Github user pwendell commented on a diff in the pull request:
https://github.com/apache/spark/pull/3389#discussion_r20683755
--- Diff:
streaming/src/main/scala/org/apache/spark/streaming/dstream/FileInputDStream.scala
---
@@ -155,83 +186,81 @@ class FileInputDStream[K: ClassTag, V: ClassTag, F <:
NewInputFormat[K,V] : Clas
private def readObject(ois: ObjectInputStream): Unit =
Utils.tryOrIOException {
logDebug(this.getClass().getSimpleName + ".readObject used")
ois.defaultReadObject()
+ allFoundFiles = new mutable.HashSet[String]()
generatedRDDs = new HashMap[Time, RDD[(K,V)]] ()
- files = new HashMap[Time, Array[String]]
- fileModTimes = new TimeStampedHashMap[String, Long](true)
+ timeToSelectedFileInfo = new HashMap[Time, SelectedFileInfo]
+ fileToModTimes = new TimeStampedHashMap[String,
Long](updateTimeStampOnGet = true)
}
/**
- * A custom version of the DStreamCheckpointData that stores names of
- * Hadoop files as checkpoint data.
+ * A custom version of the DStreamCheckpointData that stores the
information about the
+ * files selected in every batch. This is necessary so that the files
selected for the past
+ * batches (that have already been defined) can be recovered correctly
upon driver failure and
+ * the input data of the batches are exactly the same.
*/
private[streaming]
class FileInputDStreamCheckpointData extends DStreamCheckpointData(this)
{
- def hadoopFiles = data.asInstanceOf[HashMap[Time, Array[String]]]
+ def checkpointedFileInfo = data.asInstanceOf[HashMap[Time,
SelectedFileInfo]]
override def update(time: Time) {
- hadoopFiles.clear()
- hadoopFiles ++= files
+ checkpointedFileInfo.clear()
+ checkpointedFileInfo ++= timeToSelectedFileInfo
}
override def cleanup(time: Time) { }
override def restore() {
- hadoopFiles.toSeq.sortBy(_._1)(Time.ordering).foreach {
+ checkpointedFileInfo.toSeq.sortBy(_._1)(Time.ordering).foreach {
case (t, f) => {
// Restore the metadata in both files and generatedRDDs
- logInfo("Restoring files for time " + t + " - " +
- f.mkString("[", ", ", "]") )
- files += ((t, f))
- generatedRDDs += ((t, filesToRDD(f)))
+ logInfo(s"Restoring files for time $t - ${f.files.mkString(",
")}")
+ timeToSelectedFileInfo += ((t, f))
+ allFoundFiles ++= f.files
+ generatedRDDs += ((t, filesToRDD(f.files)))
}
}
}
override def toString() = {
- "[\n" + hadoopFiles.size + " file sets\n" +
- hadoopFiles.map(p => (p._1, p._2.mkString(", "))).mkString("\n") +
"\n]"
+ "[\n" + checkpointedFileInfo.size + " file sets\n" +
+ checkpointedFileInfo.map(p => (p._1, p._2.files.mkString(",
"))).mkString("\n") + "\n]"
}
}
/**
- * Custom PathFilter class to find new files that
- * ... have modification time more than ignore time
- * ... have not been seen in the last interval
- * ... have modification time less than maxModTime
+ * Custom PathFilter class to find new files that have modification time
within the
+ * remember window (that is mod time > ignore threshold) and have not
been selected in that
+ * window.
*/
- private[streaming]
- class CustomPathFilter(maxModTime: Long) extends PathFilter {
+ private class CustomPathFilter(modTimeIgnoreThreshold: Long) extends
PathFilter {
--- End diff --
The does not convey much other than that it is a subclass of `PathFilter`.
For instance I didn't realize off the bat that this also excluded files in
`allFoundFiles` (when I was reading the `findNewFiles` function), I assumed
from the constructor that it just filtered files older than that time.
Could this be named something like `ExcludeVisitedFilePathFilter`. Also,
could it take `allFoundFiles` and `fileModTimes` as constructor arguments? This
would localize the state used a bit more, right now it refers to these fields
of the outer class directly and from the call site it's not really clear what
logic it does.
---
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