scala – Spark：OutOfMemory尽管MEMORY_AND_DISK_SER

val data = SparkStartup.sqlContext.read.parquet(...)
data.setName(...).persist(StorageLevel.MEMORY_AND_DISK_SER).collect()
map += data

镶木地板文件总共约11克.我配置我的应用程序：

val sparkConfig = new SparkConf().setAppName(...).setMaster("local[128]")
sparkConfig.set("spark.serializer","org.apache.spark.serializer.KryoSerializer")
sparkConfig.set("spark.kryoserializer.buffer.max","512m");
sparkConfig.set("spark.kryoserializer.buffer","256");
sparkConfig.set("spark.driver.maxResultSize","0");
sparkConfig.set("spark.driver.memory","9g");

我认为通过使用MEMORY_AND_DISK_SER,如果使用太多内存,Spark会溢出到磁盘.但是,我得到`java.lang.OutOfMemoryError：Java堆空间错误

at java.util.Arrays.copyOf(Arrays.java:3230)
at java.io.ByteArrayOutputStream.grow(ByteArrayOutputStream.java:113)
at java.io.ByteArrayOutputStream.ensureCapacity(ByteArrayOutputStream.java:93)
at java.io.ByteArrayOutputStream.write(ByteArrayOutputStream.java:140)
at java.io.BufferedOutputStream.flushBuffer(BufferedOutputStream.java:82)
at java.io.BufferedOutputStream.write(BufferedOutputStream.java:126)
at com.esotericsoftware.kryo.io.Output.flush(Output.java:155)
at com.esotericsoftware.kryo.io.Output.require(Output.java:135)
at com.esotericsoftware.kryo.io.Output.writeAscii_slow(Output.java:446)
at com.esotericsoftware.kryo.io.Output.writeString(Output.java:306)
at com.esotericsoftware.kryo.util.DefaultClassResolver.writeName(DefaultClassResolver.java:105)
at com.esotericsoftware.kryo.util.DefaultClassResolver.writeClass(DefaultClassResolver.java:81)
at com.esotericsoftware.kryo.Kryo.writeClass(Kryo.java:472)

为什么是这样？我用-Xmx9g -Dspark.executor.memory = 9g -Dspark.executor.cores = 3启动我的应用程序.对于在一切崩溃之前读取的文件,我可以在SparkUI中看到,当读取到内存时,镶木地板文件的大小是其大小的9倍.