Improve task commit resilience everywhere
and add an option to reduce delete IO requests on
job cleanup (relevant for ABFS and HDFS).
Task Commit Resilience
----------------------
Task manifest saving is re-attempted on failure; the number of
attempts made is configurable with the option:
mapreduce.manifest.committer.manifest.save.attempts
* The default is 5.
* The minimum is 1; asking for less is ignored.
* A retry policy adds 500ms of sleep per attempt.
* Move from classic rename() to commitFile() to rename the file,
after calling getFileStatus() to get its length and possibly etag.
This becomes a rename() on gcs/hdfs anyway, but on abfs it does reach
the ResilientCommitByRename callbacks in abfs, which report on
the outcome to the caller...which is then logged at WARN.
* New statistic task_stage_save_summary_file to distinguish from
other saving operations (job success/report file).
This is only saved to the manifest on task commit retries, and
provides statistics on all previous unsuccessful attempts to save
the manifests
+ test changes to match the codepath changes, including improvements
in fault injection.
Directory size for deletion
---------------------------
New option
mapreduce.manifest.committer.cleanup.parallel.delete.base.first
This attempts an initial attempt at deleting the base dir, only falling
back to parallel deletes if there's a timeout.
This option is disabled by default; Consider enabling it for abfs to
reduce IO load. Consult the documentation for more details.
Success file printing
---------------------
The command to print a JSON _SUCCESS file from this committer and
any S3A committer is now something which can be invoked from
the mapred command:
mapred successfile <path to file>
Contributed by Steve Loughran
c9270600b7