[
https://issues.apache.org/jira/browse/HDFS-8088?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14487757#comment-14487757
]
Colin Patrick McCabe commented on HDFS-8088:
--------------------------------------------
Thanks for looking at this.
bq. Colin, thanks for working on this, I have not gone through HDFS-8069, does
it really degrade the performance of DFSInputStream a lot? If so, I think this
is a block issue and let's make it in ASAP.
It doesn't degrade the performance at all if tracing is turned off.
bq. \[The change to hedgedReadId\] is not necessary.
True, but I think it's more intuitive to start the count at 1 than 0. Just for
some background, {{hedgedReadId}} is something I introduced, and which is only
used for tracing.
> Reduce the number of HTrace spans generated by HDFS reads
> ---------------------------------------------------------
>
> Key: HDFS-8088
> URL: https://issues.apache.org/jira/browse/HDFS-8088
> Project: Hadoop HDFS
> Issue Type: Improvement
> Reporter: Colin Patrick McCabe
> Assignee: Colin Patrick McCabe
> Attachments: HDFS-8088.001.patch
>
>
> HDFS generates too many trace spans on read right now. Every call to read()
> we make generates its own span, which is not very practical for things like
> HBase or Accumulo that do many such reads as part of a single operation.
> Instead of tracing every call to read(), we should only trace the cases where
> we refill the buffer inside a BlockReader.
--
This message was sent by Atlassian JIRA
(v6.3.4#6332)
