[jira] [Comment Edited] (CASSANDRA-8928) Add downgradesstables

["Jeremy Hanna (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/CASSANDRA-8928?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15328361#comment-15328361 ] 

Jeremy Hanna edited comment on CASSANDRA-8928 at 6/13/16 9:50 PM:
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The primary use case for downgrading sstables is to abort an upgrade.  So for example, if you're on 2.1 and want to go to 2.2 or 3.x, the upgrade plan often includes a contingency plan to abort and revert back to the older version, including preserving data written while in the upgraded version.  While backwards compatible streaming (CASSANDRA-8110) is helpful in other scenarios, it wouldn't help for that use case.

Would it be possible to limit the implementation of this to the core sstable data file?  We could then have an offline downgrade sstable process that would convert to the older sstable data file and those files could be bulk loaded through that version's sstable loader into the reverted cluster.


was (Author: jeromatron):
The primary use case for downgrading sstables is to abort an upgrade.  So for example, if you're on 2.1 and want to go to 2.2 or 3.x, the upgrade plan often includes a contingency plan to abort and revert back to the older version, including preserving data written while in the upgraded version.  While backwards compatible streaming (CASSANDRA-8110) is helpful in other scenarios, it wouldn't help for that use case.

> Add downgradesstables
> ---------------------
>
>                 Key: CASSANDRA-8928
>                 URL: https://issues.apache.org/jira/browse/CASSANDRA-8928
>             Project: Cassandra
>          Issue Type: New Feature
>          Components: Tools
>            Reporter: Jeremy Hanna
>            Assignee: Kaide Mu
>            Priority: Minor
>              Labels: gsoc2016, mentor
>
> As mentioned in other places such as CASSANDRA-8047 and in the wild, sometimes you need to go back.  A downgrade sstables utility would be nice for a lot of reasons and I don't know that supporting going back to the previous major version format would be too much code since we already support reading the previous version.



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