Branch 2.3

LICENSE

@@ -263,7 +263,7 @@ The text of each license is also included at licenses/LICENSE-[project].txt.
      (New BSD license) Protocol Buffer Java API (org.spark-project.protobuf:protobuf-java:2.4.1-shaded - http://code.google.com/p/protobuf)
      (The BSD License) Fortran to Java ARPACK (net.sourceforge.f2j:arpack_combined_all:0.1 - http://f2j.sourceforge.net)
      (The BSD License) xmlenc Library (xmlenc:xmlenc:0.52 - http://xmlenc.sourceforge.net)
-     (The New BSD License) Py4J (net.sf.py4j:py4j:0.10.6 - http://py4j.sourceforge.net/)
+     (The New BSD License) Py4J (net.sf.py4j:py4j:0.10.7 - http://py4j.sourceforge.net/)
      (Two-clause BSD-style license) JUnit-Interface (com.novocode:junit-interface:0.10 - https://github.com/szeiger/junit-interface/)
      (BSD licence) sbt and sbt-launch-lib.bash
      (BSD 3 Clause) d3.min.js (https://github.com/mbostock/d3/blob/master/LICENSE)

R/pkg/DESCRIPTION

@@ -1,6 +1,6 @@
 Package: SparkR
 Type: Package
-Version: 2.3.0
+Version: 2.3.2
 Title: R Frontend for Apache Spark
 Description: Provides an R Frontend for Apache Spark.
 Authors@R: c(person("Shivaram", "Venkataraman", role = c("aut", "cre"),
@@ -13,6 +13,7 @@ Authors@R: c(person("Shivaram", "Venkataraman", role = c("aut", "cre"),
 License: Apache License (== 2.0)
 URL: http://www.apache.org/ http://spark.apache.org/
 BugReports: http://spark.apache.org/contributing.html
+SystemRequirements: Java (== 8)
 Depends:
     R (>= 3.0),
     methods

R/pkg/NAMESPACE

@@ -179,6 +179,7 @@ exportMethods("arrange",
               "with",
               "withColumn",
               "withColumnRenamed",
+              "withWatermark",
               "write.df",
               "write.jdbc",
               "write.json",

R/pkg/R/DataFrame.R

@@ -2090,7 +2090,8 @@ setMethod("selectExpr",
 #'
 #' @param x a SparkDataFrame.
 #' @param colName a column name.
-#' @param col a Column expression, or an atomic vector in the length of 1 as literal value.
+#' @param col a Column expression (which must refer only to this SparkDataFrame), or an atomic
+#' vector in the length of 1 as literal value.
 #' @return A SparkDataFrame with the new column added or the existing column replaced.
 #' @family SparkDataFrame functions
 #' @aliases withColumn,SparkDataFrame,character-method
@@ -2853,7 +2854,7 @@ setMethod("intersect",
 #' except
 #'
 #' Return a new SparkDataFrame containing rows in this SparkDataFrame
-#' but not in another SparkDataFrame. This is equivalent to \code{EXCEPT} in SQL.
+#' but not in another SparkDataFrame. This is equivalent to \code{EXCEPT DISTINCT} in SQL.
 #'
 #' @param x a SparkDataFrame.
 #' @param y a SparkDataFrame.
@@ -3054,10 +3055,10 @@ setMethod("describe",
 #' \item stddev
 #' \item min
 #' \item max
-#' \item arbitrary approximate percentiles specified as a percentage (eg, "75%")
+#' \item arbitrary approximate percentiles specified as a percentage (eg, "75\%")
 #' }
 #' If no statistics are given, this function computes count, mean, stddev, min,
-#' approximate quartiles (percentiles at 25%, 50%, and 75%), and max.
+#' approximate quartiles (percentiles at 25\%, 50\%, and 75\%), and max.
 #' This function is meant for exploratory data analysis, as we make no guarantee about the
 #' backward compatibility of the schema of the resulting Dataset. If you want to
 #' programmatically compute summary statistics, use the \code{agg} function instead.
@@ -3661,7 +3662,8 @@ setMethod("getNumPartitions",
 #' isStreaming
 #'
 #' Returns TRUE if this SparkDataFrame contains one or more sources that continuously return data
-#' as it arrives.
+#' as it arrives. A dataset that reads data from a streaming source must be executed as a
+#' \code{StreamingQuery} using \code{write.stream}.
 #'
 #' @param x A SparkDataFrame
 #' @return TRUE if this SparkDataFrame is from a streaming source
@@ -3707,7 +3709,17 @@ setMethod("isStreaming",
 #' @param df a streaming SparkDataFrame.
 #' @param source a name for external data source.
 #' @param outputMode one of 'append', 'complete', 'update'.
-#' @param ... additional argument(s) passed to the method.
+#' @param partitionBy a name or a list of names of columns to partition the output by on the file
+#'        system. If specified, the output is laid out on the file system similar to Hive's
+#'        partitioning scheme.
+#' @param trigger.processingTime a processing time interval as a string, e.g. '5 seconds',
+#'        '1 minute'. This is a trigger that runs a query periodically based on the processing
+#'        time. If value is '0 seconds', the query will run as fast as possible, this is the
+#'        default. Only one trigger can be set.
+#' @param trigger.once a logical, must be set to \code{TRUE}. This is a trigger that processes only
+#'        one batch of data in a streaming query then terminates the query. Only one trigger can be
+#'        set.
+#' @param ... additional external data source specific named options.
 #'
 #' @family SparkDataFrame functions
 #' @seealso \link{read.stream}
@@ -3725,7 +3737,8 @@ setMethod("isStreaming",
 #' # console
 #' q <- write.stream(wordCounts, "console", outputMode = "complete")
 #' # text stream
-#' q <- write.stream(df, "text", path = "/home/user/out", checkpointLocation = "/home/user/cp")
+#' q <- write.stream(df, "text", path = "/home/user/out", checkpointLocation = "/home/user/cp"
+#'                   partitionBy = c("year", "month"), trigger.processingTime = "30 seconds")
 #' # memory stream
 #' q <- write.stream(wordCounts, "memory", queryName = "outs", outputMode = "complete")
 #' head(sql("SELECT * from outs"))
@@ -3737,7 +3750,8 @@ setMethod("isStreaming",
 #' @note experimental
 setMethod("write.stream",
           signature(df = "SparkDataFrame"),
-          function(df, source = NULL, outputMode = NULL, ...) {
+          function(df, source = NULL, outputMode = NULL, partitionBy = NULL,
+                   trigger.processingTime = NULL, trigger.once = NULL, ...) {
             if (!is.null(source) && !is.character(source)) {
               stop("source should be character, NULL or omitted. It is the data source specified ",
                    "in 'spark.sql.sources.default' configuration by default.")
@@ -3748,12 +3762,43 @@ setMethod("write.stream",
             if (is.null(source)) {
               source <- getDefaultSqlSource()
             }
+            cols <- NULL
+            if (!is.null(partitionBy)) {
+              if (!all(sapply(partitionBy, function(c) { is.character(c) }))) {
+                stop("All partitionBy column names should be characters.")
+              }
+              cols <- as.list(partitionBy)
+            }
+            jtrigger <- NULL
+            if (!is.null(trigger.processingTime) && !is.na(trigger.processingTime)) {
+              if (!is.null(trigger.once)) {
+                stop("Multiple triggers not allowed.")
+              }
+              interval <- as.character(trigger.processingTime)
+              if (nchar(interval) == 0) {
+                stop("Value for trigger.processingTime must be a non-empty string.")
+              }
+              jtrigger <- handledCallJStatic("org.apache.spark.sql.streaming.Trigger",
+                                             "ProcessingTime",
+                                             interval)
+            } else if (!is.null(trigger.once) && !is.na(trigger.once)) {
+              if (!is.logical(trigger.once) || !trigger.once) {
+                stop("Value for trigger.once must be TRUE.")
+              }
+              jtrigger <- callJStatic("org.apache.spark.sql.streaming.Trigger", "Once")
+            }
             options <- varargsToStrEnv(...)
             write <- handledCallJMethod(df@sdf, "writeStream")
             write <- callJMethod(write, "format", source)
             if (!is.null(outputMode)) {
               write <- callJMethod(write, "outputMode", outputMode)
             }
+            if (!is.null(cols)) {
+              write <- callJMethod(write, "partitionBy", cols)
+            }
+            if (!is.null(jtrigger)) {
+              write <- callJMethod(write, "trigger", jtrigger)
+            }
             write <- callJMethod(write, "options", options)
             ssq <- handledCallJMethod(write, "start")
             streamingQuery(ssq)
@@ -3967,3 +4012,47 @@ setMethod("broadcast",
             sdf <- callJStatic("org.apache.spark.sql.functions", "broadcast", x@sdf)
             dataFrame(sdf)
           })
+
+#' withWatermark
+#'
+#' Defines an event time watermark for this streaming SparkDataFrame. A watermark tracks a point in
+#' time before which we assume no more late data is going to arrive.
+#'
+#' Spark will use this watermark for several purposes:
+#' \itemize{
+#'  \item To know when a given time window aggregation can be finalized and thus can be emitted
+#' when using output modes that do not allow updates.
+#'  \item To minimize the amount of state that we need to keep for on-going aggregations.
+#' }
+#' The current watermark is computed by looking at the \code{MAX(eventTime)} seen across
+#' all of the partitions in the query minus a user specified \code{delayThreshold}. Due to the cost
+#' of coordinating this value across partitions, the actual watermark used is only guaranteed
+#' to be at least \code{delayThreshold} behind the actual event time.  In some cases we may still
+#' process records that arrive more than \code{delayThreshold} late.
+#'
+#' @param x a streaming SparkDataFrame
+#' @param eventTime a string specifying the name of the Column that contains the event time of the
+#'                  row.
+#' @param delayThreshold a string specifying the minimum delay to wait to data to arrive late,
+#'                       relative to the latest record that has been processed in the form of an
+#'                       interval (e.g. "1 minute" or "5 hours"). NOTE: This should not be negative.
+#' @return a SparkDataFrame.
+#' @aliases withWatermark,SparkDataFrame,character,character-method
+#' @family SparkDataFrame functions
+#' @rdname withWatermark
+#' @name withWatermark
+#' @export
+#' @examples
+#' \dontrun{
+#' sparkR.session()
+#' schema <- structType(structField("time", "timestamp"), structField("value", "double"))
+#' df <- read.stream("json", path = jsonDir, schema = schema, maxFilesPerTrigger = 1)
+#' df <- withWatermark(df, "time", "10 minutes")
+#' }
+#' @note withWatermark since 2.3.0
+setMethod("withWatermark",
+          signature(x = "SparkDataFrame", eventTime = "character", delayThreshold = "character"),
+          function(x, eventTime, delayThreshold) {
+            sdf <- callJMethod(x@sdf, "withWatermark", eventTime, delayThreshold)
+            dataFrame(sdf)
+          })

R/pkg/R/SQLContext.R

@@ -727,7 +727,9 @@ read.jdbc <- function(url, tableName,
 #' @param schema The data schema defined in structType or a DDL-formatted string, this is
 #'               required for file-based streaming data source
 #' @param ... additional external data source specific named options, for instance \code{path} for
-#'        file-based streaming data source
+#'        file-based streaming data source. \code{timeZone} to indicate a timezone to be used to
+#'        parse timestamps in the JSON/CSV data sources or partition values; If it isn't set, it
+#'        uses the default value, session local timezone.
 #' @return SparkDataFrame
 #' @rdname read.stream
 #' @name read.stream

R/pkg/R/client.R

@@ -19,7 +19,7 @@
 
 # Creates a SparkR client connection object
 # if one doesn't already exist
-connectBackend <- function(hostname, port, timeout) {
+connectBackend <- function(hostname, port, timeout, authSecret) {
   if (exists(".sparkRcon", envir = .sparkREnv)) {
     if (isOpen(.sparkREnv[[".sparkRCon"]])) {
       cat("SparkRBackend client connection already exists\n")
@@ -29,7 +29,7 @@ connectBackend <- function(hostname, port, timeout) {
 
   con <- socketConnection(host = hostname, port = port, server = FALSE,
                           blocking = TRUE, open = "wb", timeout = timeout)
-
+  doServerAuth(con, authSecret)
   assign(".sparkRCon", con, envir = .sparkREnv)
   con
 }
@@ -60,13 +60,49 @@ generateSparkSubmitArgs <- function(args, sparkHome, jars, sparkSubmitOpts, pack
   combinedArgs
 }
 
+checkJavaVersion <- function() {
+  javaBin <- "java"
+  javaHome <- Sys.getenv("JAVA_HOME")
+  javaReqs <- utils::packageDescription(utils::packageName(), fields = c("SystemRequirements"))
+  sparkJavaVersion <- as.numeric(tail(strsplit(javaReqs, "[(=)]")[[1]], n = 1L))
+  if (javaHome != "") {
+    javaBin <- file.path(javaHome, "bin", javaBin)
+  }
+
+  # If java is missing from PATH, we get an error in Unix and a warning in Windows
+  javaVersionOut <- tryCatch(
+      launchScript(javaBin, "-version", wait = TRUE, stdout = TRUE, stderr = TRUE),
+                   error = function(e) {
+                     stop("Java version check failed. Please make sure Java is installed",
+                          " and set JAVA_HOME to point to the installation directory.", e)
+                   },
+                   warning = function(w) {
+                     stop("Java version check failed. Please make sure Java is installed",
+                          " and set JAVA_HOME to point to the installation directory.", w)
+                   })
+  javaVersionFilter <- Filter(
+      function(x) {
+        grepl(" version", x)
+      }, javaVersionOut)
+
+  javaVersionStr <- strsplit(javaVersionFilter[[1]], "[\"]")[[1L]][2]
+  # javaVersionStr is of the form 1.8.0_92.
+  # Extract 8 from it to compare to sparkJavaVersion
+  javaVersionNum <- as.integer(strsplit(javaVersionStr, "[.]")[[1L]][2])
+  if (javaVersionNum != sparkJavaVersion) {
+    stop(paste("Java version", sparkJavaVersion, "is required for this package; found version:",
+               javaVersionStr))
+  }
+}
+
 launchBackend <- function(args, sparkHome, jars, sparkSubmitOpts, packages) {
   sparkSubmitBinName <- determineSparkSubmitBin()
   if (sparkHome != "") {
     sparkSubmitBin <- file.path(sparkHome, "bin", sparkSubmitBinName)
   } else {
     sparkSubmitBin <- sparkSubmitBinName
   }
+
   combinedArgs <- generateSparkSubmitArgs(args, sparkHome, jars, sparkSubmitOpts, packages)
   cat("Launching java with spark-submit command", sparkSubmitBin, combinedArgs, "\n")
   invisible(launchScript(sparkSubmitBin, combinedArgs))

R/pkg/R/column.R

@@ -164,12 +164,18 @@ setMethod("alias",
 #' @aliases substr,Column-method
 #'
 #' @param x a Column.
-#' @param start starting position.
+#' @param start starting position. It should be 1-base.
 #' @param stop ending position.
+#' @examples
+#' \dontrun{
+#' df <- createDataFrame(list(list(a="abcdef")))
+#' collect(select(df, substr(df$a, 1, 4))) # the result is `abcd`.
+#' collect(select(df, substr(df$a, 2, 4))) # the result is `bcd`.
+#' }
 #' @note substr since 1.4.0
 setMethod("substr", signature(x = "Column"),
           function(x, start, stop) {
-            jc <- callJMethod(x@jc, "substr", as.integer(start - 1), as.integer(stop - start + 1))
+            jc <- callJMethod(x@jc, "substr", as.integer(start), as.integer(stop - start + 1))
             column(jc)
           })
 

R/pkg/R/deserialize.R

@@ -60,14 +60,18 @@ readTypedObject <- function(con, type) {
     stop(paste("Unsupported type for deserialization", type)))
 }
 
-readString <- function(con) {
-  stringLen <- readInt(con)
-  raw <- readBin(con, raw(), stringLen, endian = "big")
+readStringData <- function(con, len) {
+  raw <- readBin(con, raw(), len, endian = "big")
   string <- rawToChar(raw)
   Encoding(string) <- "UTF-8"
   string
 }
 
+readString <- function(con) {
+  stringLen <- readInt(con)
+  readStringData(con, stringLen)
+}
+
 readInt <- function(con) {
   readBin(con, integer(), n = 1, endian = "big")
 }