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https://issues.apache.org/jira/browse/HIVE-1841?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15005800#comment-15005800
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Lefty Leverenz commented on HIVE-1841:
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Doc note: This changes the default values for *datanucleus.autoCreateSchema*
and *datanucleus.fixedDatastore* in HiveConf.java, so I added a TODOC2.0 label.
*datanucleus.autoCreateSchema* just needs to be updated with its new default.
*datanucleus.fixedDatastore* is not documented yet, so it should be put in the
Metastore section of Configuration Properties with its original and new
defaults.
* [Configuration Properties -- MetaStore |
https://cwiki.apache.org/confluence/display/Hive/Configuration+Properties#ConfigurationProperties-MetaStore]
* [Configuration Properties -- MetaStore -- datanucleus.autoCreateSchema |
https://cwiki.apache.org/confluence/display/Hive/Configuration+Properties#ConfigurationProperties-datanucleus.autoCreateSchema]
*datanucleus.fixedDatastore* first appeared in HiveConf.java in 0.12.0 but
apparently existed as a configuration parameter before that -- see HIVE-1435
(committed in 0.6.0):
* [HIVE-1435 comment |
https://issues.apache.org/jira/browse/HIVE-1435?focusedCommentId=12882433&page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel#comment-12882433]
shows setting *datanucleus.fixedDatastore* to true
How should that be documented?
> 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, Metastore
> Affects Versions: 0.6.0
> Reporter: Edward Capriolo
> Assignee: Ashutosh Chauhan
> Priority: Minor
> Labels: TODOC2.0
> Fix For: 2.0.0
>
> Attachments: HIVE-1841.1.patch.txt, HIVE-1841.2.patch, HIVE-1841.patch
>
>
> 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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