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https://issues.apache.org/jira/browse/SPARK-20760?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16042177#comment-16042177
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Jose Soltren commented on SPARK-20760:
--------------------------------------
Hi Binzi:
1. If this is so then there is some error in my understanding.
2. I don't have a good answer here yet, sorry.
3. Though these RDD operations appear serially in your test program, they are
all asynchronous behind the scenes. In particular, unpersisting RDDs really
amounts to the driver sending the executors a bunch of messages to do
unpersisting. Since they are asynchronous, decoupled operations, it is possible
for one to be faster than another.
I'm not entirely sure precisely what changed since Spark 1.6 here. My
investigation was focused on where all the memory was going, not in digesting
all the changes across a major version of Spark. Cheers.
> Memory Leak of RDD blocks
> --------------------------
>
> Key: SPARK-20760
> URL: https://issues.apache.org/jira/browse/SPARK-20760
> Project: Spark
> Issue Type: Bug
> Components: Block Manager
> Affects Versions: 2.1.0
> Environment: Spark 2.1.0
> Reporter: Binzi Cao
> Attachments: RDD blocks in spark 2.1.1.png, RDD Blocks .png, Storage
> in spark 2.1.1.png
>
>
> Memory leak for RDD blocks for a long time running rdd process.
> We have a long term running application, which is doing computations of
> RDDs. and we found the RDD blocks are keep increasing in the spark ui page.
> The rdd blocks and memory usage do not mach the cached rdds and memory. It
> looks like spark keeps old rdd in memory and never released it or never got a
> chance to release it. The job will eventually die of out of memory.
> In addition, I'm not seeing this issue in spark 1.6. We are seeing the same
> issue in Yarn Cluster mode both in kafka streaming and batch applications.
> The issue in streaming is similar, however, it seems the rdd blocks grows a
> bit slower than batch jobs.
> The below is the sample code and it is reproducible by justing running it in
> local mode.
> Scala file:
> {code}
> import scala.concurrent.duration.Duration
> import scala.util.{Try, Failure, Success}
> import org.apache.spark.SparkConf
> import org.apache.spark.SparkContext
> import org.apache.spark.rdd.RDD
> import scala.concurrent._
> import ExecutionContext.Implicits.global
> case class Person(id: String, name: String)
> object RDDApp {
> def run(sc: SparkContext) = {
> while (true) {
> val r = scala.util.Random
> val data = (1 to r.nextInt(100)).toList.map { a =>
> Person(a.toString, a.toString)
> }
> val rdd = sc.parallelize(data)
> rdd.cache
> println("running")
> val a = (1 to 100).toList.map { x =>
> Future(rdd.filter(_.id == x.toString).collect)
> }
> a.foreach { f =>
> println(Await.ready(f, Duration.Inf).value.get)
> }
> rdd.unpersist()
> }
> }
> def main(args: Array[String]): Unit = {
> val conf = new SparkConf().setAppName("test")
> val sc = new SparkContext(conf)
> run(sc)
> }
> }
> {code}
> build sbt file:
> {code}
> name := "RDDTest"
> version := "0.1.1"
> scalaVersion := "2.11.5"
> libraryDependencies ++= Seq (
> "org.scalaz" %% "scalaz-core" % "7.2.0",
> "org.scalaz" %% "scalaz-concurrent" % "7.2.0",
> "org.apache.spark" % "spark-core_2.11" % "2.1.0" % "provided",
> "org.apache.spark" % "spark-hive_2.11" % "2.1.0" % "provided"
> )
> addCompilerPlugin("org.spire-math" %% "kind-projector" % "0.7.1")
> mainClass in assembly := Some("RDDApp")
> test in assembly := {}
> {code}
> To reproduce it:
> Just
> {code}
> spark-2.1.0-bin-hadoop2.7/bin/spark-submit --driver-memory 4G \
> --executor-memory 4G \
> --executor-cores 1 \
> --num-executors 1 \
> --class "RDDApp" --master local[4] RDDTest-assembly-0.1.1.jar
> {code}
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