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ASF GitHub Bot commented on HDFS-17030: --------------------------------------- xinglin commented on code in PR #5700: URL: https://github.com/apache/hadoop/pull/5700#discussion_r1212421364 ########## hadoop-hdfs-project/hadoop-hdfs-client/src/main/java/org/apache/hadoop/hdfs/server/namenode/ha/ObserverReadProxyProvider.java: ########## @@ -155,12 +173,22 @@ */ private long observerProbeRetryPeriodMs; + /** + * Timeout in seconds when we try to get the HA state of an namenode. + */ + @VisibleForTesting + private long namenodeHAStateProbeTimeoutSec; + /** * The previous time where zero observer were found. If there was observer, * or it is initialization, this is set to 0. */ private long lastObserverProbeTime; + private final ExecutorService nnProbingThreadPool = + new ThreadPoolExecutor(1, 4, 60000L, TimeUnit.MILLISECONDS, Review Comment: replaced 60000L/MS with 1L/S. Hopefully, it is more intuitive. > Limit wait time for getHAServiceState in ObserverReaderProxy > ------------------------------------------------------------ > > Key: HDFS-17030 > URL: https://issues.apache.org/jira/browse/HDFS-17030 > Project: Hadoop HDFS > Issue Type: Improvement > Components: hdfs > Affects Versions: 3.4.0 > Reporter: Xing Lin > Assignee: Xing Lin > Priority: Minor > Labels: pull-request-available > > When namenode HA is enabled and a standby NN is not responsible, we have > observed it would take a long time to serve a request, even though we have a > healthy observer or active NN. > Basically, when a standby is down, the RPC client would (re)try to create > socket connection to that standby for _ipc.client.connect.timeout_ _* > ipc.client.connect.max.retries.on.timeouts_ before giving up. When we take a > heap dump at a standby, the NN still accepts the socket connection but it > won't send responses to these RPC requests and we would timeout after > _ipc.client.rpc-timeout.ms._ This adds a significantly latency. For clusters > at Linkedin, we set _ipc.client.rpc-timeout.ms_ to 120 seconds and thus a > request takes more than 2 mins to complete when we take a heap dump at a > standby. This has been causing user job failures. > We could set _ipc.client.rpc-timeout.ms to_ a smaller value when sending > getHAServiceState requests in ObserverReaderProxy (for user rpc requests, we > still use the original value from the config). However, that would double the > socket connection between clients and the NN (which is a deal-breaker). > The proposal is to add a timeout on getHAServiceState() calls in > ObserverReaderProxy and we will only wait for the timeout for an NN to > respond its HA state. Once we pass that timeout, we will move on to probe the > next NN. > -- This message was sent by Atlassian Jira (v8.20.10#820010) --------------------------------------------------------------------- To unsubscribe, e-mail: hdfs-issues-unsubscr...@hadoop.apache.org For additional commands, e-mail: hdfs-issues-h...@hadoop.apache.org