[SPARK-19599][SS] Clean up HDFSMetadataLog

## What changes were proposed in this pull request?

SPARK-19464 removed support for Hadoop 2.5 and earlier, so we can do some cleanup for HDFSMetadataLog.

This PR includes the following changes:
- ~~Remove the workaround codes for HADOOP-10622.~~ Unfortunately, there is another issue [HADOOP-14084](https://issues.apache.org/jira/browse/HADOOP-14084) that prevents us from removing the workaround codes.
- Remove unnecessary `writer: (T, OutputStream) => Unit` and just call `serialize` directly.
- Remove catching FileNotFoundException.

## How was this patch tested?

Jenkins

Author: Shixiong Zhu <shixiong@databricks.com>

Closes #16932 from zsxwing/metadata-cleanup.

2 files changed, 19 insertions, 24 deletions

diff --git a/sql/core/src/main/scala/org/apache/spark/sql/execution/streaming/HDFSMetadataLog.scala b/sql/core/src/main/scala/org/apache/spark/sql/execution/streaming/HDFSMetadataLog.scala
index bfdc2cb0ac..3155ce04a1 100644
--- a/sql/core/src/main/scala/org/apache/spark/sql/execution/streaming/HDFSMetadataLog.scala
+++ b/sql/core/src/main/scala/org/apache/spark/sql/execution/streaming/HDFSMetadataLog.scala
@@ -114,15 +114,18 @@ class HDFSMetadataLog[T <: AnyRef : ClassTag](sparkSession: SparkSession, path:
           case ut: UninterruptibleThread =>
             // When using a local file system, "writeBatch" must be called on a
             // [[org.apache.spark.util.UninterruptibleThread]] so that interrupts can be disabled
-            // while writing the batch file. This is because there is a potential dead-lock in
-            // Hadoop "Shell.runCommand" before 2.5.0 (HADOOP-10622). If the thread running
-            // "Shell.runCommand" is interrupted, then the thread can get deadlocked. In our case,
-            // `writeBatch` creates a file using HDFS API and will call "Shell.runCommand" to set
-            // the file permission if using the local file system, and can get deadlocked if the
-            // stream execution thread is stopped by interrupt. Hence, we make sure that
-            // "writeBatch" is called on [[UninterruptibleThread]] which allows us to disable
-            // interrupts here. Also see SPARK-14131.
-            ut.runUninterruptibly { writeBatch(batchId, metadata, serialize) }
+            // while writing the batch file.
+            //
+            // This is because Hadoop "Shell.runCommand" swallows InterruptException (HADOOP-14084).
+            // If the user tries to stop a query, and the thread running "Shell.runCommand" is
+            // interrupted, then InterruptException will be dropped and the query will be still
+            // running. (Note: `writeBatch` creates a file using HDFS APIs and will call
+            // "Shell.runCommand" to set the file permission if using the local file system)
+            //
+            // Hence, we make sure that "writeBatch" is called on [[UninterruptibleThread]] which
+            // allows us to disable interrupts here, in order to propagate the interrupt state
+            // correctly. Also see SPARK-19599.
+            ut.runUninterruptibly { writeBatch(batchId, metadata) }
           case _ =>
             throw new IllegalStateException(
               "HDFSMetadataLog.add() on a local file system must be executed on " +
@@ -132,20 +135,19 @@ class HDFSMetadataLog[T <: AnyRef : ClassTag](sparkSession: SparkSession, path:
         // For a distributed file system, such as HDFS or S3, if the network is broken, write
         // operations may just hang until timeout. We should enable interrupts to allow stopping
         // the query fast.
-        writeBatch(batchId, metadata, serialize)
+        writeBatch(batchId, metadata)
       }
       true
     }
   }
 
-  def writeTempBatch(metadata: T, writer: (T, OutputStream) => Unit = serialize): Option[Path] = {
-    var nextId = 0
+  def writeTempBatch(metadata: T): Option[Path] = {
     while (true) {
       val tempPath = new Path(metadataPath, s".${UUID.randomUUID.toString}.tmp")
       try {
         val output = fileManager.create(tempPath)
         try {
-          writer(metadata, output)
+          serialize(metadata, output)
           return Some(tempPath)
         } finally {
           IOUtils.closeQuietly(output)
@@ -164,7 +166,6 @@ class HDFSMetadataLog[T <: AnyRef : ClassTag](sparkSession: SparkSession, path:
           // big problem because it requires the attacker must have the permission to write the
           // metadata path. In addition, the old Streaming also have this issue, people can create
           // malicious checkpoint files to crash a Streaming application too.
-          nextId += 1
       }
     }
     None
@@ -176,8 +177,8 @@ class HDFSMetadataLog[T <: AnyRef : ClassTag](sparkSession: SparkSession, path:
    * There may be multiple [[HDFSMetadataLog]] using the same metadata path. Although it is not a
    * valid behavior, we still need to prevent it from destroying the files.
    */
-  private def writeBatch(batchId: Long, metadata: T, writer: (T, OutputStream) => Unit): Unit = {
-    val tempPath = writeTempBatch(metadata, writer).getOrElse(
+  private def writeBatch(batchId: Long, metadata: T): Unit = {
+    val tempPath = writeTempBatch(metadata).getOrElse(
       throw new IllegalStateException(s"Unable to create temp batch file $batchId"))
     try {
       // Try to commit the batch
@@ -195,12 +196,6 @@ class HDFSMetadataLog[T <: AnyRef : ClassTag](sparkSession: SparkSession, path:
         // So throw an exception to tell the user this is not a valid behavior.
         throw new ConcurrentModificationException(
           s"Multiple HDFSMetadataLog are using $path", e)
-      case e: FileNotFoundException =>
-        // Sometimes, "create" will succeed when multiple writers are calling it at the same
-        // time. However, only one writer can call "rename" successfully, others will get
-        // FileNotFoundException because the first writer has removed it.
-        throw new ConcurrentModificationException(
-          s"Multiple HDFSMetadataLog are using $path", e)
     } finally {
       fileManager.delete(tempPath)
     }
diff --git a/sql/core/src/main/scala/org/apache/spark/sql/execution/streaming/StreamExecution.scala b/sql/core/src/main/scala/org/apache/spark/sql/execution/streaming/StreamExecution.scala
index 3149ef04f7..239d49b08a 100644
--- a/sql/core/src/main/scala/org/apache/spark/sql/execution/streaming/StreamExecution.scala
+++ b/sql/core/src/main/scala/org/apache/spark/sql/execution/streaming/StreamExecution.scala
@@ -179,8 +179,8 @@ class StreamExecution(
 
   /**
    * The thread that runs the micro-batches of this stream. Note that this thread must be
-   * [[org.apache.spark.util.UninterruptibleThread]] to avoid potential deadlocks in using
-   * [[HDFSMetadataLog]]. See SPARK-14131 for more details.
+   * [[org.apache.spark.util.UninterruptibleThread]] to avoid swallowing `InterruptException` when
+   * using [[HDFSMetadataLog]]. See SPARK-19599 for more details.
    */
   val microBatchThread =
     new StreamExecutionThread(s"stream execution thread for $prettyIdString") {