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https://issues.apache.org/jira/browse/HDFS-9103?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14990154#comment-14990154
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Haohui Mai commented on HDFS-9103:
----------------------------------
bq. The set should be sitting in cache anyway if it's reasonably sized and
accessed recently but if it turns cache misses are leading to pipeline stalls
I'll certainly swap it out for a vector.
Every node in the set requires a separate heap allocation. They might scatter
around the address space. {{vector}} is on the heap as well but it guarantees
continuous amount of memory. Some implementation of {{string}} has inlined
buffer which has much better cache locality results.
bq. As far as node exclusion policy goes is it reasonable to assume that
kResourceUnavailable will always refer to something local like too many open
sockets? I wouldn't want to prevent exclusion if it's the DN sending that.
Checking with the code {{kResourceUnavailable}} is only for the NN cannot find
any DNs to serve this data. I don't think we'll need to handle this case
when excluding the DNs.
> Retry reads on DN failure
> -------------------------
>
> Key: HDFS-9103
> URL: https://issues.apache.org/jira/browse/HDFS-9103
> Project: Hadoop HDFS
> Issue Type: Sub-task
> Components: hdfs-client
> Reporter: Bob Hansen
> Assignee: James Clampffer
> Fix For: HDFS-8707
>
> Attachments: HDFS-9103.1.patch, HDFS-9103.2.patch,
> HDFS-9103.HDFS-8707.006.patch, HDFS-9103.HDFS-8707.3.patch,
> HDFS-9103.HDFS-8707.4.patch, HDFS-9103.HDFS-8707.5.patch
>
>
> When AsyncPreadSome fails, add the failed DataNode to the excluded list and
> try again.
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