[
https://issues.apache.org/jira/browse/PHOENIX-3534?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15983192#comment-15983192
]
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.
--
This message was sent by Atlassian JIRA
(v6.3.15#6346)
