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Sreekanth Ramakrishnan commented on HADOOP-6105: ------------------------------------------------ Took a look at the patch following are the comments which I had on the same: * {{org.apache.hadoop.conf.Configuration.addDeprecation(String, String[])}} should be made public so classes can access it. * We dont need to call {{Class.newInstance()}} as we assume that child classes would have static block which would add deprecated keys, so during class loading we will take care of it. * We should make the process deprecation and data structures all multi-threaded. * Finally, we should handle the cases where one or all of the keys which are defined in extra.conf are not present in class path. I would suggest suppressing exception and logging it in debug mode. * lastly move the loaded deprecation boolean as last line in process deprecation. We should also take care that deprecated keys are not going to be reloaded and reprocessed with {{Configuration.reload()}} method. * Define the key in core-default.xml and make the same final. > Provide a way to automatically handle backward compatibility of deprecated > keys > ------------------------------------------------------------------------------- > > Key: HADOOP-6105 > URL: https://issues.apache.org/jira/browse/HADOOP-6105 > Project: Hadoop Common > Issue Type: Improvement > Components: conf > Reporter: Hemanth Yamijala > Assignee: V.V.Chaitanya Krishna > Attachments: HADOOP-6105-1.patch, HADOOP-6105-2.patch, > HADOOP-6105-3.patch, HADOOP-6105-4.patch, HADOOP-6105-5.patch, > HADOOP-6105-6.patch, HADOOP-6105.patch, HADOOP-6105.patch > > > There are cases when we have had to deprecate configuration keys. Use cases > include, changing the names of variables to better match intent, splitting a > single parameter into two - for maps, reduces etc. > In such cases, we typically provide a backwards compatible option for the old > keys. The handling of such cases might typically be common enough to actually > add support for it in a generic fashion in the Configuration class. Some > initial discussion around this started in HADOOP-5919, but since the project > split happened in between we decided to open this issue to fix it in common. -- This message is automatically generated by JIRA. - You can reply to this email to add a comment to the issue online.