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https://issues.apache.org/jira/browse/HDFS-14134?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16828886#comment-16828886
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Yuxuan Wang commented on HDFS-14134:
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Hello, anyone is working on this? I find a bug in
{{org.apache.hadoop.hdfs.server.namenode.ha.RequestHedgingProxyProvider}} .
Just like [~lukmajercak] said:
{quote}Also note that previously, if a hedging request got FAILOVER_RETRY and
some request got SocketExc on nonidempotent operation (e.g. FAIL), the client
would still pick FAILOVER_RETRY over FAIL, so i think we are fixing an issue
here as well.
{quote}
But more than this, standby namenode will always throw back StandbyException
which can cause {{FAILOVER_AND_RETRY}} action. It will cover all actions have
lower order than {{FAILOVER_AND_RETRY}}, such as {{RETRY}} in
[^HDFS-14134.007.patch].
I mean, the correct order should be {{Ordering: FAILOVER_AND_RETRY < RETRY <
FAIL}}, right ?
> Idempotent operations throwing RemoteException should not be retried by the
> client
> ----------------------------------------------------------------------------------
>
> Key: HDFS-14134
> URL: https://issues.apache.org/jira/browse/HDFS-14134
> Project: Hadoop HDFS
> Issue Type: Bug
> Components: hdfs, hdfs-client, ipc
> Reporter: Lukas Majercak
> Assignee: Lukas Majercak
> Priority: Critical
> Attachments: HDFS-14134.001.patch, HDFS-14134.002.patch,
> HDFS-14134.003.patch, HDFS-14134.004.patch, HDFS-14134.005.patch,
> HDFS-14134.006.patch, HDFS-14134.007.patch,
> HDFS-14134_retrypolicy_change_proposal.pdf,
> HDFS-14134_retrypolicy_change_proposal_1.pdf
>
>
> Currently, some operations that throw IOException on the NameNode are
> evaluated by RetryPolicy as FAILOVER_AND_RETRY, but they should just fail
> fast.
> For example, when calling getXAttr("user.some_attr", file") where the file
> does not have the attribute, NN throws an IOException with message "could not
> find attr". The current client retry policy determines the action for that to
> be FAILOVER_AND_RETRY. The client then fails over and retries until it
> reaches the maximum number of retries. Supposedly, the client should be able
> to tell that this exception is normal and fail fast.
> Moreover, even if the action was FAIL, the RetryInvocationHandler looks at
> all the retry actions from all requests, and FAILOVER_AND_RETRY takes
> precedence over FAIL action.
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