[错误]Caused by: org.apache.spark.memory.SparkOutOfMemoryError: Unable to acquire 65536 bytes of memory, got 0

今天，在运行Spark SQL代码的时候，遇到了以下错误：

Caused by: org.apache.spark.SparkException: Job aborted due to stage failure: Task 3 in stage 50.0 failed 4 times, most recent failure: Lost task 3.3 in stage 50.0 (TID 9204, bjhw-feed-shunyi2513.bjhw.baidu.com, executor 20): org.apache.spark.SparkException: Task failed while writing rows
    at org.apache.spark.internal.io.SparkHadoopWriter$.org$apache$spark$internal$io$SparkHadoopWriter$$executeTask(SparkHadoopWriter.scala:165)
    at org.apache.spark.internal.io.SparkHadoopWriter$$anonfun$3.apply(SparkHadoopWriter.scala:93)
    at org.apache.spark.internal.io.SparkHadoopWriter$$anonfun$3.apply(SparkHadoopWriter.scala:88)
    at org.apache.spark.scheduler.ResultTask.runTask(ResultTask.scala:87)
    at org.apache.spark.scheduler.Task.run(Task.scala:112)
    at org.apache.spark.executor.Executor$TaskRunner.run(Executor.scala:345)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
    at java.lang.Thread.run(Thread.java:748)
Caused by: org.apache.spark.memory.SparkOutOfMemoryError: Unable to acquire 65536 bytes of memory, got 0
    at org.apache.spark.memory.MemoryConsumer.throwOom(MemoryConsumer.java:157)
    at org.apache.spark.memory.MemoryConsumer.allocateArray(MemoryConsumer.java:98)
    at org.apache.spark.util.collection.unsafe.sort.UnsafeInMemorySorter.<init>(UnsafeInMemorySorter.java:128)
    at org.apache.spark.util.collection.unsafe.sort.UnsafeExternalSorter.<init>(UnsafeExternalSorter.java:161)
    at org.apache.spark.util.collection.unsafe.sort.UnsafeExternalSorter.create(UnsafeExternalSorter.java:128)
    at org.apache.spark.sql.execution.UnsafeExternalRowSorter.<init>(UnsafeExternalRowSorter.java:108)
    at org.apache.spark.sql.execution.UnsafeExternalRowSorter.create(UnsafeExternalRowSorter.java:93)
    at org.apache.spark.sql.execution.SortExec.createSorter(SortExec.scala:87)
    at org.apache.spark.sql.catalyst.expressions.GeneratedClass$GeneratedIteratorForCodegenStage22.init(Unknown Source)
    at org.apache.spark.sql.execution.WholeStageCodegenExec$$anonfun$10.apply(WholeStageCodegenExec.scala:611)
    at org.apache.spark.sql.execution.WholeStageCodegenExec$$anonfun$10.apply(WholeStageCodegenExec.scala:608)
    at org.apache.spark.rdd.RDD$$anonfun$mapPartitionsWithIndex$1$$anonfun$apply$26.apply(RDD.scala:847)
    at org.apache.spark.rdd.RDD$$anonfun$mapPartitionsWithIndex$1$$anonfun$apply$26.apply(RDD.scala:847)
    at org.apache.spark.rdd.MapPartitionsRDD.compute(MapPartitionsRDD.scala:38)
    at org.apache.spark.rdd.RDD.computeOrReadCheckpoint(RDD.scala:324)

Spark SQL关键代码如下：

spark.sql(
      s"""
         |select
         |$baseDay,
         |T1.type,
         |T1.app_id,
         |T1.name,
         |T1.level,
         |T1.business_line_id,
         |T1.status,
         |T1.quota,
         |T1.real_flow,
         |T1.real_show,
         |T1.article_num,
         |T1.baoliang_num,
         |T1.baoliang_finish_num,
         |T1.begin_time,
         |T1.end_time,
         |T2.fawen_num_bjh,
         |T3.fawen_num_tth,
         |T4.fenfa_num_bjh,
         |T5.fenfa_num_tth,
         |T6.fensi_num_bjh,
         |T7.fensi_num_tth
         |from
         |base_table T1
         |left outer join bjh_fawen T2 on T1.app_id=T2.app_id
         |left outer join tth_fawen T3 on T1.app_id=T3.app_id
         |left outer join bjh_fenfa T4 on T1.app_id=T4.app_id
         |left outer join tth_fenfa T5 on T1.app_id=T5.app_id
         |left outer join bjh_fensi_add T6 on T1.app_id=T6.app_id
         |left outer join tth_fensi_add T7 on T1.app_id=T7.app_id
       """.stripMargin).rdd.map(r => {
      r.mkString("\t")
    }).coalesce(5).saveAsTextFile(s"xxx")

解决办法：

去掉coalesce。

参考

https://www.e-learn.cn/content/wangluowenzhang/700757