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https://issues.apache.org/jira/browse/HIVE-11402?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15375303#comment-15375303
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Thejas M Nair commented on HIVE-11402:
--------------------------------------

[~sershe] Can you also add a simple test to ensure that the queries get 
serialized ? (So we know this feature works :p )

Something like - 
HiveStatement stmt1 = (HiveStatement)  con.createStatement();
HiveStatement stmt2 = (HiveStatement) con.createStatement();
stmt1.executeAsync(create table t(i int));
stmt1.executeAsync(insert into t select sleepUDF(1))
stmt2.executeAsync(select * from t ) 
verify above statement returned 1 row





> HS2 - add an option to disallow parallel query execution within a single 
> Session
> --------------------------------------------------------------------------------
>
>                 Key: HIVE-11402
>                 URL: https://issues.apache.org/jira/browse/HIVE-11402
>             Project: Hive
>          Issue Type: Bug
>          Components: HiveServer2
>            Reporter: Thejas M Nair
>            Assignee: Sergey Shelukhin
>         Attachments: HIVE-11402.01.patch, HIVE-11402.02.patch, 
> HIVE-11402.03.patch, HIVE-11402.patch
>
>
> HiveServer2 currently allows concurrent queries to be run in a single 
> session. However, every HS2 session has  an associated SessionState object, 
> and the use of SessionState in many places assumes that only one thread is 
> using it, ie it is not thread safe.
> There are many places where SesssionState thread safety needs to be 
> addressed, and until then we should serialize all query execution for a 
> single HS2 session. -This problem can become more visible with HIVE-4239 now 
> allowing parallel query compilation.-
> Note that running queries in parallel for single session is not 
> straightforward  with jdbc, you need to spawn another thread as the 
> Statement.execute calls are blocking. I believe ODBC has non blocking query 
> execution API, and Hue is another well known application that shares sessions 
> for all queries that a user runs.



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