You are viewing a plain text version of this content. The canonical link for it is here.
Posted to dev@crunch.apache.org by "Jeffrey Quinn (JIRA)" <ji...@apache.org> on 2015/12/05 02:21:11 UTC
[jira] [Created] (CRUNCH-580) FileTargetImpl#handleOutputs
Inefficiency on S3NativeFileSystem
Jeffrey Quinn created CRUNCH-580:
------------------------------------
Summary: FileTargetImpl#handleOutputs Inefficiency on S3NativeFileSystem
Key: CRUNCH-580
URL: https://issues.apache.org/jira/browse/CRUNCH-580
Project: Crunch
Issue Type: Bug
Components: Core, IO
Affects Versions: 0.13.0
Environment: Amazon Elastic Map Reduce
Reporter: Jeffrey Quinn
Assignee: Josh Wills
We have run in to a pretty frustrating inefficiency inside of org.apache.crunch.io.impl.FileTargetImpl#handleOutputs.
This method loops over all of the partial output files and moves them to their ultimate destination directories, calling org.apache.hadoop.fs.FileSystem#rename(org.apache.hadoop.fs.Path, org.apache.hadoop.fs.Path) on each partial output in a loop.
This is no problem when the org.apache.hadoop.fs.FileSystem in question is HDFS where #rename is a cheap operation, but when an implementation such as S3NativeFileSystem is used it is extremely inefficient, as each iteration through the loop makes a single blocking S3 API call, and this loop can be extremely long when there are many thousands of partial output files.
--
This message was sent by Atlassian JIRA
(v6.3.4#6332)