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https://issues.apache.org/jira/browse/HADOOP-19120?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17864291#comment-17864291
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ASF GitHub Bot commented on HADOOP-19120:
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steveloughran commented on PR #6633:
URL: https://github.com/apache/hadoop/pull/6633#issuecomment-2218245792
ok, let's ee what this test run says.
One thing I've just realised is that there is no public documentation for
this. Which it needs
proposed: somewhere you add a section on this in the public docs
* list the new options
* why httpclient is needed on the classpath
* show how to fall back to jvm
This can be done as a followup: what is key is "people shouldn't need to
read the source to see this stuff"
> [ABFS]: ApacheHttpClient adaptation as network library
> ------------------------------------------------------
>
> Key: HADOOP-19120
> URL: https://issues.apache.org/jira/browse/HADOOP-19120
> Project: Hadoop Common
> Issue Type: Sub-task
> Components: fs/azure
> Affects Versions: 3.5.0
> Reporter: Pranav Saxena
> Assignee: Pranav Saxena
> Priority: Major
> Labels: pull-request-available
> Fix For: 3.5.0, 3.4.1
>
>
> Apache HttpClient is more feature-rich and flexible and gives application
> more granular control over networking parameter.
> ABFS currently relies on the JDK-net library. This library is managed by
> OpenJDK and has no performance problem. However, it limits the application's
> control over networking, and there are very few APIs and hooks exposed that
> the application can use to get metrics, choose which and when a connection
> should be reused. ApacheHttpClient will give important hooks to fetch
> important metrics and control networking parameters.
> A custom implementation of connection-pool is used. The implementation is
> adapted from the JDK8 connection pooling. Reasons for doing it:
> 1. PoolingHttpClientConnectionManager heuristic caches all the reusable
> connections it has created. JDK's implementation only caches limited number
> of connections. The limit is given by JVM system property
> "http.maxConnections". If there is no system-property, it defaults to 5.
> Connection-establishment latency increased with all the connections were
> cached. Hence, adapting the pooling heuristic of JDK netlib,
> 2. In PoolingHttpClientConnectionManager, it expects the application to
> provide `setMaxPerRoute` and `setMaxTotal`, which the implementation uses as
> the total number of connections it can create. For application using ABFS, it
> is not feasible to provide a value in the initialisation of the
> connectionManager. JDK's implementation has no cap on the number of
> connections it can have opened on a moment. Hence, adapting the pooling
> heuristic of JDK netlib,
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