[
https://issues.apache.org/jira/browse/HDFS-4942?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13695837#comment-13695837
]
Suresh Srinivas edited comment on HDFS-4942 at 6/30/13 7:43 PM:
----------------------------------------------------------------
This issue was discussed in HadoopSummit 2013, HDFS Design Lounge. Folks
participated in the discussion agreed about the need for retry cache. Here are
some high level decisions:
# Retry cache will be added to the namenode for non-idempotent operations. An
entry in retry cache will be retained for a configurable period of time. It
will track non-idempotent requests when they successfully complete.
# To identify a request uniquely, currently RPC call ID is not sufficient.
Additional identifiers will be added to RPC to uniquely identify requests
coming from the same client, two clients on the same machine and two clients on
different machines.
I will post a design by early next week.
was (Author: sureshms):
This issue was discussed in HadoopSummit 2013, HDFS Design Lounge. Folks
participated in the discussion agreed about the need for retry cache. Here are
some high level decisions:
# Retry cache will be added to the namenode for idempotent operations. An entry
in retry cache will be retained for configurable period of time. It will track
non-idempotent requests when they successfully complete.
# To identify a request uniquely, currently RPC call ID is not sufficient.
Additional identifiers will be added to RPC to uniquely identify requests
coming from the same client, two clients on the same machine and two clients on
different machines.
I will post a design by early next week.
> Add retry cache support in Namenode
> -----------------------------------
>
> Key: HDFS-4942
> URL: https://issues.apache.org/jira/browse/HDFS-4942
> Project: Hadoop HDFS
> Issue Type: Improvement
> Components: ha, namenode
> Reporter: Suresh Srinivas
> Assignee: Suresh Srinivas
>
> In current HA mechanism with FailoverProxyProvider and non HA setups with
> RetryProxy retry a request from the RPC layer. If the retried request has
> already been processed at the namenode, the subsequent attempts fail for
> non-idempotent operations such as create, append, delete, rename etc. This
> will cause application failures during HA failover, network issues etc.
> This jira proposes adding retry cache at the namenode to handle these
> failures. More details in the comments.
--
This message is automatically generated by JIRA.
If you think it was sent incorrectly, please contact your JIRA administrators
For more information on JIRA, see: http://www.atlassian.com/software/jira
