Github user mridulm commented on a diff in the pull request:
https://github.com/apache/spark/pull/1609#discussion_r15565486
--- Diff:
core/src/main/scala/org/apache/spark/storage/BlockObjectWriter.scala ---
@@ -107,68 +109,296 @@ private[spark] class DiskBlockObjectWriter(
private var fos: FileOutputStream = null
private var ts: TimeTrackingOutputStream = null
private var objOut: SerializationStream = null
+
+ // Did we create this file or was it already present : used in revert to
decide
+ // if we should delete this file or not. Also used to detect if file was
deleted
+ // between creation of BOW and its actual init
+ private val initiallyExists = file.exists() && file.isFile
private val initialPosition = file.length()
private var lastValidPosition = initialPosition
+
private var initialized = false
+ // closed explicitly ?
+ private var closed = false
+ // Attempt to cleanly close ? (could also be closed via revert)
+ // Note, a cleanly closed file could be subsequently reverted
+ private var cleanCloseAttempted = false
+ // Was the file actually opened atleast once.
+ // Note: initialized/streams change state with close/revert.
+ private var wasOpenedOnce = false
private var _timeWriting = 0L
- override def open(): BlockObjectWriter = {
- fos = new FileOutputStream(file, true)
- ts = new TimeTrackingOutputStream(fos)
- channel = fos.getChannel()
+ // Due to some directory creation race issues in spark, it has been
observed that
+ // sometimes file creation happens 'before' the actual directory has
been created
+ // So we attempt to retry atleast once with a mkdirs in case directory
was missing.
+ private def init() {
+ init(canRetry = true)
+ }
+
+ private def init(canRetry: Boolean) {
+
+ if (closed) throw new IOException("Already closed")
+
+ assert (! initialized)
+ assert (! wasOpenedOnce)
+ var exists = false
+ try {
+ exists = file.exists()
+ if (! exists && initiallyExists && 0 != initialPosition && !
Utils.inShutdown) {
+ // Was deleted by cleanup thread ?
+ throw new IOException("file " + file + " cleaned up ? exists = " +
exists +
+ ", initiallyExists = " + initiallyExists + ", initialPosition =
" + initialPosition)
+ }
+ fos = new FileOutputStream(file, true)
+ } catch {
+ case fEx: FileNotFoundException =>
+ // There seems to be some race in directory creation.
+ // Attempts to fix it dont seem to have worked : working around
the problem for now.
+ logDebug("Unable to open " + file + ", canRetry = " + canRetry +
", exists = " + exists +
+ ", initialPosition = " + initialPosition + ", in shutdown = " +
Utils.inShutdown(), fEx)
+ if (canRetry && ! Utils.inShutdown()) {
+ // try creating the parent directory if that is the issue.
+ // Since there can be race with others, dont bother checking for
+ // success/failure - the call to init() will resolve if fos can
be created.
+ file.getParentFile.mkdirs()
+ // Note, if directory did not exist, then file does not either -
and so
+ // initialPosition would be zero in either case.
+ init(canRetry = false)
+ return
+ } else throw fEx
+ }
+
+ try {
+ // This is to workaround case where creation of object and actual
init
+ // (which can happen much later) happens after a delay and the
cleanup thread
+ // cleaned up the file.
+ channel = fos.getChannel
+ val fosPos = channel.position()
+ if (initialPosition != fosPos) {
+ throw new IOException("file cleaned up ? " + file.exists() +
+ ", initialpos = " + initialPosition +
+ "current len = " + fosPos + ", in shutdown ? " +
Utils.inShutdown)
+ }
+
+ ts = new TimeTrackingOutputStream(fos)
+ val bos = new BufferedOutputStream(ts, bufferSize)
+ bs = compressStream(bos)
+ objOut = serializer.newInstance().serializeStream(bs)
+ initialized = true
+ wasOpenedOnce = true;
+ } finally {
+ if (! initialized) {
+ // failed, cleanup state.
+ val tfos = fos
+ updateCloseState()
+ tfos.close()
+ }
+ }
+ }
+
+ private def open(): BlockObjectWriter = {
+ init()
lastValidPosition = initialPosition
- bs = compressStream(new BufferedOutputStream(ts, bufferSize))
- objOut = serializer.newInstance().serializeStream(bs)
- initialized = true
this
}
- override def close() {
- if (initialized) {
- if (syncWrites) {
- // Force outstanding writes to disk and track how long it takes
- objOut.flush()
+ private def updateCloseState() {
+
+ if (ts ne null) _timeWriting += ts.timeWriting
--- End diff --
The only reason to use eq/ne was to avoid the call to equals/canEquals/etc.
Since spark ships with assertions turned on, this ends up being expensive
since some of the codepaths are very frequent : and all changes in the 2G fix
branch uses eq/ne.
Not sure how relevant it is to this patch though ... I can revert to ==/!=
if it is a problem !
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