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https://issues.apache.org/jira/browse/HIVE-14296?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15387699#comment-15387699
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Naveen Gangam commented on HIVE-14296:
--------------------------------------
[~mohitsabharwal] You are right, they appear to be treated the same. I thought
the OPEN_CONNECTIONS metric was more inline with the log record that indicated
number of connections to the HMS
{{INFO hive.metastore: [HiveServer2-Handler-Pool: Thread-34]: Opened a
connection to metastore, current connections: 2}}
As for the other concern about the metric being doubly incremented, my
understanding is the same as [~szehon]'s. I thought we do not use thrift
between HS2 and HMS in embedded mode. If true, would the HMS side count ever be
incremented beyond 0?
[~szehon] I agree, I dont know how I missed that. The decrement should have
been conditionalized. But since we propose to make a change to use the
getOpenSessionCount(), this should already be accounted for.
To summarize the actions
1) Eliminate the sessionCount counter and use getOpenSessionCount() instead.
Test and upload a new patch.
2) Test metric values for OPEN_CONNECTIONS when HMS is running in embedded mode
within HS2 process.
Sound good?
> Session count is not decremented when HS2 clients do not shutdown cleanly.
> --------------------------------------------------------------------------
>
> Key: HIVE-14296
> URL: https://issues.apache.org/jira/browse/HIVE-14296
> Project: Hive
> Issue Type: Bug
> Components: HiveServer2
> Affects Versions: 2.0.0
> Reporter: Naveen Gangam
> Assignee: Naveen Gangam
> Attachments: HIVE-14296.patch
>
>
> When a JDBC client like beeline abruptly disconnects from HS2, the session
> gets closed on the serverside but the session count reported in the logs is
> incorrect. It never gets decremented.
> For example, I created 6 connections from the same instance of beeline to HS2.
> {code}
> 2016-07-20T15:05:17,987 INFO [HiveServer2-Handler-Pool: Thread-40]
> thrift.ThriftCLIService: Opened a session SessionHandle
> [28b225ee-204f-4b3e-b4fd-0039ef8e276e], current sessions: 1
> .....
> 2016-07-20T15:05:24,239 INFO [HiveServer2-Handler-Pool: Thread-45]
> thrift.ThriftCLIService: Opened a session SessionHandle
> [1d267de8-ff9a-4e76-ac5c-e82c871588e7], current sessions: 2
> .....
> 2016-07-20T15:05:25,710 INFO [HiveServer2-Handler-Pool: Thread-50]
> thrift.ThriftCLIService: Opened a session SessionHandle
> [04d53deb-8965-464b-aa3f-7042304cfb54], current sessions: 3
> .....
> 2016-07-20T15:05:26,795 INFO [HiveServer2-Handler-Pool: Thread-55]
> thrift.ThriftCLIService: Opened a session SessionHandle
> [b4bb8b86-74e1-4e3c-babb-674d34ad1caf], current sessions: 4
> 2016-07-20T15:05:28,160 INFO [HiveServer2-Handler-Pool: Thread-60]
> thrift.ThriftCLIService: Opened a session SessionHandle
> [6d3c3ed9-fadb-4673-8c15-3315b7e2995d], current sessions: 5
> .....
> 2016-07-20T15:05:29,136 INFO [HiveServer2-Handler-Pool: Thread-65]
> thrift.ThriftCLIService: Opened a session SessionHandle
> [88b630c0-f272-427d-8263-febfe2222f8d], current sessions: 6
> {code}
> When I CNTRL-C the beeline process, in the HS2 logs I see
> {code}
> 2016-07-20T15:11:37,858 INFO [HiveServer2-Handler-Pool: Thread-55]
> thrift.ThriftCLIService: Session disconnected without closing properly.
> 2016-07-20T15:11:37,858 INFO [HiveServer2-Handler-Pool: Thread-40]
> thrift.ThriftCLIService: Session disconnected without closing properly.
> 2016-07-20T15:11:37,858 INFO [HiveServer2-Handler-Pool: Thread-65]
> thrift.ThriftCLIService: Session disconnected without closing properly.
> 2016-07-20T15:11:37,858 INFO [HiveServer2-Handler-Pool: Thread-60]
> thrift.ThriftCLIService: Session disconnected without closing properly.
> 2016-07-20T15:11:37,859 INFO [HiveServer2-Handler-Pool: Thread-50]
> thrift.ThriftCLIService: Session disconnected without closing properly.
> 2016-07-20T15:11:37,859 INFO [HiveServer2-Handler-Pool: Thread-45]
> thrift.ThriftCLIService: Session disconnected without closing properly.
> 2016-07-20T15:11:37,859 INFO [HiveServer2-Handler-Pool: Thread-55]
> thrift.ThriftCLIService: Closing the session: SessionHandle
> [b4bb8b86-74e1-4e3c-babb-674d34ad1caf]
> 2016-07-20T15:11:37,859 INFO [HiveServer2-Handler-Pool: Thread-40]
> thrift.ThriftCLIService: Closing the session: SessionHandle
> [28b225ee-204f-4b3e-b4fd-0039ef8e276e]
> 2016-07-20T15:11:37,859 INFO [HiveServer2-Handler-Pool: Thread-65]
> thrift.ThriftCLIService: Closing the session: SessionHandle
> [88b630c0-f272-427d-8263-febfe2222f8d]
> 2016-07-20T15:11:37,859 INFO [HiveServer2-Handler-Pool: Thread-60]
> thrift.ThriftCLIService: Closing the session: SessionHandle
> [6d3c3ed9-fadb-4673-8c15-3315b7e2995d]
> 2016-07-20T15:11:37,859 INFO [HiveServer2-Handler-Pool: Thread-45]
> thrift.ThriftCLIService: Closing the session: SessionHandle
> [1d267de8-ff9a-4e76-ac5c-e82c871588e7]
> 2016-07-20T15:11:37,859 INFO [HiveServer2-Handler-Pool: Thread-50]
> thrift.ThriftCLIService: Closing the session: SessionHandle
> [04d53deb-8965-464b-aa3f-7042304cfb54]
> {code}
> The next time I connect to HS2 via beeline, I see
> {code}
> 2016-07-20T15:14:33,679 INFO [HiveServer2-Handler-Pool: Thread-50]
> thrift.ThriftCLIService: Client protocol version: HIVE_CLI_SERVICE_PROTOCOL_V8
> 2016-07-20T15:14:33,710 INFO [HiveServer2-Handler-Pool: Thread-50]
> session.SessionState: Created HDFS directory:
> /tmp/hive/hive/d47759e8-df3a-4504-9f28-99ff5247352c
> 2016-07-20T15:14:33,725 INFO [HiveServer2-Handler-Pool: Thread-50]
> session.SessionState: Created local directory:
> /var/folders/_3/0w477k4j5bjd6h967rw4vflw0000gp/T/ngangam/d47759e8-df3a-4504-9f28-99ff5247352c
> 2016-07-20T15:14:33,735 INFO [HiveServer2-Handler-Pool: Thread-50]
> session.SessionState: Created HDFS directory:
> /tmp/hive/hive/d47759e8-df3a-4504-9f28-99ff5247352c/_tmp_space.db
> 2016-07-20T15:14:33,737 INFO [HiveServer2-Handler-Pool: Thread-50]
> session.HiveSessionImpl: Operation log session directory is created:
> /var/folders/_3/0w477k4j5bjd6h967rw4vflw0000gp/T/ngangam/operation_logs/d47759e8-df3a-4504-9f28-99ff5247352c
> 2016-07-20T15:14:33,737 INFO [HiveServer2-Handler-Pool: Thread-50]
> thrift.ThriftCLIService: Opened a session SessionHandle
> [d47759e8-df3a-4504-9f28-99ff5247352c], current sessions: 7
> {code}
> So while the sessions itself are closed and cleaned up, the session count
> reported is not accurate.
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