Github user jinxing64 commented on a diff in the pull request:
https://github.com/apache/spark/pull/18031#discussion_r117610285
--- Diff: core/src/main/scala/org/apache/spark/scheduler/MapStatus.scala ---
@@ -193,8 +219,27 @@ private[spark] object HighlyCompressedMapStatus {
} else {
0
}
+ val threshold1 = Option(SparkEnv.get)
+ .map(_.conf.get(config.SHUFFLE_ACCURATE_BLOCK_THRESHOLD))
+ .getOrElse(config.SHUFFLE_ACCURATE_BLOCK_THRESHOLD.defaultValue.get)
+ val threshold2 = avgSize * Option(SparkEnv.get)
+
.map(_.conf.get(config.SHUFFLE_ACCURATE_BLOCK_THRESHOLD_BY_TIMES_AVERAGE))
+
.getOrElse(config.SHUFFLE_ACCURATE_BLOCK_THRESHOLD_BY_TIMES_AVERAGE.defaultValue.get)
+ val threshold = math.max(threshold1, threshold2)
+ val hugeBlockSizesArray = ArrayBuffer[Tuple2[Int, Byte]]()
+ if (numNonEmptyBlocks > 0) {
+ i = 0
+ while (i < totalNumBlocks) {
+ if (uncompressedSizes(i) > threshold) {
+ hugeBlockSizesArray += Tuple2(i,
MapStatus.compressSize(uncompressedSizes(i)))
+
+ }
+ i += 1
+ }
+ }
emptyBlocks.trim()
emptyBlocks.runOptimize()
- new HighlyCompressedMapStatus(loc, numNonEmptyBlocks, emptyBlocks,
avgSize)
+ new HighlyCompressedMapStatus(loc, numNonEmptyBlocks, emptyBlocks,
avgSize,
--- End diff --
@viirya Thanks a lot for taking time looking into this pr :)
> remove the huge blocks from the numerator in that calculation so that you
more accurately size the smaller blocks
Yes, I think this is really good idea to have accurate size for smaller
blocks. But I'm proposing two configs(`spark.shuffle.accurateBlockThreshold`
and `spark.shuffle.accurateBlockThresholdByTimesAverage` ) in current change, I
have to compute the average twice: 1) the average calculated including huge
blocks, thus I can filter out the huge blocks 2) the average calculated without
huge blocks, thus I can have accurate size for the smaller blocks. A little bit
complicated, right? How about remove the
`spark.shuffle.accurateBlockThresholdByTimesAverage` ? Thus we can simplify the
logic. @cloud-fan Any ideas about this?
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