[
https://issues.apache.org/jira/browse/HDFS-8272?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14520406#comment-14520406
]
Zhe Zhang commented on HDFS-8272:
---------------------------------
Thanks Jing for the update. I agree about removing {{seekToBlockSource}} at
this stage.
bq. With decoding functionality we do not need to spend more time trying our
luck on the same DN.
It's an interesting thought. Actually, it seems striped files should have a
longer window to retry the same DN than replicated files; since it's more
expensive to decode than fetching a replica from another DN.
bq. Currently calling seekToBlockSource will cause all the current block
readers to be closed (since blockSeekTo will call closeCurrentBlockReaders). To
fix this we need to add extra complexity so as to make sure only one block
reader is retried.
bq. How about removing it by now and we can add it back if necessary in the
future?
I agree. It's not straightforward to only retry one block reader. We should do
it as a follow-on task under HDFS-8031.
I will post my full review soon.
> Erasure Coding: simplify the retry logic in DFSStripedInputStream (stateful
> read)
> ---------------------------------------------------------------------------------
>
> Key: HDFS-8272
> URL: https://issues.apache.org/jira/browse/HDFS-8272
> Project: Hadoop HDFS
> Issue Type: Sub-task
> Reporter: Jing Zhao
> Assignee: Jing Zhao
> Attachments: HDFS-8272.002.patch, h8272-HDFS-7285.000.patch,
> h8272-HDFS-7285.001.patch
>
>
> Currently in DFSStripedInputStream the retry logic is still the same with
> DFSInputStream. More specifically, every failed read will try to search for
> another source node. And an exception is thrown when no new source node can
> be identified. This logic is not appropriate for EC inputstream and can be
> simplified.
--
This message was sent by Atlassian JIRA
(v6.3.4#6332)
