NickyYe commented on a change in pull request #2080:
URL: https://github.com/apache/hadoop/pull/2080#discussion_r444685702
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File path:
hadoop-hdfs-project/hadoop-hdfs-rbf/src/main/java/org/apache/hadoop/hdfs/server/federation/router/RouterRpcServer.java
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@@ -1748,4 +1828,58 @@ public void refreshSuperUserGroupsConfiguration() throws
IOException {
public String[] getGroupsForUser(String user) throws IOException {
return routerProto.getGroupsForUser(user);
}
-}
\ No newline at end of file
+
+ /**
+ * Deals with loading datanode report into the cache and refresh.
+ */
+ private class DatanodeReportCacheLoader
+ extends CacheLoader<DatanodeReportType, DatanodeInfo[]> {
+
+ private ListeningExecutorService executorService;
+
+ DatanodeReportCacheLoader() {
+ ThreadFactory threadFactory = new ThreadFactoryBuilder()
+ .setNameFormat("DatanodeReport-Cache-Reload")
+ .setDaemon(true)
+ .build();
+
+ // Only use 1 thread to refresh cache.
+ // With coreThreadCount == maxThreadCount we effectively
+ // create a fixed size thread pool. As allowCoreThreadTimeOut
+ // has been set, all threads will die after 60 seconds of non use.
+ ThreadPoolExecutor parentExecutor = new ThreadPoolExecutor(
+ 1,
+ 1,
+ 60,
+ TimeUnit.SECONDS,
+ new LinkedBlockingQueue<Runnable>(),
+ threadFactory);
+ parentExecutor.allowCoreThreadTimeOut(true);
+ executorService = MoreExecutors.listeningDecorator(parentExecutor);
+ }
+
+ @Override
+ public DatanodeInfo[] load(DatanodeReportType type) throws Exception {
+ return getCachedDatanodeReportImpl(type);
+ }
+
+ /**
+ * Override the reload method to provide an asynchronous implementation,
+ * so that the query will not be slowed down by the cache refresh. It
+ * will return the old cache value and schedule a background refresh.
+ */
+ @Override
+ public ListenableFuture<DatanodeInfo[]> reload(
+ final DatanodeReportType type, DatanodeInfo[] oldValue)
+ throws Exception {
+ ListenableFuture<DatanodeInfo[]> listenableFuture =
Review comment:
Thank you for the comments. I've addressed all of them.
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