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https://issues.apache.org/jira/browse/SPARK-18389?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15652039#comment-15652039
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Nattavut Sutyanyong edited comment on SPARK-18389 at 11/9/16 9:10 PM:
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In CREATE VIEW, if we will check that the objects in the view definition need
to exist in the Catalog, then CREATE VIEW cannot create a cyclic reference. It
is only the ALTER VIEW that can create this problem. We will need to expand the
objects referenced and any descendant views recursively during the processing
of ALTER VIEW.
I have a side question regarding how Spark deals with the concurrency and
locking of catalog changes.
{code}
time | session 1 | session 2
T1 | CREATE TAB T1 |
T2 | CREATE VIEW V1 -> T1 |
T3 | CREATE VIEW V2 -> V1 |
T4 | CREATE VIEW V3 -> V2 | ALTER VIEW V2-> V3
{code}
Does the current code have a mechanism to lock the entry of V2 during the
compilation of VIEW V3 in time T4 to prevent any change made to the definition
of V2 in session 2?
was (Author: nsyca):
In CREATE VIEW, if we will check that the objects in the view definition need
to exist in the Catalog, then CREATE VIEW cannot create a cyclic reference. It
is only the ALTER VIEW that can create this problem. We will need to expand the
objects referenced and any descendant views recursively during the processing
of ALTER VIEW.
I have a side question regarding how Spark deals with the concurrency and
locking of catalog changes.
````
time | session 1 | session 2
T1 | CREATE TAB T1 |
T2 | CREATE VIEW V1 -> T1 |
T3 | CREATE VIEW V2 -> V1 |
T4 | CREATE VIEW V3 -> V2 | ALTER VIEW V2-> V3
````
Does the current code have a mechanism to lock the entry of V2 during the
compilation of VIEW V3 in time T4 to prevent any change made to the definition
of V2 in session 2?
> Disallow cyclic view reference
> ------------------------------
>
> Key: SPARK-18389
> URL: https://issues.apache.org/jira/browse/SPARK-18389
> Project: Spark
> Issue Type: Sub-task
> Components: SQL
> Reporter: Reynold Xin
>
> The following should not be allowed:
> {code}
> CREATE VIEW testView AS SELECT id FROM jt
> CREATE VIEW testView2 AS SELECT id FROM testView
> ALTER VIEW testView AS SELECT * FROM testView2
> {code}
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