Github user kiszk commented on a diff in the pull request:
https://github.com/apache/spark/pull/22233#discussion_r213009058
--- Diff:
sql/core/src/main/scala/org/apache/spark/sql/execution/command/ddl.scala ---
@@ -671,7 +674,7 @@ case class AlterTableRecoverPartitionsCommand(
val value = ExternalCatalogUtils.unescapePathName(ps(1))
if (resolver(columnName, partitionNames.head)) {
scanPartitions(spark, fs, filter, st.getPath, spec ++
Map(partitionNames.head -> value),
- partitionNames.drop(1), threshold, resolver)
+ partitionNames.drop(1), threshold, resolver,
listFilesInParallel = false)
--- End diff --
Thank you attaching the stack trace. I have just looked at it. It looks
strange to me. Every thread is `waiting for`. No blocker is there, only one
`locked` exists.
In typical case, a deadlock occurs due to existence of blocker as attached
stack trace in #22221
I will investigate it furthermore tomorrow if we need to use this
implementation instead of reverting it to the original implementation to use
Scala parallel collection.
```
...
- parking to wait for <0x0000000793c0d610> (a
scala.concurrent.impl.Promise$CompletionLatch)
at java.util.concurrent.locks.LockSupport.park(LockSupport.java:175)
at
java.util.concurrent.locks.AbstractQueuedSynchronizer.parkAndCheckInterrupt(AbstractQueuedSynchronizer.java:836)
at
java.util.concurrent.locks.AbstractQueuedSynchronizer.doAcquireSharedInterruptibly(AbstractQueuedSynchronizer.java:997)
at
java.util.concurrent.locks.AbstractQueuedSynchronizer.acquireSharedInterruptibly(AbstractQueuedSynchronizer.java:1304)
at
scala.concurrent.impl.Promise$DefaultPromise.tryAwait(Promise.scala:206)
at
scala.concurrent.impl.Promise$DefaultPromise.ready(Promise.scala:222)
at
scala.concurrent.impl.Promise$DefaultPromise.result(Promise.scala:227)
at
org.apache.spark.util.ThreadUtils$.awaitResult(ThreadUtils.scala:220)
at org.apache.spark.util.ThreadUtils$.parmap(ThreadUtils.scala:317)
at
org.apache.spark.sql.execution.command.AlterTableRecoverPartitionsCommand.scanPartitions(ddl.scala:690)
at
org.apache.spark.sql.execution.command.AlterTableRecoverPartitionsCommand.run(ddl.scala:626)
at
org.apache.spark.sql.execution.command.ExecutedCommandExec.sideEffectResult$lzycompute(commands.scala:70)
- locked <0x0000000793b04e88> (a
org.apache.spark.sql.execution.command.ExecutedCommandExec)
at
org.apache.spark.sql.execution.command.ExecutedCommandExec.sideEffectResult(commands.scala:68)
at
org.apache.spark.sql.execution.command.ExecutedCommandExec.executeCollect(commands.scala:79)
...
```
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