Github user ericl commented on a diff in the pull request:
https://github.com/apache/spark/pull/13382#discussion_r71262947
--- Diff:
core/src/main/scala/org/apache/spark/storage/DiskBlockObjectWriter.scala ---
@@ -46,102 +46,145 @@ private[spark] class DiskBlockObjectWriter(
extends OutputStream
with Logging {
+ /**
+ * Guards against close calls, e.g. from a wrapping stream.
+ * Call manualClose to close the stream that was extended by this trait.
+ */
+ private trait ManualCloseOutputStream extends OutputStream {
+ abstract override def close(): Unit = {
+ flush()
+ }
+
+ def manualClose(): Unit = {
+ super.close()
+ }
+ }
+
/** The file channel, used for repositioning / truncating the file. */
private var channel: FileChannel = null
+ private var mcs: ManualCloseOutputStream = null
private var bs: OutputStream = null
private var fos: FileOutputStream = null
private var ts: TimeTrackingOutputStream = null
private var objOut: SerializationStream = null
private var initialized = false
+ private var streamOpen = false
private var hasBeenClosed = false
- private var commitAndCloseHasBeenCalled = false
/**
* Cursors used to represent positions in the file.
*
- * xxxxxxxx|--------|--- |
- * ^ ^ ^
- * | | finalPosition
- * | reportedPosition
- * initialPosition
+ * xxxxxxxx|--------|---|
+ * ^ ^
+ * | committedPosition
+ * reportedPosition
*
- * initialPosition: Offset in the file where we start writing. Immutable.
* reportedPosition: Position at the time of the last update to the
write metrics.
- * finalPosition: Offset where we stopped writing. Set on
closeAndCommit() then never changed.
+ * committedPosition: Offset after last committed write.
* -----: Current writes to the underlying file.
* xxxxx: Existing contents of the file.
*/
- private val initialPosition = file.length()
- private var finalPosition: Long = -1
- private var reportedPosition = initialPosition
+ private var committedPosition = file.length()
+ private var reportedPosition = committedPosition
/**
* Keep track of number of records written and also use this to
periodically
* output bytes written since the latter is expensive to do for each
record.
*/
private var numRecordsWritten = 0
+ private def initialize(): Unit = {
+ fos = new FileOutputStream(file, true)
+ channel = fos.getChannel()
+ ts = new TimeTrackingOutputStream(writeMetrics, fos)
+ class ManualCloseBufferedOutputStream
+ extends BufferedOutputStream(ts, bufferSize) with
ManualCloseOutputStream
+ mcs = new ManualCloseBufferedOutputStream
+ }
+
def open(): DiskBlockObjectWriter = {
if (hasBeenClosed) {
throw new IllegalStateException("Writer already closed. Cannot be
reopened.")
}
- fos = new FileOutputStream(file, true)
- ts = new TimeTrackingOutputStream(writeMetrics, fos)
- channel = fos.getChannel()
- bs = compressStream(new BufferedOutputStream(ts, bufferSize))
+ if (!initialized) {
+ initialize()
+ initialized = true
+ }
+ bs = compressStream(mcs)
objOut = serializerInstance.serializeStream(bs)
- initialized = true
+ streamOpen = true
this
}
- override def close() {
+ /**
+ * Close and cleanup all resources.
+ * Should call after committing or reverting partial writes.
+ */
+ private def closeResources(): Unit = {
if (initialized) {
- Utils.tryWithSafeFinally {
- if (syncWrites) {
- // Force outstanding writes to disk and track how long it takes
- objOut.flush()
- val start = System.nanoTime()
- fos.getFD.sync()
- writeMetrics.incWriteTime(System.nanoTime() - start)
- }
- } {
- objOut.close()
- }
-
+ mcs.manualClose()
channel = null
+ mcs = null
bs = null
fos = null
ts = null
objOut = null
initialized = false
+ streamOpen = false
hasBeenClosed = true
}
}
- def isOpen: Boolean = objOut != null
+ /**
+ * Commits any remaining partial writes and closes resources.
+ */
+ override def close() {
+ if (initialized) {
+ Utils.tryWithSafeFinally {
+ commit()
+ } {
+ closeResources()
+ }
+ }
+ }
/**
* Flush the partial writes and commit them as a single atomic block.
+ * A commit may write additional bytes to frame the atomic block.
+ *
+ * @return file segment with previous offset and length committed on
this call.
*/
- def commitAndClose(): Unit = {
- if (initialized) {
+ def commit(): FileSegment = {
--- End diff --
nit: commitAndGet()?
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