Vaibhav Gumashta created HIVE-8761:
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Summary: JDOPersistenceManager creation should be controlled by at
the Server level and not Thread level
Key: HIVE-8761
URL: https://issues.apache.org/jira/browse/HIVE-8761
Project: Hive
Issue Type: Bug
Components: Metastore
Affects Versions: 0.15.0
Reporter: Vaibhav Gumashta
Assignee: Vaibhav Gumashta
When using JDO, we create a thread local RawStore (ObjectStore) object in each
metastore thread. This leads to creation of a new JDOPersistenceManager per
thread which are cached in JDOPersistanceManagerFactory. To remove
JDOPersistenceManager from JDOPersistanceManagerFactory, an explicit
JDOPersistenceManager.close needs to be called.
This is a bad candidate for thread local as the effective object destruction
requires the application to call close. So, when metastore threads are killed
by the threadpool, this object will never be removed from the
JDOPersistanceManagerFactory cache.
We fixed this for HiveServer2 using embedded metastore (HIVE-7353) by
customizing the GC collection of the dying thread, but I believe a better and
more efficient solution is to pool JDOPersistenceManager objects and let each
thread get an object for its use from the pool.
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