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https://issues.apache.org/jira/browse/HADOOP-17028?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17370329#comment-17370329
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Konstantin Shvachko commented on HADOOP-17028:
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Steve, this looks like incompatible change as it replaced the parameter to a
different class:
{code}
public static <T> CompletableFuture<T> eval(
- FunctionsRaisingIOE.CallableRaisingIOE<T> callable) {
+ CallableRaisingIOE<T> callable) {
CompletableFuture<T> result = new CompletableFuture<>();
{code}
Also introduction of dead code should have been avoided. Looking at the
history, you introduced
{{org.apache.hadoop.fs.impl.FunctionsRaisingIOE.FunctionRaisingIOE}} as a part
of HADOOP-15183. But it wasn't used anywhere. Then HADOOP-17450 deprecated it.
One good thing about it that you can remove the deprecated classes as they have
never been used.
Supporting dead code is just a waste of energy it also makes back porting
really hard. You don't seem to care about older versions, but many people do.
> ViewFS should initialize target filesystems lazily
> --------------------------------------------------
>
> Key: HADOOP-17028
> URL: https://issues.apache.org/jira/browse/HADOOP-17028
> Project: Hadoop Common
> Issue Type: Bug
> Components: client-mounts, fs, viewfs
> Affects Versions: 3.2.1
> Reporter: Uma Maheswara Rao G
> Assignee: Abhishek Das
> Priority: Major
> Labels: pull-request-available
> Time Spent: 5h 40m
> Remaining Estimate: 0h
>
> Currently viewFS initialize all configured target filesystems when
> viewfs#init itself.
> Some target file system initialization involve creating heavy objects and
> proxy connections. Ex: DistributedFileSystem#initialize will create DFSClient
> object which will create proxy connections to NN etc.
> For example: if ViewFS configured with 10 target fs with hdfs uri and 2
> targets with s3a.
> If one of the client only work with s3a target, But ViewFS will initialize
> all targets irrespective of what clients interested to work with. That means,
> here client will create 10 DFS initializations and 2 s3a initializations. Its
> unnecessary to have DFS initialization here. So, it will be a good idea to
> initialize the target fs only when first time usage call come to particular
> target fs scheme.
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