Github user sryza commented on a diff in the pull request:
https://github.com/apache/spark/pull/2087#discussion_r18833578
--- Diff: core/src/main/scala/org/apache/spark/deploy/SparkHadoopUtil.scala
---
@@ -121,6 +125,31 @@ class SparkHadoopUtil extends Logging {
UserGroupInformation.loginUserFromKeytab(principalName, keytabFilename)
}
+ /**
+ * Returns a function that can be called to find the number of Hadoop
FileSystem bytes read by
+ * this thread so far. Reflection is required because thread-level
FileSystem statistics are only
+ * available as of Hadoop 2.5 (see HADOOP-10688). Returns None if the
required method can't be
+ * found.
+ */
+ def getInputBytesReadCallback(path: Path, conf: Configuration):
Option[() => Long] = {
+ val qualifiedPath = path.getFileSystem(conf).makeQualified(path)
+ val scheme = qualifiedPath.toUri().getScheme()
+ val stats =
FileSystem.getAllStatistics().filter(_.getScheme().equals(scheme))
+ try {
+ val threadStats = stats.map(Utils.invoke(classOf[Statistics], _,
"getThreadStatistics"))
+ val statisticsDataClass =
+
Class.forName("org.apache.hadoop.fs.FileSystem$Statistics$StatisticsData")
+ val getBytesReadMethod =
statisticsDataClass.getDeclaredMethod("getBytesRead")
+ val f = () =>
threadStats.map(getBytesReadMethod.invoke(_).asInstanceOf[Long]).sum
+ val start = f()
+ Some(() => f() - start)
--- End diff --
`getBytesRead` will give you the bytes since the thread was created. As
executors can put multiple tasks on the same thread, calling it without a delta
could include bytes read from a previous task. I'll comment / restructure this
to make it a little more clear.
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