First, there is currently no public documentation for this setting. So it's hard
to even know that it could be a problem if your application starts failing with
weird shuffle errors.
Second, the javadoc attached to the code was incorrect; the default value just uses
the default value from the JRE, which is 50, instead of having an unbounded queue
as the comment implies.
So use a default that is a "rounded" version of the JRE default, and provide
documentation explaining that this value may need to be adjusted. Also added
a log message that was very helpful in debugging an issue caused by this
problem.
Closes#24732 from vanzin/SPARK-27868.
Authored-by: Marcelo Vanzin <vanzin@cloudera.com>
Signed-off-by: Dongjoon Hyun <dhyun@apple.com>
09ed64d795