hi,
I am trying to write some unit test, following spark programming guide
<http://spark.apache.org/docs/latest/programming-guide.html#unit-testing>.
but I observed unit test runs very slow(the code is just a SparkPi), so I
turn log level to trace and look through the log output. and found
creation of SparkContext seems to take most time.
there are some action take a lot of time:
1, seems starting jetty
14:04:55.038 [ScalaTest-run-running-MySparkPiSpec] DEBUG
o.e.jetty.servlet.ServletHandler -
servletNameMap={org.apache.spark.ui.JettyUtils$$anon$1-672f11c2=org.apache.spark.ui.JettyUtils$$anon$1-672f11c2}
14:05:25.121 [ScalaTest-run-running-MySparkPiSpec] DEBUG
o.e.jetty.util.component.Container - Container
org.eclipse.jetty.server.Server@e3cee7b +
SelectChannelConnector@0.0.0.0:4040 as connector
2, I don't know what's this
14:05:25.202 [ScalaTest-run-running-MySparkPiSpec] DEBUG
org.apache.hadoop.security.Groups - Group mapping
impl=org.apache.hadoop.security.ShellBasedUnixGroupsMapping;
cacheTimeout=300000
14:05:54.594 [spark-akka.actor.default-dispatcher-4] TRACE
o.a.s.s.BlockManagerMasterActor - Checking for hosts with no recent heart
beats in BlockManagerMaster.
are there any way to make this faster for unit test?
I also notice in spark's unit test, that there exists a SharedSparkContext
<https://github.com/apache/spark/blob/master/core/src/test/scala/org/apache/spark/SharedSparkContext.scala>,
is this the suggested way to work around this problem? if so, I would
suggest to document this in programming guide.
