand.
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