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https://issues.apache.org/jira/browse/HDFS-6634?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14111634#comment-14111634
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Colin Patrick McCabe commented on HDFS-6634:
--------------------------------------------
The new design doc looks really good.
{code}
[email protected]
[email protected]
+public class MissingEventsException extends Exception {
{code}
Since this is part of the public API, we should have a friendly toString method
that prints something like "inotify was unable to locate some events. We
expected txid X, but were only able to read up to txid Y"
Re: INVALID_TXID. I think that we don't need to add this to the proto file as
I suggested earlier. The only way to add it would be as an enum value, which
seems like kind of a hack. So it's fine as-is.
Re: the QuorumJournalManager changes: [~tlipcon], [~james.thomas],
[~andrew.wang] and I talked offline about this. The existing logic in QJM to
prevent reading uncommitted edits should suffice, so we shouldn't need to add
the ability to fetch the writer epoch via an RPC. There should never be
divergent QJM edit logs... as Todd pointed out, each QJM edit log should be
up-to-date, or a prefix of an up-to-date log. We should do something to avoid
rescanning those "in-progress" edit logs to find the final txid over and over
on the JournalNodes, though.
Overall, great work, James... I think this is almost ready to go.
> inotify in HDFS
> ---------------
>
> Key: HDFS-6634
> URL: https://issues.apache.org/jira/browse/HDFS-6634
> Project: Hadoop HDFS
> Issue Type: New Feature
> Components: hdfs-client, namenode, qjm
> Reporter: James Thomas
> Assignee: James Thomas
> Attachments: HDFS-6634.2.patch, HDFS-6634.3.patch, HDFS-6634.4.patch,
> HDFS-6634.5.patch, HDFS-6634.6.patch, HDFS-6634.patch, inotify-design.2.pdf,
> inotify-design.3.pdf, inotify-design.4.pdf, inotify-design.pdf,
> inotify-intro.2.pdf, inotify-intro.pdf
>
>
> Design a mechanism for applications like search engines to access the HDFS
> edit stream.
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