Github user brkyvz commented on a diff in the pull request:
https://github.com/apache/spark/pull/15235#discussion_r80574449
--- Diff:
sql/core/src/main/scala/org/apache/spark/sql/execution/datasources/ListingFileCatalog.scala
---
@@ -82,73 +85,185 @@ class ListingFileCatalog(
* This is publicly visible for testing.
*/
def listLeafFiles(paths: Seq[Path]): mutable.LinkedHashSet[FileStatus] =
{
- if (paths.length >=
sparkSession.sessionState.conf.parallelPartitionDiscoveryThreshold) {
- HadoopFsRelation.listLeafFilesInParallel(paths, hadoopConf,
sparkSession)
- } else {
- // Right now, the number of paths is less than the value of
- // parallelPartitionDiscoveryThreshold. So, we will list file
statues at the driver.
- // If there is any child that has more files than the threshold, we
will use parallel
- // listing.
-
- // Dummy jobconf to get to the pathFilter defined in configuration
- val jobConf = new JobConf(hadoopConf, this.getClass)
- val pathFilter = FileInputFormat.getInputPathFilter(jobConf)
-
- val statuses: Seq[FileStatus] = paths.flatMap { path =>
- val fs = path.getFileSystem(hadoopConf)
- logTrace(s"Listing $path on driver")
-
- val childStatuses = {
- try {
- val stats = fs.listStatus(path)
- if (pathFilter != null) stats.filter(f =>
pathFilter.accept(f.getPath)) else stats
- } catch {
- case _: FileNotFoundException =>
- logWarning(s"The directory $path was not found. Was it
deleted very recently?")
- Array.empty[FileStatus]
- }
- }
+ val files =
+ if (paths.length >=
sparkSession.sessionState.conf.parallelPartitionDiscoveryThreshold) {
+ ListingFileCatalog.listLeafFilesInParallel(paths, hadoopConf,
sparkSession)
+ } else {
+ ListingFileCatalog.listLeafFilesInSerial(paths, hadoopConf)
+ }
+
+ mutable.LinkedHashSet(files: _*)
+ }
+
+ override def equals(other: Any): Boolean = other match {
+ case hdfs: ListingFileCatalog => paths.toSet == hdfs.paths.toSet
+ case _ => false
+ }
+
+ override def hashCode(): Int = paths.toSet.hashCode()
+}
+
+
+object ListingFileCatalog extends Logging {
+
+ // `FileStatus` is Writable but not serializable. What make it worse,
somehow it doesn't play
+ // well with `SerializableWritable`. So there seems to be no way to
serialize a `FileStatus`.
+ // Here we use `SerializableFileStatus` to extract key components of a
`FileStatus` to serialize
+ // it from executor side and reconstruct it on driver side.
+ private case class SerializableBlockLocation(
+ names: Array[String],
+ hosts: Array[String],
+ offset: Long,
+ length: Long)
+
+ private case class SerializableFileStatus(
+ path: String,
+ length: Long,
+ isDir: Boolean,
+ blockReplication: Short,
+ blockSize: Long,
+ modificationTime: Long,
+ accessTime: Long,
+ blockLocations: Array[SerializableBlockLocation])
+
+ /**
+ * List a collection of path recursively.
+ */
+ private def listLeafFilesInSerial(
+ paths: Seq[Path],
+ hadoopConf: Configuration): Seq[FileStatus] = {
+ // Dummy jobconf to get to the pathFilter defined in configuration
+ val jobConf = new JobConf(hadoopConf, this.getClass)
+ val filter = FileInputFormat.getInputPathFilter(jobConf)
+
+ paths.flatMap { path =>
+ logTrace(s"Listing $path")
+ val fs = path.getFileSystem(hadoopConf)
+
+ // [SPARK-17599] Prevent ListingFileCatalog from failing if path
doesn't exist
+ val status: Option[FileStatus] = try Option(fs.getFileStatus(path))
catch {
--- End diff --
I don't think you need this. You are increasing the number of `getStatus`
calls that we need to make. There is no guarantee that the folder will exist
once `listLeafFiles0` is called.
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