anishshri-db commented on code in PR #44542:
URL: https://github.com/apache/spark/pull/44542#discussion_r1438964350
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sql/core/src/main/scala/org/apache/spark/sql/execution/streaming/statefulOperators.scala:
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@@ -434,22 +434,26 @@ case class StateStoreRestoreExec(
numColsPrefixKey = 0,
session.sessionState,
Some(session.streams.stateStoreCoordinator)) { case (store, iter) =>
- val hasInput = iter.hasNext
- if (!hasInput && keyExpressions.isEmpty) {
- // If our `keyExpressions` are empty, we're getting a global
aggregation. In that case
- // the `HashAggregateExec` will output a 0 value for the partial
merge. We need to
- // restore the value, so that we don't overwrite our state with a 0
value, but rather
- // merge the 0 with existing state.
- store.iterator().map(_.value)
- } else {
- iter.flatMap { row =>
- val key = stateManager.getKey(row.asInstanceOf[UnsafeRow])
- val restoredRow = stateManager.get(store, key)
- val outputRows = Option(restoredRow).toSeq :+ row
- numOutputRows += outputRows.size
- outputRows
- }
+ val hasInput = iter.hasNext
+ val result = if (!hasInput && keyExpressions.isEmpty) {
+ // If our `keyExpressions` are empty, we're getting a global
aggregation. In that case
+ // the `HashAggregateExec` will output a 0 value for the partial
merge. We need to
+ // restore the value, so that we don't overwrite our state with a 0
value, but rather
+ // merge the 0 with existing state.
+ store.iterator().map(_.value)
+ } else {
+ iter.flatMap { row =>
+ val key = stateManager.getKey(row.asInstanceOf[UnsafeRow])
+ val restoredRow = stateManager.get(store, key)
+ val outputRows = Option(restoredRow).toSeq :+ row
+ numOutputRows += outputRows.size
+ outputRows
}
+ }
+ // SPARK-46547 - Release any locks/resources if required, to prevent
+ // deadlocks with the maintenance thread.
+ store.abort()
Review Comment:
I believe this issue always existed. In the common case, we won't see this
that often though. Basically the restore is followed by the save operator which
opens the db instance in read-write mode, in the context of the same task
thread. At the end of the save operator, we would always release the instance
lock. For the `ReadStateStore` invocations though, there is no such
functionality (we only abort on task failure) - so the interleaving of the
maintenance thread error case (also likely rare) and the execution of
StateStoreRDD for the `save` operator causes this deadlock
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