Andrew Or created SPARK-3015:
--------------------------------
Summary: Removing broadcast in quick successions causes Akka
timeout
Key: SPARK-3015
URL: https://issues.apache.org/jira/browse/SPARK-3015
Project: Spark
Issue Type: Bug
Components: Spark Core
Affects Versions: 1.0.2
Environment: Standalone EC2 Spark shell
Reporter: Andrew Or
Priority: Blocker
Fix For: 1.1.0
This issue is originally reported in SPARK-2916 in the context of MLLib, but we
were able to reproduce it using a simple Spark shell command:
{code}
(1 to 10000).foreach { i => sc.parallelize(1 to 1000, 48).sum }
{code}
We still do not have a full understanding of the issue, but we have gleaned the
following information so far. When the driver runs a GC, it attempts to clean
up all the broadcast blocks that go out of scope at once. This causes the
driver to send out many blocking RemoveBroadcast messages to the executors,
which in turn send out blocking UpdateBlockInfo messages back to the driver.
Both of these calls block until they receive the expected responses. We suspect
that the high frequency at which we send these blocking messages is the cause
of either dropped messages or internal deadlock somewhere.
Unfortunately, it is highly difficult to reproduce depending on the
environment. We have been able to reproduce it on a 6-node cluster in
us-west-2, but not in us-west-1, for instance.
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