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https://issues.apache.org/jira/browse/HADOOP-16852?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=18044560#comment-18044560
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ASF GitHub Bot commented on HADOOP-16852:
-----------------------------------------
github-actions[bot] closed pull request #2147: HADOOP-16852: Report read-ahead
error back
URL: https://github.com/apache/hadoop/pull/2147
> ABFS: Send error back to client for Read Ahead request failure
> --------------------------------------------------------------
>
> Key: HADOOP-16852
> URL: https://issues.apache.org/jira/browse/HADOOP-16852
> Project: Hadoop Common
> Issue Type: Sub-task
> Components: fs/azure
> Affects Versions: 3.3.1
> Reporter: Sneha Vijayarajan
> Assignee: Sneha Vijayarajan
> Priority: Major
> Labels: pull-request-available
> Fix For: 3.3.1
>
> Time Spent: 1h 10m
> Remaining Estimate: 0h
>
> Issue seen by a customer:
> The failed requests we were seeing in the AbfsClient logging actually never
> made it out over the wire. We have found that there’s an issue with ADLS
> passthrough and the 8 read ahead threads that ADLSv2 spawns in
> ReadBufferManager.java. We depend on thread local storage in order to get the
> right JWT token and those threads do not have the right information in their
> thread local storage. Thus, when they pick up a task from the read ahead
> queue they fail by throwing an AzureCredentialNotFoundException exception in
> AbfsRestOperation.executeHttpOperation() where it calls
> client.getAccessToken(). This exception is silently swallowed by the read
> ahead threads in ReadBufferWorker.run(). As a result, every read ahead
> attempt results in a failed executeHttpOperation(), but still calls
> AbfsClientThrottlingIntercept.updateMetrics() and contributes to throttling
> (despite not making it out over the wire). After the read aheads fail, the
> main task thread performs the read with the right thread local storage
> information and succeeds, but first sleeps for up to 10 seconds due to the
> throttling.
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