Question

我需要加载在SparkR中创建的DataFrame以在Hive中加载。

#created a dataframe df_test
df_test <- createDataFrame(sqlContext, data.frame(mon = c(1,2,3,4,5), year = c(2011,2012,2013,2014,2015)))

#initialized the Hive context
>sc <- sparkR.init()
>hiveContext <- sparkRHive.init(sc)

#used the saveAsTable fn to save dataframe "df_test" in hive table named "table_hive"
>saveAsTable(df_test, "table_hive")

16/08/24 23:08:36错误RBackendHandler：13日的saveAsTable失败 invokeJava出错（isStatic = FALSE，objId $ id，methodName，...）： java.lang.RuntimeException：使用SQLContext创建的表必须是TEMPORARY。请改用HiveContext。在scala.sys.package $ .error（package.scala：27）在org.apache.spark.sql.execution.SparkStrategies $ DDLStrategy $ .apply（SparkStrategies.scala：392）在org.apache.spark.sql.catalyst.planning.QueryPlanner $$ anonfun $ 1.apply（QueryPlanner.scala：58）在org.apache.spark.sql.catalyst.planning.QueryPlanner $$ anonfun $ 1.apply（QueryPlanner.scala：58）在scala.collection.Iterator $$ anon $ 13.hasNext（Iterator.scala：371）在org.apache.spark.sql.catalyst.planning.QueryPlanner.plan（QueryPlanner.scala：59）在org.apache.spark.sql.execution.QueryExecution.sparkPlan $ lzycompute（QueryExecution.scala：47）在org.apache.spark.sql.execution.QueryExecution.sparkPlan（QueryExecution.scala：45）在org.apache.spark.sql.execution.QueryExecution.executedPlan $ lzycompute（QueryExecution.scala：52）在org.apache.spark.sql.execution.QueryExecution.executedPlan（QueryExecution.scala：52）在org.apache.spark.sql.execution

引发上述错误。请帮助。

Answer 1

在范围内HiveContext是不够的。每个数据框都绑定到特定的SQLContext / SparkSession实例，df_test显然创建的上下文不同于hiveContext

让我们举例说明：

 Welcome to
    ____              __ 
   / __/__  ___ _____/ /__ 
  _\ \/ _ \/ _ `/ __/  '_/ 
 /___/ .__/\_,_/_/ /_/\_\   version  1.6.1 
    /_/ 


 Spark context is available as sc, SQL context is available as sqlContext
> library(magrittr)
> createDataFrame(sqlContext, mtcars) %>% saveAsTable("foo")
16/08/24 20:22:13 ERROR RBackendHandler: saveAsTable on 22 failed
Error in invokeJava(isStatic = FALSE, objId$id, methodName, ...) : 
  java.lang.RuntimeException: Tables created with SQLContext must be TEMPORARY. Use a HiveContext instead.
    at scala.sys.package$.error(package.scala:27)
    at org.apache.spark.sql.execution.SparkStrategies$DDLStrategy$.apply(SparkStrategies.scala:392)
    at org.apache.spark.sql.catalyst.planning.QueryPlanner$$anonfun$1.apply(QueryPlanner.scala:58)
    at org.apache.spark.sql.catalyst.planning.QueryPlanner$$anonfun$1.apply(QueryPlanner.scala:58)
    at scala.collection.Iterator$$anon$12.hasNext(Iterator.scala:396)
    at org.apache.spark.sql.catalyst.planning.QueryPlanner.plan(QueryPlanner.scala:59)
    at org.apache.spark.sql.execution.QueryExecution.sparkPlan$lzycompute(QueryExecution.scala:47)
    at org.apache.spark.sql.execution.QueryExecution.sparkPlan(QueryExecution.scala:45)
    at org.apache.spark.sql.execution.QueryExecution.executedPlan$lzycompute(QueryExecution.scala:52)
    at org.apache.spark.sql.execution.QueryExecution.executedPlan(QueryExecution.scala:52)
    at org.apache.spark.sql.execu
>
> hiveContext <- sparkRHive.init(sc)
> createDataFrame(hiveContext, mtcars) %>% saveAsTable("foo")
NULL

在Hive中加载SparkR数据框

1 个答案: