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https://issues.apache.org/jira/browse/PHOENIX-5544?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16959500#comment-16959500
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Thomas D'Silva commented on PHOENIX-5544:
-----------------------------------------
For the case when you have a 4.14 client connecting to a 4.15 server (which has
never gotten a connection from a 4.15 client) in order to synchronously drop
child views you would have to bring back a lot of code that was removed.
We already block metadata operations such as adding a column to a base table
(since we longer propagate metadata child views) in order to enable rolling
back (see
[https://github.com/apache/phoenix/blob/f3f722e4f29293885f1854cca9dd4cd37e6ff085/phoenix-core/src/main/java/org/apache/phoenix/coprocessor/MetaDataEndpointImpl.java#L2478]).
I think we should just prevent dropping a base table that has child views if
the client version is less than 4.15. You will also have to modify the
{{ViewUtil.hasChildViews}} to check for the views in SYSTEM.CATALOG if the
upgrade code hasn't yet been run. B/W compatibility is hard :(
> Dropping a base table with cascade with an older client does not clear all
> child view metadata
> ----------------------------------------------------------------------------------------------
>
> Key: PHOENIX-5544
> URL: https://issues.apache.org/jira/browse/PHOENIX-5544
> Project: Phoenix
> Issue Type: Bug
> Affects Versions: 4.15.0, 5.1.0
> Reporter: Chinmay Kulkarni
> Assignee: Chinmay Kulkarni
> Priority: Major
> Fix For: 4.15.0, 5.1.0
>
>
> 1) Start the HBase server with 4.15.0 Phoenix
> 2) Connect with a 4.14 client
> 3) Create a base table and a view on top of the base table:
> {code:sql}
> CREATE TABLE IF NOT EXISTS Z_BASE_TABLE (ID INTEGER NOT NULL PRIMARY KEY,
> HOST VARCHAR(10), FLAG BOOLEAN);
> CREATE VIEW Z_VIEW1 (col1 INTEGER, col2 INTEGER, col3 INTEGER, col4 INTEGER,
> col5 INTEGER) AS SELECT * FROM Z_BASE_TABLE WHERE ID>10;
> {code}
> 4) Drop the base table with the cascade option:
> {code:sql}
> DROP TABLE Z_BASE_TABLE CASCADE;
> {code}
> 5) Metadata for Z_VIEW1 is still there in SYSTEM.CATALOG and should be
> removed when trying to recreate the same base table:
> {code:sql}
> CREATE TABLE IF NOT EXISTS Z_BASE_TABLE (ID INTEGER NOT NULL PRIMARY KEY,
> HOST VARCHAR(10), FLAG BOOLEAN);
> {code}
> 6) This should remove the metadata for Z_VIEW1, but it does not. In fact, you
> can now query Z_VIEW1 as if it was a valid view created on top of the new
> Z_BASE_TABLE, however there is no parent->child link i.e.:
> {code:sql}
> SELECT * FROM SYSTEM.CATALOG WHERE LINK_TYPE=4;
> {code}
> --> Returns no results.
> Effectively, Z_VIEW1 is sort of an "orphan" view with child->parent links but
> no parent->child links. This is dangerous if a user wants to drop and
> recreate a base table, but views from the previous lifetime of the base table
> can still be used to interact with the new base table.
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