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https://issues.apache.org/jira/browse/HIVE-12790?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15086001#comment-15086001
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Thejas M Nair commented on HIVE-12790:
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TaskRunner should not be creating a new SessionState object. The SessionState
object is expected to be used for the entire hive session. The right fix would
be to not create additional SessionState in TaskRunner (assuming thats
happening).
> Metastore connection leaks in HiveServer2
> -----------------------------------------
>
> Key: HIVE-12790
> URL: https://issues.apache.org/jira/browse/HIVE-12790
> Project: Hive
> Issue Type: Bug
> Components: HiveServer2
> Affects Versions: 1.1.0
> Reporter: Naveen Gangam
> Assignee: Naveen Gangam
> Attachments: HIVE-12790.patch, snippedLog.txt
>
>
> HiveServer2 keeps opening new connections to HMS each time it launches a
> task. These connections do not appear to be closed when the task completes
> thus causing a HMS connection leak. "lsof" for the HS2 process shows
> connections to port 9083.
> {code}
> 2015-12-03 04:20:56,352 INFO [HiveServer2-Background-Pool: Thread-424756()]:
> ql.Driver (SessionState.java:printInfo(558)) - Launching Job 11 out of 41
> 2015-12-03 04:20:56,354 INFO [Thread-405728()]: hive.metastore
> (HiveMetaStoreClient.java:open(311)) - Trying to connect to metastore with
> URI thrift://<anonymizedURL>:9083
> 2015-12-03 04:20:56,360 INFO [Thread-405728()]: hive.metastore
> (HiveMetaStoreClient.java:open(351)) - Opened a connection to metastore,
> current connections: 14824
> 2015-12-03 04:20:56,360 INFO [Thread-405728()]: hive.metastore
> (HiveMetaStoreClient.java:open(400)) - Connected to metastore.
> ....
> 2015-12-03 04:21:06,355 INFO [HiveServer2-Background-Pool: Thread-424756()]:
> ql.Driver (SessionState.java:printInfo(558)) - Launching Job 12 out of 41
> 2015-12-03 04:21:06,357 INFO [Thread-405756()]: hive.metastore
> (HiveMetaStoreClient.java:open(311)) - Trying to connect to metastore with
> URI thrift://<anonymizedURL>:9083
> 2015-12-03 04:21:06,362 INFO [Thread-405756()]: hive.metastore
> (HiveMetaStoreClient.java:open(351)) - Opened a connection to metastore,
> current connections: 14825
> 2015-12-03 04:21:06,362 INFO [Thread-405756()]: hive.metastore
> (HiveMetaStoreClient.java:open(400)) - Connected to metastore.
> ...
> 2015-12-03 04:21:08,357 INFO [HiveServer2-Background-Pool: Thread-424756()]:
> ql.Driver (SessionState.java:printInfo(558)) - Launching Job 13 out of 41
> 2015-12-03 04:21:08,360 INFO [Thread-405782()]: hive.metastore
> (HiveMetaStoreClient.java:open(311)) - Trying to connect to metastore with
> URI thrift://<anonymizedURL>:9083
> 2015-12-03 04:21:08,364 INFO [Thread-405782()]: hive.metastore
> (HiveMetaStoreClient.java:open(351)) - Opened a connection to metastore,
> current connections: 14826
> 2015-12-03 04:21:08,365 INFO [Thread-405782()]: hive.metastore
> (HiveMetaStoreClient.java:open(400)) - Connected to metastore.
> ...
> {code}
> The TaskRunner thread starts a new SessionState each time, which creates a
> new connection to the HMS (via Hive.get(conf).getMSC()) that is never closed.
> Even SessionState.close(), currently not being called by the TaskRunner
> thread, does not close this connection.
> Attaching a anonymized log snippet where the number of HMS connections
> reaches north of 25000+ connections.
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