Hi all, During the investigation of a metaspace memory leak issue in Flink IcebergSource ( https://github.com/apache/iceberg/pull/11073 ), a discussion with @pvary revealed that *ThreadPools.newWorkerPool* currently registers a Shutdown Hook via ExitingExecutorService for all created thread pools. While this ensures graceful shutdown of the pools when the JVM exits, it might lead to unnecessary Shutdown Hook accumulation, especially when the pool is explicitly closed within the application's lifecycle.
I propose to *modify ThreadPools.newWorkerPool to not register a Shutdown Hook by default*. This would prevent potential issues where developers might unintentionally register numerous Shutdown Hooks when using ThreadPools.newWorkerPool for short-lived thread pools. To retain the existing functionality for long-lived thread pools that require a Shutdown Hook, I suggest introducing a new, more descriptive function, such as *newExitingWorkerPool*. This function would explicitly create thread pools that are registered with a Shutdown Hook. *This change might potentially impact users who rely on the implicit Shutdown Hook registration provided by the current ThreadPools.newWorkerPool implementation.* I would like to gather feedback from the community regarding this proposed change, especially regarding potential compatibility concerns. Best regards, Feng Jiajie
