Steve Armstrong created HDFS-7800: ------------------------------------- Summary: Improve documentation for FileSystem.concat() Key: HDFS-7800 URL: https://issues.apache.org/jira/browse/HDFS-7800 Project: Hadoop HDFS Issue Type: Task Affects Versions: 2.6.0, 2.2.0 Reporter: Steve Armstrong
This is a documentation request. [FileSystem.concat()|https://hadoop.apache.org/docs/current/api/org/apache/hadoop/fs/FileSystem.html] says it will "Concat existing files together". It seems to be a Namenode-only operation though, mapping the data blocks into a single file. This means: # The destination must exist # The destination must be non-empty # The destination must have it's last block exactly full # All but the last of the source files must have their last block full # All the source file will be deleted by this operation HDFS-6641 brought up some of these limitations, but was closed as not a problem. I think the javadoc should be improved so it's clear this function was never intended to work the same as a general purpose file concatenation. -- This message was sent by Atlassian JIRA (v6.3.4#6332)