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https://issues.apache.org/jira/browse/PHOENIX-3534?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16450225#comment-16450225
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Thomas D'Silva commented on PHOENIX-3534:
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[~jamestaylor] , [~lhofhansl]
Do we want to be able to rollback a release that contains this feature? If so
we will still have to propagate metadata changes from the base table to all the
child views and also ensure SYSTEM.CATALOG does not split. Once we stop
propagating metadata changes to child views we won't be able to rollback, since
the metadata of the view will only contain columns that were created in the
view (and will not contain any parent table columns).
So should we continue propagating metadata changes to child views for one more
release?
> Support multi region SYSTEM.CATALOG table
> -----------------------------------------
>
> Key: PHOENIX-3534
> URL: https://issues.apache.org/jira/browse/PHOENIX-3534
> Project: Phoenix
> Issue Type: Bug
> Reporter: James Taylor
> Assignee: Thomas D'Silva
> Priority: Major
> Attachments: PHOENIX-3534-wip.patch
>
>
> Currently Phoenix requires that the SYSTEM.CATALOG table is single region
> based on the server-side row locks being held for operations that impact a
> table and all of it's views. For example, adding/removing a column from a
> base table pushes this change to all views.
> As an alternative to making the SYSTEM.CATALOG transactional (PHOENIX-2431),
> when a new table is created we can do a lazy cleanup of any rows that may be
> left over from a failed DDL call (kudos to [~lhofhansl] for coming up with
> this idea). To implement this efficiently, we'd need to also do PHOENIX-2051
> so that we can efficiently find derived views.
> The implementation would rely on an optimistic concurrency model based on
> checking our sequence numbers for each table/view before/after updating. Each
> table/view row would be individually locked for their change (metadata for a
> view or table cannot span regions due to our split policy), with the sequence
> number being incremented under lock and then returned to the client.
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