[
https://issues.apache.org/jira/browse/HDFS-1774?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13067180#comment-13067180
]
Uma Maheswara Rao G commented on HDFS-1774:
-------------------------------------------
Thanks a lot Eli, for taking a look on this patch.
Here since children is an array, i am just adding the elements into list and
converting it to array if it has elements.
old code will just loop two times and perform isDirectory checks twice.
> Small optimization in org.apache.hadoop.hdfs.server.datanode.FSDataset class.
> -----------------------------------------------------------------------------
>
> Key: HDFS-1774
> URL: https://issues.apache.org/jira/browse/HDFS-1774
> Project: Hadoop HDFS
> Issue Type: Improvement
> Components: data-node
> Reporter: Uma Maheswara Rao G
> Assignee: Uma Maheswara Rao G
> Fix For: 0.23.0
>
> Attachments: HDFS-1774-1.patch, HDFS-1774-1.patch, HDFS-1774.patch
>
>
> Inner class FSDir constructor is doing duplicate iterations over the listed
> files in the passed directory. We can optimize this to single loop and also
> we can avoid isDirectory check which will perform some native invocations.
> Consider a case: one directory has only one child directory and 10000
> files.
> 1) First loop will get the number of children directories.
> 2) if (numChildren > 0) , This condition will satisfy and again it will
> iterate 10001 times and also will check isDirectory.
--
This message is automatically generated by JIRA.
For more information on JIRA, see: http://www.atlassian.com/software/jira
