[GitHub] [flink] wsry commented on a change in pull request #18474: [FLINK-25786][network] Adjust the generation of subpartition data storage order for sort-shuffle from random shuffle to random shift

[GitBox]

wsry commented on a change in pull request #18474:
URL: https://github.com/apache/flink/pull/18474#discussion_r792449522



##########
File path: 
flink-runtime/src/main/java/org/apache/flink/runtime/io/network/partition/SortMergeResultPartition.java
##########
@@ -492,10 +490,13 @@ public int getNumberOfQueuedBuffers(int 
targetSubpartition) {
     }
 
     private int[] getRandomSubpartitionOrder(int numSubpartitions) {
-        List<Integer> list =
-                IntStream.range(0, 
numSubpartitions).boxed().collect(Collectors.toList());
-        Collections.shuffle(list);
-        return list.stream().mapToInt(Integer::intValue).toArray();
+        int[] order = new int[numSubpartitions];
+        Random random = new Random();
+        int shift = random.nextInt(numSubpartitions);

Review comment:
       Yes, it is expected. The motivation is for better sequential disk IO 
when there is no enough resources to run the downstream consumer tasks in 
parallel.




-- 
This is an automated message from the Apache Git Service.
To respond to the message, please log on to GitHub and use the
URL above to go to the specific comment.

To unsubscribe, e-mail: issues-unsubscr...@flink.apache.org

For queries about this service, please contact Infrastructure at:
us...@infra.apache.org