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https://issues.apache.org/jira/browse/PHOENIX-3534?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15983192#comment-15983192
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James Taylor commented on PHOENIX-3534:
---------------------------------------

One more corner case: once a view has deleted columns from its parent table(s), 
it's considered as "diverged". I think we can detect this if the view has any 
excluded columns. In this case, we should no longer add columns from the parent 
tables created after this. I think we can base this on the earliest timestamp 
of the excluded column key value. This is conceptually equivalent to creating 
the view without doing a SELECT *, but instead only selecting a subset of 
columns, like this:
{code}
CREATE VIEW v AS SELECT a,c FROM t;
{code}
In this case, columns added to {{t}} should not impact the view {{v}} at all.

> 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: churro morales
>
> 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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