[HIVE-9223] HiveServer2 on Tez doesn't support concurrent queries within one session

• Type: Bug
• Status: Open
• Priority: Major
• Resolution: Unresolved
• Component/s: HiveServer2
• Assignee: Unassigned
• Reporter: Pala M Muthaia
• Created: 30/Dec/14 00:36
• Updated: 20/Nov/19 00:54

Description

When a user submits multiple queries in the same HS2 session (using thrift interface) concurrently, the query goes through the same TezSessionState and ends up being submitted to the same Tez AM, and the second query fails with the error "App master already running a DAG"

Is this by design? I looked into the code, and the comments as well as the code suggest support only for serial execution of queries within the same HiveServer2 session (on tez).

This works for CLI environment but in a server, it is plausible that client sends multiple concurrent queries under the same session (e.g: a web app that executes queries for user, such as Cloudera Hue). So shouldn't HS2 on Tez implementation support concurrent queries?