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https://issues.apache.org/jira/browse/YARN-1307?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13804382#comment-13804382
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Bikas Saha commented on YARN-1307:
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Not quite sure what you mean by encoding. There is nothing to encode. The data
needs to be serialized and stored in both cases. In the batch case, the data
needs to be serialized with a delimiter to differentiate between records.
We dont need to read and then write the znode. We can always just write the
znode since we already have all the data. There is no token in the store that
is not already present in the RM's memory since the RM also needs to know about
these tokens. So the state store can maintain the all the tokens batches with
sequence number range in each batch. Since tokens will be created in
monotonically increasing sequence numbers, maintaining and looking up the index
is simple.
To be clear, we are speaking only about storing RMDelegationTokens. We can take
the same approach for AppAttempts within an App.
> Rethink znode structure for RM HA
> ---------------------------------
>
> Key: YARN-1307
> URL: https://issues.apache.org/jira/browse/YARN-1307
> Project: Hadoop YARN
> Issue Type: Sub-task
> Components: resourcemanager
> Reporter: Tsuyoshi OZAWA
> Assignee: Tsuyoshi OZAWA
> Attachments: YARN-1307.1.patch, YARN-1307.2.patch
>
>
> Rethink for znode structure for RM HA is proposed in some JIRAs(YARN-659,
> YARN-1222). The motivation of this JIRA is quoted from Bikas' comment in
> YARN-1222:
> {quote}
> We should move to creating a node hierarchy for apps such that all znodes for
> an app are stored under an app znode instead of the app root znode. This will
> help in removeApplication and also in scaling better on ZK. The earlier code
> was written this way to ensure create/delete happens under a root znode for
> fencing. But given that we have moved to multi-operations globally, this isnt
> required anymore.
> {quote}
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