Returns true if an in-progress job commit can be retried. If the MR AM is
re-run then it will check this value to determine if it can retry an
in-progress commit that was started by a previous version.
Note that in rare scenarios, the previous AM version might still be running
at that time, due to system anomalies. Hence if this method returns true
then the retry commit operation should be able to run concurrently with
the previous operation.
If repeatable job commit is supported, job restart can tolerate previous
AM failures during job commit.
By default, it is not supported. Extended classes (like:
FileOutputCommitter) should explicitly override it if provide support.