[
https://issues.apache.org/jira/browse/HDFS-8924?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14703916#comment-14703916
]
Colin Patrick McCabe commented on HDFS-8924:
--------------------------------------------
This patch adds a pluggable {{ReplicaAccessorBuilder}} class which can be used
to create {{ReplicaAccessor}} objects. Unlike {{BlockReader}},
{{ReplicaAccessor}} is a stable API which is decoupled from internal
implementation details and non-public classes. {{BlockReaderFactory}} will ask
all of the configured {{ReplicaAccessorBuilder}} objects to create a new
{{ReplicaAccessor}}. If none are configured, or none can create one, we use
the existing block reader code. Otherwise, we create an
{{ExternalBlockReader}} wrapping the {{ReplicaAccessor}}. I also added a
reserved {{DataTransferProtocol}} opcode (127) in {{Op.java}}. This will
ensure that anyone adding a custom opcode will not conflict with other new
opcodes added upstream.
> Add pluggable interface for reading replicas in DFSClient
> ---------------------------------------------------------
>
> Key: HDFS-8924
> URL: https://issues.apache.org/jira/browse/HDFS-8924
> Project: Hadoop HDFS
> Issue Type: Improvement
> Components: hdfs-client
> Affects Versions: 2.8.0
> Reporter: Colin Patrick McCabe
> Assignee: Colin Patrick McCabe
> Attachments: HDFS-8924.001.patch
>
>
> We should add a pluggable interface for reading replicas in the DFSClient.
> This could be used to implement short-circuit reads on systems without file
> descriptors, or for other optimizations.
--
This message was sent by Atlassian JIRA
(v6.3.4#6332)
