hfutatzhanghb commented on code in PR #5597:
URL: https://github.com/apache/hadoop/pull/5597#discussion_r1205453041
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hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/datanode/DataNode.java:
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@@ -2630,6 +2632,31 @@ public int getActiveTransferThreadCount() {
@Override // DataNodeMXBean
public Map<String, Map<String, Long>> getDatanodeNetworkCounts() {
+ int maxDisplay =
getConf().getInt(DFSConfigKeys.DFS_DATANODE_NETWORKERRORS_DISPLAY_TOPCOUNT,
+ DFSConfigKeys.DFS_DATANODE_NETWORKERRORS_DISPLAY_TOPCOUNT_DEFAULT);
+ if (maxDisplay >= 0) {
+ ConcurrentMap<String, Map<String, Long>> map =
datanodeNetworkCounts.asMap();
+ Set<Map.Entry<String, Map<String, Long>>> entries = map.entrySet();
+ List<Map.Entry<String, Map<String, Long>>> list = new
ArrayList<>(entries);
+ Collections.sort(list, new Comparator<Entry<String, Map<String,
Long>>>() {
+ @Override
+ public int compare(Map.Entry<String, Map<String, Long>> o1,
+ Map.Entry<String, Map<String, Long>> o2) {
+ Map<String, Long> value1Map = o1.getValue();
+ Map<String, Long> value2Map = o2.getValue();
+ long compared = value2Map.getOrDefault(DataNode.NETWORK_ERRORS, 0L) -
+ value1Map.getOrDefault(DataNode.NETWORK_ERRORS, 0L);
+ return (int)compared;
+ }
+ });
+ Map<String, Map<String, Long>> resultMap = new ConcurrentHashMap<>();
+ maxDisplay = list.size() > maxDisplay ? maxDisplay : list.size();
+ for (int i = 0; i < maxDisplay; i++) {
+ resultMap.put(list.get(i).getKey(), list.get(i).getValue());
+ }
+ list.clear();
Review Comment:
Sir, it's better to clear the list here to prevent memory leak.
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