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https://issues.apache.org/jira/browse/HDFS-9103?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14997662#comment-14997662
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Haohui Mai commented on HDFS-9103:
----------------------------------
Just take a quick skim.
{code}
template <class MutableBufferSequence, class Handler>
void AsyncPreadSome(size_t offset, const MutableBufferSequence &buffers,
- const std::set<std::string> &excluded_datanodes,
- const Handler &handler);
+ const Handler &handler,
+ std::shared_ptr<NodeExclusionRule>
optional_rule_override = nullptr);
151 std::shared_ptr<NodeExclusionRule> rule = optional_exclude_rule !=
nullptr ?
152 optional_exclude_rule :
bad_node_tracker_;
{code}
Let's remove the default argument and make it explicit for the caller.
{code}
+ /* prune orphaned DNs from list periodically */
+ if(remove_counter_++ % 1024 == 0 && remove_counter_ != 0) {
+ RemoveAllExpired();
+ remove_counter_ = 0;
+ }
{code}
There is no need to do this. You can sort the lists by expiration time so that
the fast path will always return in the first iteration.
> 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-8707.007.patch,
> HDFS-9103.HDFS-8707.008.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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