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https://issues.apache.org/jira/browse/HDFS-13578?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16479379#comment-16479379
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Chao Sun commented on HDFS-13578:
---------------------------------
[~xkrogen]: good point. I think we should recommend people to disable the
access time if they opt for observer reads (which is what we do internally), or
still direct {{getBlockLocations}} to active if access time is turned on. I've
seen RPC time suffered when access time is on and {{getBlockLocations}} goes to
observer. This may need more discussion.
[~elgoiri]: we can use this annotation to check whether the current RPC method
is readonly or not, by following:
{code:java}
private boolean isRead(Method method) {
return method.isAnnotationPresent(ReadOnly.class);
}
{code}
> Add ReadOnly annotation to methods in ClientProtocol
> ----------------------------------------------------
>
> Key: HDFS-13578
> URL: https://issues.apache.org/jira/browse/HDFS-13578
> Project: Hadoop HDFS
> Issue Type: Sub-task
> Reporter: Chao Sun
> Assignee: Chao Sun
> Priority: Major
> Attachments: HDFS-13578-HDFS-12943.000.patch
>
>
> For those read-only methods in {{ClientProtocol}}, we may want to use a
> {{@ReadOnly}} annotation to mark them, and then check in the proxy provider
> for observer.
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