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https://issues.apache.org/jira/browse/HIVE-11402?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Sergey Shelukhin updated HIVE-11402:
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Attachment: HIVE-11402.patch
Simple patch that adds a semaphore to acquire/release methods, configurable and
on by default (parallel operations are off, rather). [~thejas] can you take a
look? Esp. wrt what is an operation and what isn't, e.g. should fetching
results be allowed to run in parallel with other things?
I will post an RB shortly
> HS2 - 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.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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