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https://issues.apache.org/jira/browse/HDFS-17030?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17728168#comment-17728168
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ASF GitHub Bot commented on HDFS-17030:
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xinglin commented on code in PR #5700:
URL: https://github.com/apache/hadoop/pull/5700#discussion_r1212422395
##########
hadoop-hdfs-project/hadoop-hdfs-client/src/main/java/org/apache/hadoop/hdfs/server/namenode/ha/ObserverReadProxyProvider.java:
##########
@@ -88,6 +96,16 @@
/** Observer probe retry period default to 10 min. */
static final long OBSERVER_PROBE_RETRY_PERIOD_DEFAULT = 60 * 10 * 1000;
+ /** Timeout to cancel the ha-state probe rpc request for an namenode. */
+ static final String NAMENODE_HA_STATE_PROBE_TIMEOUT =
+ "dfs.client.namenode.ha-state.probe.timeout";
+ /**
+ * Namenode ha-state probe timeout default to 25 sec.
+ * ipc.client.connect.timeout defaults to be 20 seconds. So, in 25 seconds,
+ * we can try twice to connect to an NN.
+ */
+ static final long NAMENODE_HA_STATE_PROBE_TIMEOUT_DEFAULT = 25;
Review Comment:
not sure how to address this. I don't think that is required neither. In
many places, we use an integer/long value together with TimeUnit, to refer a
duration. It is the same in this case. autoMsyncPeriodMs in this class is also
a long.
`private final long autoMsyncPeriodMs;`
> 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.
>
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