GitHub user aarondav opened a pull request:
https://github.com/apache/spark/pull/1321
[RFC] Disable local execution of Spark jobs by default
Currently, local execution of Spark jobs is only used by take(), and it can
be problematic as it can load a significant amount of data onto the driver. The
worst case scenarios occur if the RDD is cached (guaranteed to load whole
partition), has very large elements, or the partition is just large and we
apply a filter with high selectivity or computational overhead.
Additionally, jobs that run locally in this manner do not show up in the
web UI, and are thus harder to track or understand what is occurring.
This PR adds a flag to disable local execution, which is turned OFF by
default, with the intention of perhaps eventually removing this functionality
altogether. Removing it now is a tougher proposition since it is part of the
public runJob API. An alternative solution would be to limit the flag to
take()/first() to avoid impacting any external users of this API, but such
usage (or, at least, reliance upon the feature) is hopefully minimal.
You can merge this pull request into a Git repository by running:
$ git pull https://github.com/aarondav/spark allowlocal
Alternatively you can review and apply these changes as the patch at:
https://github.com/apache/spark/pull/1321.patch
To close this pull request, make a commit to your master/trunk branch
with (at least) the following in the commit message:
This closes #1321
----
commit 164b08a67ff05ce422cb2ec382c5b08469bb1e4e
Author: Aaron Davidson <aa...@databricks.com>
Date: 2014-07-07T20:52:12Z
[RFC] Disable local execution of Spark jobs by default
Currently, local execution of Spark jobs is only used by take(), and it can
be problematic as it can load a significant amount of data onto the driver.
The worst case scenarios occur if the RDD is cached (guaranteed to load
whole
partition), has very large elements, or the partition is just large and we
apply a filter with high selectivity or computational overhead.
Additionally, jobs that run locally in this manner do not show up in the
web UI,
and are thus harder to track or understand what is occurring.
This PR adds a flag to disable local execution, which is turned OFF by
default, with
the intention of perhaps eventually removing this functionality altogether.
Removing it
now is a tougher proposition since it is part of the public runJob API. An
alternative
solution would be to limit the flag to take()/first() to avoid impacting
any external
users of this API, but such usage (or at least, reliance upon the feature)
is hopefully
minimal.
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