sumeetgajjar opened a new pull request #32114:
URL: https://github.com/apache/spark/pull/32114
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### What changes were proposed in this pull request?
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This patch proposes a fix to prevent triggering BlockManager reregistration
while `StopExecutor` msg is in-flight.
It adds a Cache of recently removed executors on Driver. During the
registration in `BlockManagerMasterEndpoint` if the BlockManager belongs to a
recently removed executor, we return None indicating the registration is
ignored since the executor will be shutting down soon.
On `BlockManagerHeartbeat`, if the BlockManager belongs to a recently
removed executor, we return true indicating the driver knows about it, thereby
preventing reregisteration.
### Why are the changes needed?
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This changes are needed since BlockManager reregistration while executor is
shutting down causes inconsistent bookkeeping of executors in Spark.
Consider the following scenario:
- `CoarseGrainedSchedulerBackend` issues async `StopExecutor` on
executorEndpoint
- `CoarseGrainedSchedulerBackend` removes that executor from Driver's
internal data structures and publishes `SparkListenerExecutorRemoved` on the
`listenerBus`.
- Executor has still not processed `StopExecutor` from the Driver
- Driver receives heartbeat from the Executor, since it cannot find the
`executorId` in its data structures, it responds with
`HeartbeatResponse(reregisterBlockManager = true)`
- `BlockManager` on the Executor reregisters with the `BlockManagerMaster`
and `SparkListenerBlockManagerAdded` is published on the `listenerBus`
- Executor starts processing the `StopExecutor` and exits
- `AppStatusListener` picks the `SparkListenerBlockManagerAdded` event and
updates `AppStatusStore`
- `statusTracker.getExecutorInfos` refers `AppStatusStore` to get the list
of executors which returns the dead executor as alive.
### Does this PR introduce _any_ user-facing change?
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No
### How was this patch tested?
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Added new unit tests
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