[GitHub] art4ul opened a new pull request #6608: [FLINK-10203]Support truncate method for old Hadoop versions in HadoopRecoverableFsDataOutputStream

[GitBox <gi...@apache.org>]

art4ul opened a new pull request #6608: [FLINK-10203]Support truncate method for old Hadoop versions in HadoopRecoverableFsDataOutputStream
URL: https://github.com/apache/flink/pull/6608
 
 
   ## What is the purpose of the change
   
   New StreamingFileSink ( introduced in 1.6 Flink version ) use HadoopRecoverableFsDataOutputStream wrapper to write data in HDFS.
   
   HadoopRecoverableFsDataOutputStream is an wrapper on FSDataOutputStream to have an ability to restore from certain point of file after failure and continue write data. To achive this recover functionality the HadoopRecoverableFsDataOutputStream use "truncate" method which was introduced only in Hadoop 2.7 .
   
   Unfortently there are a few official Hadoop distibutives which latast version still use Hadoop 2.6 (This distibutives: Cloudera, Pivotal HD ). As the result Flink can't work with this distibutives.
   
   Flink declares that supported Hadoop from version 2.4.0 upwards (https://ci.apache.org/projects/flink/flink-docs-release-1.6/start/building.html#hadoop-versions)
   
   I guess we should emulate the functionality of "truncate" method for older Hadoop versions.
   
   This is possible fix . I would like to start discussion here. 
   The fix of this issue is vital for us as Hadoop 2.6 users.
   
   ## Brief change log
   
     - Add new abstraction TruncateManager
     - Add Implementation for old Hadoop version ( LegacyTruncateManager)
     - Add Implementation for Hadoop 2.7 and upwards
   
   
   ## Verifying this change
   
   This change contains only possible solution but currently without any test coverage.
   Tests will be added after final consensus about implementation .
   
   ## Does this pull request potentially affect one of the following parts:
   
     - Dependencies (does it add or upgrade a dependency): (no)
     - The public API, i.e., is any changed class annotated with `@Public(Evolving)`: (no)
     - The serializers: ( no)
     - The runtime per-record code paths (performance sensitive): (don't know)
     - Anything that affects deployment or recovery: JobManager (and its components), Checkpointing, Yarn/Mesos, ZooKeeper: (yes)
     - The S3 file system connector: ( no)
   
   ## Documentation
   
     - Does this pull request introduce a new feature? (no, but I think it should be documented)
     - If yes, how is the feature documented? (not documented yet)
   

----------------------------------------------------------------
This is an automated message from the Apache Git Service.
To respond to the message, please log on GitHub and use the
URL above to go to the specific comment.
 
For queries about this service, please contact Infrastructure at:
users@infra.apache.org


With regards,
Apache Git Services