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https://issues.apache.org/jira/browse/HADOOP-14335?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15979872#comment-15979872
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Steve Loughran commented on HADOOP-14335:
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if the version no is change, the current clients will all refuse to play; it
assumes no backwards compatibility. Here it is clearly going to be needed
adding a .minor version marker to indicate "schema change, compatible across
versions of same major marker" would let you do smaller backwards compatible
tweaks.
Schema upgrade sounds like some runbook story + maybe a new entry point/command
with some {{--yes}} confirm option. Deleting the schema and rebuilding probably
is the simplest tactic for now, though for authoritative mode we may need to
think of whether we need to manage any sync/shutdown just to be sure all is well
now, FWIW, no ASF code has shipped the schema, so in theory we could be
guilt-free about changing things.
> Improve DynamoDB schema update story
> ------------------------------------
>
> Key: HADOOP-14335
> URL: https://issues.apache.org/jira/browse/HADOOP-14335
> Project: Hadoop Common
> Issue Type: Sub-task
> Components: fs/s3
> Affects Versions: HADOOP-13345
> Reporter: Sean Mackrory
> Assignee: Sean Mackrory
>
> On HADOOP-13760 I'm realizing that changes to the DynamoDB schema aren't
> great to deal with. Currently a build of Hadoop is hard-coded to a specific
> schema version. So if you upgrade from one to the next you have to upgrade
> everything (and then update the version in the table - which we don't have a
> tool or document for) before you can keep using S3Guard. We could possibly
> also make the definition of compatibility a bit more flexible, but it's going
> to be very tough to do that without knowing what kind of future schema
> changes we might want ahead of time.
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