count throws java.lang.NumberFormatException: 从启用了 inferSchema 的对象存储加载的文件上为 null

Question

当启用 inferSchema 时，从 IBM Blue Mix 对象存储加载的数据帧上的 count() 会抛出以下异常：

Name: org.apache.spark.SparkException
Message: Job aborted due to stage failure: Task 3 in stage 43.0 failed 10 times, most recent failure: Lost task 3.9 in stage 43.0 (TID 166, yp-spark-dal09-env5-0034): java.lang.NumberFormatException: null
    at java.lang.Integer.parseInt(Integer.java:554)
    at java.lang.Integer.parseInt(Integer.java:627)
    at scala.collection.immutable.StringLike$class.toInt(StringLike.scala:272)
    at scala.collection.immutable.StringOps.toInt(StringOps.scala:29)
    at org.apache.spark.sql.execution.datasources.csv.CSVTypeCast$.castTo(CSVInferSchema.scala:241)
    at org.apache.spark.sql.execution.datasources.csv.CSVRelation$$anonfun$csvParser.apply(CSVRelation.scala:116)
    at org.apache.spark.sql.execution.datasources.csv.CSVRelation$$anonfun$csvParser.apply(CSVRelation.scala:85)
    at org.apache.spark.sql.execution.datasources.csv.CSVFileFormat$$anonfun$buildReader$$anonfun$apply.apply(CSVFileFormat.scala:128)
    at org.apache.spark.sql.execution.datasources.csv.CSVFileFormat$$anonfun$buildReader$$anonfun$apply.apply(CSVFileFormat.scala:127)
    at scala.collection.Iterator$$anon.nextCur(Iterator.scala:434)
    at scala.collection.Iterator$$anon.hasNext(Iterator.scala:440)
    at scala.collection.Iterator$$anon.hasNext(Iterator.scala:408)
    at org.apache.spark.sql.execution.datasources.FileScanRDD$$anon.hasNext(FileScanRDD.scala:91)

如果我禁用 inferSchema，我不会得到上述异常。为什么我会收到此异常？默认情况下，如果启用 inferSchema，databricks 会读取多少行？

Answer 1

这实际上是拖入 spark 2.0 的 spark-csv 包 (null value still not correctly parsed #192) 的问题。已更正并推入 spark 2.1.

这是相关的 PR：[SPARK-18269][SQL] CSV datasource should read null properly when schema is lager than parsed tokens。

由于您已经在使用 spark 2.0，因此您可以轻松升级到 2.1 并删除 spark-csv 软件包。反正也不需要。

count throws java.lang.NumberFormatException: 从启用了 inferSchema 的对象存储加载的文件上为 null

count throws java.lang.NumberFormatException: null on the file loaded from object store with inferSchema enabled

apache-spark

apache-spark-sql

databricks

spark-csv