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https://issues.apache.org/jira/browse/HIVE-21125?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Barnabas Maidics updated HIVE-21125:
------------------------------------
    Description: 
Dropping a table leads to undefined behavior when that table is the source of 
an existing materialized view. The following behavior is observed:
 
 * Table still appears in 'show tables' despite not being in metastore
 * Actions on table hang and then display a "could not fetch table" error
 * Rebuilding any dependent materialized view has same error

It seems that the root cause is the fact that users are allowed to issue a DROP 
TABLE command against a table even if there is a materialized view using this 
table at the time. This is not something I have seen other query languages 
permit. 

Repro steps: Launch these commands from any Hive 3 client:
{code:java}
create table footable (id int); insert into footable values (1), (2), (3);
create materialized view mv_footable as select count(*) from footable;
drop table footable;

--These lines have unexpected behavior
show tables;
select * from footable;
alter materialized view mv_footable rebuild;{code}

  was:
Dropping a table leads to undefined behavior when that table is the source of 
an existing materialized view. The following behavior is observed:
  
 * Table still appears in 'show tables' despite not being in metastore
 * Actions on table hang and then display a "could not fetch table" error
 * Rebuilding any dependent materialized view has same error

It seems that the root cause is the fact that users are allowed to issue a DROP 
TABLE command against a table even if there is a materialized view using this 
table at the time. This is not something I have seen other query languages 
permit. 

Repro steps: Launch these commands from any Hive 3 client:
{code:java}
create table footable (id int); insert into footable values (1), (2), (3);
create materialized view mv_footable as select count(*) from footable;
drop table footable;

--These lines have unexpected behavior
show tables;
select * from footable;
alter materialized view mv_footable rebuild;{code}


> Hive does not check for dependent materialized views when issuing a DROP 
> TABLE command
> --------------------------------------------------------------------------------------
>
>                 Key: HIVE-21125
>                 URL: https://issues.apache.org/jira/browse/HIVE-21125
>             Project: Hive
>          Issue Type: Bug
>          Components: Materialized views
>    Affects Versions: 3.1.0
>            Reporter: Taylor Cox
>            Priority: Major
>
> Dropping a table leads to undefined behavior when that table is the source of 
> an existing materialized view. The following behavior is observed:
>  
>  * Table still appears in 'show tables' despite not being in metastore
>  * Actions on table hang and then display a "could not fetch table" error
>  * Rebuilding any dependent materialized view has same error
> It seems that the root cause is the fact that users are allowed to issue a 
> DROP TABLE command against a table even if there is a materialized view using 
> this table at the time. This is not something I have seen other query 
> languages permit. 
> Repro steps: Launch these commands from any Hive 3 client:
> {code:java}
> create table footable (id int); insert into footable values (1), (2), (3);
> create materialized view mv_footable as select count(*) from footable;
> drop table footable;
> --These lines have unexpected behavior
> show tables;
> select * from footable;
> alter materialized view mv_footable rebuild;{code}



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