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https://issues.apache.org/jira/browse/HIVE-1841?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12969413#action_12969413
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Ning Zhang commented on HIVE-1841:
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The hive-default.xml only set the first to true. This is good for first-time
users to quickly get things started (by automatically creating tables needed by
metastore) without changing any configurations. This removes frictions for the
beginners.
For experts or administrators for production clusters, these parameters can be
set in hive-site.xml. This is actually what we are doing at Facebook (setting
fixed metastore schema). I think this will give you both the
flexibility/configurability as well as security. What do you think?
> 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
>
>
> 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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