Marton Bod created HIVE-23283:
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Summary: Generate random temp ID for lock enqueue and commitTxn
Key: HIVE-23283
URL: https://issues.apache.org/jira/browse/HIVE-23283
Project: Hive
Issue Type: Improvement
Reporter: Marton Bod
Assignee: Marton Bod
In order to optimize the S4U scope of enqueue lock and commitTxn, currently a
hardcoded constant (-1) is used to first insert all the lock and ws entries
with a temporary lockID/commitID. However, in a concurrent environment this
seems to cause some performance degradation (and deadlock issues with some
rdbms) as multiple concurrent transactions are trying to insert rows with the
same primary key (e.g. (-1, 1), (-1, 2), (-1, 3), .. etc. for (extID/intID) in
HIVE_LOCKS). The proposed solution is to replace the constant with a random
generated negative number, which seems to resolve this issue.
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