I'm running a massive file sifting by timestamp DataSteam job from s3. The basic job is: FileMonitor -> ContinuousFileReader -> MultipleFileOutputSink
The MultipleFileOutputSink sifts data based on timestamp to date-hour directories It's a lot of data, so I'm using high parallelism, but I want to maintain reasonable output file size, so if I key post-ContinuousFileReader by 5-minute timestamp keys I get the desired result of large files at the cost of a network shuffle. But since I also have timestamps on the input files I figured I could push back the keyed stream to FileMonitor -> ContinuousFileReader and save the network shuffle. I tested this and confirmed that it sort of worked and ContinuousFileReaders are receiving properly partitioned input, but output post reader is now rebalanced and sinks produce lots of tiny files. The code is below. Am I missing something? val source = env .addSource(fileMonitor) .name(s"Bucketed Log Source File Watcher: $path") .keyBy(new KeySelector[TimestampedFileInputSplit, Long]() { override def getKey(split: TimestampedFileInputSplit): Long = { val name = split.getPath.getName val r = """(\d+)\.log""".r r.findFirstMatchIn(name) match { case Some(m) ⇒ { val t = m.group(1).toLong t - (t % 300) } case _ ⇒ -1 } } }) .transform[String]("Bucketed Log Source File Reader", fileReader) .forward .assignTimestampsAndWatermarks(WatermarkExtractor[String]) .forward .addSink(SourceTrackingSink(Sift.outputBucket, BidDateFunc))