Zhihua Deng created HIVE-28545:
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Summary: Remove global lock on HMSHandler.getMSForConf which is
prone to deadlock
Key: HIVE-28545
URL: https://issues.apache.org/jira/browse/HIVE-28545
Project: Hive
Issue Type: Bug
Security Level: Public (Viewable by anyone)
Components: Standalone Metastore
Reporter: Zhihua Deng
Assignee: Zhihua Deng
We add the global lock on HMSHandler.getMSForConf by HIVE-27117, which is aim
to address the flaky test:
TestCompactionMetrics.testInitiatorFailuresCountedCorrectly, however this
global lock could contribute to another deadlock problem. Imaging this, if
there is no idle connection in the connection pool, HMSHandler needs getMS to
commit or. rollback the transaction, a new client chimes in and takes over this
global lock to initialize the ObjectStore, the initialization will be pending
as there is no available connection, which prevents others to get the global
lock to free the occupied connection, I wrote a test to demonstrate this case.
This global lock could result to performance penalty which can block other
clients in concurrent workloads. In worst cases, it can make other clients read
timeout.
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