[SPARK-32701][CORE][DOCS] mapreduce.fileoutputcommitter.algorithm.version default value #29541
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The current documentation states that the default value of spark.hadoop.mapreduce.fileoutputcommitter.algorithm.version is 1 which is not entirely true since this configuration isn't set anywhere in Spark but rather inherited from the Hadoop FileOutputCommitter class.
What changes were proposed in this pull request?
I'm submitting this change, to clarify that the default value will entirely depend on the Hadoop version of the runtime environment.
Why are the changes needed?
An application would end up using algorithm version 1 on certain environments but without any changes the same exact application will use version 2 on environments running Hadoop 3.0 and later. This can have pretty bad consequences in certain scenarios, for example, two tasks can partially overwrite their output if speculation is enabled. Also, please refer to the following JIRA:
https://issues.apache.org/jira/browse/MAPREDUCE-7282
Does this PR introduce any user-facing change?
Yes. Configuration page content was modified where previously we explicitly highlighted that the default version for the FileOutputCommitter algorithm was v1, this now has changed to "Dependent on environment" with additional information in the description column to elaborate.
How was this patch tested?
Checked changes locally in browser