Hi, Joseph,
This is a known issue but not a bug.
This issue does not occur when you use interactive SparkR session, while it
does occur when you execute an R file.
The reason behind this is that in case you execute an R file, the R backend
launches before the R interpreter, so there is no opportunity for packages
specified with ‘sparkPackages’ to be processed.
For now, if you want to execute an R file with additional spark packages,
please use the “--packages” command line option.
> On Jun 17, 2016, at 10:46, Joseph <wxy81...@sina.com> wrote:
>
> Hi all,
>
> I find an issue in sparkR, maybe it's a bug:
>
> When I read csv file, it's normal to use the following way:
> ${SPARK_HOME}/bin/spark-submit --packages
> com.databricks:spark-csv_2.11:1.4.0 example.R
>
> But using the following way will give an error:
> sc <- sparkR.init(sparkPackages="com.databricks:spark-csv_2.11:1.4.0")
>
> 16/06/17 09:54:12 ERROR RBackendHandler: loadDF on
> org.apache.spark.sql.api.r.SQLUtils failed
> Error in invokeJava(isStatic = TRUE, className, methodName, ...) :
> java.lang.ClassNotFoundException: Failed to find data source: csv. Please
> find packages at http://spark-packages.org <http://spark-packages.org/>
> at
> org.apache.spark.sql.execution.datasources.ResolvedDataSource$.lookupDataSource(ResolvedDataSource.scala:77)
>
> It is obvious that the sparkR.init() does not load the specified package!
> -----------------------------------------------------------------------------------------------------------------------------------------
>
> Appendix:
> The complete code for example.R:
>
> if (nchar(Sys.getenv("SPARK_HOME")) < 1) {
> Sys.setenv(SPARK_HOME = "/home/hadoop/spark-1.6.1-bin-hadoop2.6")
> }
>
> library(SparkR, lib.loc = c(file.path(Sys.getenv("SPARK_HOME"), "R", "lib")))
>
> sc <- sparkR.init(master = "local[2]", sparkEnvir =
> list(spark.driver.memory="1g"),
> sparkPackages="com.databricks:spark-csv_2.11:1.4.0")
>
> sqlContext <- sparkRSQL.init(sc)
> people <- read.df(sqlContext,
> "file:/home/hadoop/spark-1.6.1-bin-hadoop2.6/data/mllib/sample_tree_data.csv",
> "csv")
> registerTempTable(people, "people")
> teenagers <- sql(sqlContext, "SELECT * FROM people")
> head(teenagers)
>
> Joseph
