Made get_conn in JdbcHook threadsafe to avoid OSError: JVM is already started #44718
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…is already started when used in multithreaded environment
potiuk
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Dec 6, 2024
potiuk
reviewed
Dec 11, 2024
…d by Jarek instead of wrapt synchronized decorator
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@potiuk modified the code as you asked I think this one is ok now |
potiuk
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Dec 13, 2024
LefterisXefteris
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Jan 5, 2025
… started (apache#44718) * refactor: Made get_conn in JdbcHook threadsafe to avoid OSError: JVM is already started when used in multithreaded environment * Refactor: removed commented code * refactor: Reorganized imports * refactor: Added white line * refactor: Fixed static checks test JdbcHook * refactor: Added white line * refactor: Refactored JdbcHook get_conn method using RLock as suggested by Jarek instead of wrapt synchronized decorator --------- Co-authored-by: David Blain <david.blain@infrabel.be>
got686-yandex
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Jan 30, 2025
… started (apache#44718) * refactor: Made get_conn in JdbcHook threadsafe to avoid OSError: JVM is already started when used in multithreaded environment * Refactor: removed commented code * refactor: Reorganized imports * refactor: Added white line * refactor: Fixed static checks test JdbcHook * refactor: Added white line * refactor: Refactored JdbcHook get_conn method using RLock as suggested by Jarek instead of wrapt synchronized decorator --------- Co-authored-by: David Blain <david.blain@infrabel.be>
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When using our in house IterableOperator to allow easy multithreading with operators within the same worker, we discovered a thread safety issue with the JdbcHook. As multiple threads where trying to get a connection through the jaydebeapi libary, we sometimes got random "OSError: JVM is already started" errors, due to the high concurrency/parallelism, something you won't experience if you do the same using the expand mapped task as each task instance is then run on a different Python process.
To fix the issue I made the get_conn method of the JdbcHook synchronized and added a unit test which simulates the behaviour to avoid regression in the future so this is well documented through a test.
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