spark = SparkSession. ...

# Read text from socket
socketDF = spark \
    .readStream \
    .format("socket") \
    .option("host", "localhost") \
    .option("port", 9999) \
    .load()

socketDF.isStreaming()    # Returns True for DataFrames that have streaming sources

socketDF.printSchema()

# Read all the csv files written atomically in a directory
userSchema = StructType().add("name", "string").add("age", "integer")
csvDF = spark \
    .readStream \
    .option("sep", ";") \
    .schema(userSchema) \
    .csv("/path/to/directory")  # Equivalent to format("csv").load("/path/to/directory")

val spark: SparkSession = ...

// Read text from socket
val socketDF = spark
  .readStream
  .format("socket")
  .option("host", "localhost")
  .option("port", 9999)
  .load()

socketDF.isStreaming    // Returns True for DataFrames that have streaming sources

socketDF.printSchema

// Read all the csv files written atomically in a directory
val userSchema = new StructType().add("name", "string").add("age", "integer")
val csvDF = spark
  .readStream
  .option("sep", ";")
  .schema(userSchema)      // Specify schema of the csv files
  .csv("/path/to/directory")    // Equivalent to format("csv").load("/path/to/directory")

SparkSession spark = ...

// Read text from socket
Dataset<Row> socketDF = spark
  .readStream()
  .format("socket")
  .option("host", "localhost")
  .option("port", 9999)
  .load();

socketDF.isStreaming();    // Returns True for DataFrames that have streaming sources

socketDF.printSchema();

// Read all the csv files written atomically in a directory
StructType userSchema = new StructType().add("name", "string").add("age", "integer");
Dataset<Row> csvDF = spark
  .readStream()
  .option("sep", ";")
  .schema(userSchema)      // Specify schema of the csv files
  .csv("/path/to/directory");    // Equivalent to format("csv").load("/path/to/directory")

sparkR.session(...)

# Read text from socket
socketDF <- read.stream("socket", host = hostname, port = port)

isStreaming(socketDF)    # Returns TRUE for SparkDataFrames that have streaming sources

printSchema(socketDF)

# Read all the csv files written atomically in a directory
schema <- structType(structField("name", "string"),
                     structField("age", "integer"))
csvDF <- read.stream("csv", path = "/path/to/directory", schema = schema, sep = ";")

df = ...  # streaming DataFrame with IOT device data with schema { device: string, deviceType: string, signal: double, time: DateType }

# Select the devices which have signal more than 10
df.select("device").where("signal > 10")

# Running count of the number of updates for each device type
df.groupBy("deviceType").count()

case class DeviceData(device: String, deviceType: String, signal: Double, time: DateTime)

val df: DataFrame = ... // streaming DataFrame with IOT device data with schema { device: string, deviceType: string, signal: double, time: string }
val ds: Dataset[DeviceData] = df.as[DeviceData]    // streaming Dataset with IOT device data

// Select the devices which have signal more than 10
df.select("device").where("signal > 10")      // using untyped APIs
ds.filter(_.signal > 10).map(_.device)         // using typed APIs

// Running count of the number of updates for each device type
df.groupBy("deviceType").count()                          // using untyped API

// Running average signal for each device type
import org.apache.spark.sql.expressions.scalalang.typed
ds.groupByKey(_.deviceType).agg(typed.avg(_.signal))    // using typed API

import org.apache.spark.api.java.function.*;
import org.apache.spark.sql.*;
import org.apache.spark.sql.expressions.javalang.typed;
import org.apache.spark.sql.catalyst.encoders.ExpressionEncoder;

public class DeviceData {
  private String device;
  private String deviceType;
  private Double signal;
  private java.sql.Date time;
  ...
  // Getter and setter methods for each field
}

Dataset<Row> df = ...;    // streaming DataFrame with IOT device data with schema { device: string, type: string, signal: double, time: DateType }
Dataset<DeviceData> ds = df.as(ExpressionEncoder.javaBean(DeviceData.class)); // streaming Dataset with IOT device data

// Select the devices which have signal more than 10
df.select("device").where("signal > 10"); // using untyped APIs
ds.filter((FilterFunction<DeviceData>) value -> value.getSignal() > 10)
  .map((MapFunction<DeviceData, String>) value -> value.getDevice(), Encoders.STRING());

// Running count of the number of updates for each device type
df.groupBy("deviceType").count(); // using untyped API

// Running average signal for each device type
ds.groupByKey((MapFunction<DeviceData, String>) value -> value.getDeviceType(), Encoders.STRING())
  .agg(typed.avg((MapFunction<DeviceData, Double>) value -> value.getSignal()));

df <- ...  # streaming DataFrame with IOT device data with schema { device: string, deviceType: string, signal: double, time: DateType }

# Select the devices which have signal more than 10
select(where(df, "signal > 10"), "device")

# Running count of the number of updates for each device type
count(groupBy(df, "deviceType"))

df.createOrReplaceTempView("updates")
spark.sql("select count(*) from updates")  # returns another streaming DF

df.createOrReplaceTempView("updates")
spark.sql("select count(*) from updates")  // returns another streaming DF

df.createOrReplaceTempView("updates");
spark.sql("select count(*) from updates");  // returns another streaming DF

createOrReplaceTempView(df, "updates")
sql("select count(*) from updates")

df.isStreaming()

df.isStreaming

df.isStreaming()

isStreaming(df)

words = ...  # streaming DataFrame of schema { timestamp: Timestamp, word: String }

# Group the data by window and word and compute the count of each group
windowedCounts = words.groupBy(
    window(words.timestamp, "10 minutes", "5 minutes"),
    words.word
).count()

import spark.implicits._

val words = ... // streaming DataFrame of schema { timestamp: Timestamp, word: String }

// Group the data by window and word and compute the count of each group
val windowedCounts = words.groupBy(
  window($"timestamp", "10 minutes", "5 minutes"),
  $"word"
).count()

Dataset<Row> words = ... // streaming DataFrame of schema { timestamp: Timestamp, word: String }

// Group the data by window and word and compute the count of each group
Dataset<Row> windowedCounts = words.groupBy(
  functions.window(words.col("timestamp"), "10 minutes", "5 minutes"),
  words.col("word")
).count();

words <- ...  # streaming DataFrame of schema { timestamp: Timestamp, word: String }

# Group the data by window and word and compute the count of each group
windowedCounts <- count(
                    groupBy(
                      words,
                      window(words$timestamp, "10 minutes", "5 minutes"),
                      words$word))

words = ...  # streaming DataFrame of schema { timestamp: Timestamp, word: String }

# Group the data by window and word and compute the count of each group
windowedCounts = words \
    .withWatermark("timestamp", "10 minutes") \
    .groupBy(
        window(words.timestamp, "10 minutes", "5 minutes"),
        words.word) \
    .count()

import spark.implicits._

val words = ... // streaming DataFrame of schema { timestamp: Timestamp, word: String }

// Group the data by window and word and compute the count of each group
val windowedCounts = words
    .withWatermark("timestamp", "10 minutes")
    .groupBy(
        window($"timestamp", "10 minutes", "5 minutes"),
        $"word")
    .count()

Dataset<Row> words = ... // streaming DataFrame of schema { timestamp: Timestamp, word: String }

// Group the data by window and word and compute the count of each group
Dataset<Row> windowedCounts = words
    .withWatermark("timestamp", "10 minutes")
    .groupBy(
        window(col("timestamp"), "10 minutes", "5 minutes"),
        col("word"))
    .count();

words <- ...  # streaming DataFrame of schema { timestamp: Timestamp, word: String }

# Group the data by window and word and compute the count of each group

words <- withWatermark(words, "timestamp", "10 minutes")
windowedCounts <- count(
                    groupBy(
                      words,
                      window(words$timestamp, "10 minutes", "5 minutes"),
                      words$word))

events = ...  # streaming DataFrame of schema { timestamp: Timestamp, userId: String }

# Group the data by session window and userId, and compute the count of each group
sessionizedCounts = events \
    .withWatermark("timestamp", "10 minutes") \
    .groupBy(
        session_window(events.timestamp, "5 minutes"),
        events.userId) \
    .count()

import spark.implicits._

val events = ... // streaming DataFrame of schema { timestamp: Timestamp, userId: String }

// Group the data by session window and userId, and compute the count of each group
val sessionizedCounts = events
    .withWatermark("timestamp", "10 minutes")
    .groupBy(
        session_window($"timestamp", "5 minutes"),
        $"userId")
    .count()

Dataset<Row> events = ... // streaming DataFrame of schema { timestamp: Timestamp, userId: String }

// Group the data by session window and userId, and compute the count of each group
Dataset<Row> sessionizedCounts = events
    .withWatermark("timestamp", "10 minutes")
    .groupBy(
        session_window(col("timestamp"), "5 minutes"),
        col("userId"))
    .count();

from pyspark.sql import functions as sf

events = ...  # streaming DataFrame of schema { timestamp: Timestamp, userId: String }

session_window = session_window(events.timestamp, \
    sf.when(events.userId == "user1", "5 seconds") \
    .when(events.userId == "user2", "20 seconds").otherwise("5 minutes"))

# Group the data by session window and userId, and compute the count of each group
sessionizedCounts = events \
    .withWatermark("timestamp", "10 minutes") \
    .groupBy(
        session_window,
        events.userId) \
    .count()

import spark.implicits._

val events = ... // streaming DataFrame of schema { timestamp: Timestamp, userId: String }

val sessionWindow = session_window($"timestamp", when($"userId" === "user1", "5 seconds")
  .when($"userId" === "user2", "20 seconds")
  .otherwise("5 minutes"))

// Group the data by session window and userId, and compute the count of each group
val sessionizedCounts = events
    .withWatermark("timestamp", "10 minutes")
    .groupBy(
        Column(sessionWindow),
        $"userId")
    .count()

Dataset<Row> events = ... // streaming DataFrame of schema { timestamp: Timestamp, userId: String }

SessionWindow sessionWindow = session_window(col("timestamp"), when(col("userId").equalTo("user1"), "5 seconds")
  .when(col("userId").equalTo("user2"), "20 seconds")
  .otherwise("5 minutes"))

// Group the data by session window and userId, and compute the count of each group
Dataset<Row> sessionizedCounts = events
    .withWatermark("timestamp", "10 minutes")
    .groupBy(
        new Column(sessionWindow),
        col("userId"))
    .count();

words = ...  # streaming DataFrame of schema { timestamp: Timestamp, word: String }

# Group the data by window and word and compute the count of each group
windowedCounts = words.groupBy(
    window(words.timestamp, "10 minutes", "5 minutes"),
    words.word
).count()

# Group the windowed data by another window and word and compute the count of each group
anotherWindowedCounts = windowedCounts.groupBy(
    window(window_time(windowedCounts.window), "1 hour"),
    windowedCounts.word
).count()

import spark.implicits._

val words = ... // streaming DataFrame of schema { timestamp: Timestamp, word: String }

// Group the data by window and word and compute the count of each group
val windowedCounts = words.groupBy(
  window($"timestamp", "10 minutes", "5 minutes"),
  $"word"
).count()

// Group the windowed data by another window and word and compute the count of each group
val anotherWindowedCounts = windowedCounts.groupBy(
  window(window_time($"window"), "1 hour"),
  $"word"
).count()

Dataset<Row> words = ... // streaming DataFrame of schema { timestamp: Timestamp, word: String }

// Group the data by window and word and compute the count of each group
Dataset<Row> windowedCounts = words.groupBy(
  functions.window(words.col("timestamp"), "10 minutes", "5 minutes"),
  words.col("word")
).count();

// Group the windowed data by another window and word and compute the count of each group
Dataset<Row> anotherWindowedCounts = windowedCounts.groupBy(
  functions.window(functions.window_time("window"), "1 hour"),
  windowedCounts.col("word")
).count();

words = ...  # streaming DataFrame of schema { timestamp: Timestamp, word: String }

# Group the data by window and word and compute the count of each group
windowedCounts = words.groupBy(
    window(words.timestamp, "10 minutes", "5 minutes"),
    words.word
).count()

# Group the windowed data by another window and word and compute the count of each group
anotherWindowedCounts = windowedCounts.groupBy(
    window(windowedCounts.window, "1 hour"),
    windowedCounts.word
).count()

import spark.implicits._

val words = ... // streaming DataFrame of schema { timestamp: Timestamp, word: String }

// Group the data by window and word and compute the count of each group
val windowedCounts = words.groupBy(
  window($"timestamp", "10 minutes", "5 minutes"),
  $"word"
).count()

// Group the windowed data by another window and word and compute the count of each group
val anotherWindowedCounts = windowedCounts.groupBy(
  window($"window", "1 hour"),
  $"word"
).count()

Dataset<Row> words = ... // streaming DataFrame of schema { timestamp: Timestamp, word: String }

// Group the data by window and word and compute the count of each group
Dataset<Row> windowedCounts = words.groupBy(
  functions.window(words.col("timestamp"), "10 minutes", "5 minutes"),
  words.col("word")
).count();

// Group the windowed data by another window and word and compute the count of each group
Dataset<Row> anotherWindowedCounts = windowedCounts.groupBy(
  functions.window("window", "1 hour"),
  windowedCounts.col("word")
).count();

staticDf = spark.read. ...
streamingDf = spark.readStream. ...
streamingDf.join(staticDf, "type")  # inner equi-join with a static DF
streamingDf.join(staticDf, "type", "left_outer")  # left outer join with a static DF

val staticDf = spark.read. ...
val streamingDf = spark.readStream. ...

streamingDf.join(staticDf, "type")          // inner equi-join with a static DF
streamingDf.join(staticDf, "type", "left_outer")  // left outer join with a static DF

Dataset<Row> staticDf = spark.read(). ...;
Dataset<Row> streamingDf = spark.readStream(). ...;
streamingDf.join(staticDf, "type");         // inner equi-join with a static DF
streamingDf.join(staticDf, "type", "left_outer");  // left outer join with a static DF

staticDf <- read.df(...)
streamingDf <- read.stream(...)
joined <- merge(streamingDf, staticDf, sort = FALSE)  # inner equi-join with a static DF
joined <- join(
            streamingDf,
            staticDf,
            streamingDf$value == staticDf$value,
            "left_outer")  # left outer join with a static DF

from pyspark.sql.functions import expr

impressions = spark.readStream. ...
clicks = spark.readStream. ...

# Apply watermarks on event-time columns
impressionsWithWatermark = impressions.withWatermark("impressionTime", "2 hours")
clicksWithWatermark = clicks.withWatermark("clickTime", "3 hours")

# Join with event-time constraints
impressionsWithWatermark.join(
  clicksWithWatermark,
  expr("""
    clickAdId = impressionAdId AND
    clickTime >= impressionTime AND
    clickTime <= impressionTime + interval 1 hour
    """)
)

import org.apache.spark.sql.functions.expr

val impressions = spark.readStream. ...
val clicks = spark.readStream. ...

// Apply watermarks on event-time columns
val impressionsWithWatermark = impressions.withWatermark("impressionTime", "2 hours")
val clicksWithWatermark = clicks.withWatermark("clickTime", "3 hours")

// Join with event-time constraints
impressionsWithWatermark.join(
  clicksWithWatermark,
  expr("""
    clickAdId = impressionAdId AND
    clickTime >= impressionTime AND
    clickTime <= impressionTime + interval 1 hour
    """)
)

import static org.apache.spark.sql.functions.expr

Dataset<Row> impressions = spark.readStream(). ...
Dataset<Row> clicks = spark.readStream(). ...

// Apply watermarks on event-time columns
Dataset<Row> impressionsWithWatermark = impressions.withWatermark("impressionTime", "2 hours");
Dataset<Row> clicksWithWatermark = clicks.withWatermark("clickTime", "3 hours");

// Join with event-time constraints
impressionsWithWatermark.join(
  clicksWithWatermark,
  expr(
    "clickAdId = impressionAdId AND " +
    "clickTime >= impressionTime AND " +
    "clickTime <= impressionTime + interval 1 hour ")
);

impressions <- read.stream(...)
clicks <- read.stream(...)

# Apply watermarks on event-time columns
impressionsWithWatermark <- withWatermark(impressions, "impressionTime", "2 hours")
clicksWithWatermark <- withWatermark(clicks, "clickTime", "3 hours")

# Join with event-time constraints
joined <- join(
  impressionsWithWatermark,
  clicksWithWatermark,
  expr(
    paste(
      "clickAdId = impressionAdId AND",
      "clickTime >= impressionTime AND",
      "clickTime <= impressionTime + interval 1 hour"
)))

impressionsWithWatermark.join(
  clicksWithWatermark,
  expr("""
    clickAdId = impressionAdId AND
    clickTime >= impressionTime AND
    clickTime <= impressionTime + interval 1 hour
    """),
  "leftOuter"                 # can be "inner", "leftOuter", "rightOuter", "fullOuter", "leftSemi"
)

impressionsWithWatermark.join(
  clicksWithWatermark,
  expr("""
    clickAdId = impressionAdId AND
    clickTime >= impressionTime AND
    clickTime <= impressionTime + interval 1 hour
    """),
  joinType = "leftOuter"      // can be "inner", "leftOuter", "rightOuter", "fullOuter", "leftSemi"
 )

impressionsWithWatermark.join(
  clicksWithWatermark,
  expr(
    "clickAdId = impressionAdId AND " +
    "clickTime >= impressionTime AND " +
    "clickTime <= impressionTime + interval 1 hour "),
  "leftOuter"                 // can be "inner", "leftOuter", "rightOuter", "fullOuter", "leftSemi"
);

joined <- join(
  impressionsWithWatermark,
  clicksWithWatermark,
  expr(
    paste(
      "clickAdId = impressionAdId AND",
      "clickTime >= impressionTime AND",
      "clickTime <= impressionTime + interval 1 hour"),
  "left_outer"                 # can be "inner", "left_outer", "right_outer", "full_outer", "left_semi"
))

clicksWindow = clicksWithWatermark.groupBy(
  clicksWithWatermark.clickAdId,
  window(clicksWithWatermark.clickTime, "1 hour")
).count()

impressionsWindow = impressionsWithWatermark.groupBy(
  impressionsWithWatermark.impressionAdId,
  window(impressionsWithWatermark.impressionTime, "1 hour")
).count()

clicksWindow.join(impressionsWindow, "window", "inner")

val clicksWindow = clicksWithWatermark
  .groupBy(window("clickTime", "1 hour"))
  .count()

val impressionsWindow = impressionsWithWatermark
  .groupBy(window("impressionTime", "1 hour"))
  .count()

clicksWindow.join(impressionsWindow, "window", "inner")

Dataset<Row> clicksWindow = clicksWithWatermark
  .groupBy(functions.window(clicksWithWatermark.col("clickTime"), "1 hour"))
  .count();

Dataset<Row> impressionsWindow = impressionsWithWatermark
  .groupBy(functions.window(impressionsWithWatermark.col("impressionTime"), "1 hour"))
  .count();

clicksWindow.join(impressionsWindow, "window", "inner");

joined = impressionsWithWatermark.join(
  clicksWithWatermark,
  expr("""
    clickAdId = impressionAdId AND
    clickTime >= impressionTime AND
    clickTime <= impressionTime + interval 1 hour
    """),
  "leftOuter"                 # can be "inner", "leftOuter", "rightOuter", "fullOuter", "leftSemi"
)

joined.groupBy(
  joined.clickAdId,
  window(joined.clickTime, "1 hour")
).count()

val joined = impressionsWithWatermark.join(
  clicksWithWatermark,
  expr("""
    clickAdId = impressionAdId AND
    clickTime >= impressionTime AND
    clickTime <= impressionTime + interval 1 hour
  """),
  joinType = "leftOuter"      // can be "inner", "leftOuter", "rightOuter", "fullOuter", "leftSemi"
)

joined
  .groupBy($"clickAdId", window($"clickTime", "1 hour"))
  .count()

Dataset<Row> joined = impressionsWithWatermark.join(
  clicksWithWatermark,
  expr(
    "clickAdId = impressionAdId AND " +
    "clickTime >= impressionTime AND " +
    "clickTime <= impressionTime + interval 1 hour "),
  "leftOuter"                 // can be "inner", "leftOuter", "rightOuter", "fullOuter", "leftSemi"
);

joined
  .groupBy(joined.col("clickAdId"), functions.window(joined.col("clickTime"), "1 hour"))
  .count();

streamingDf = spark.readStream. ...

# Without watermark using guid column
streamingDf.dropDuplicates(["guid"])

# With watermark using guid and eventTime columns
streamingDf \
  .withWatermark("eventTime", "10 seconds") \
  .dropDuplicates(["guid", "eventTime"])

val streamingDf = spark.readStream. ...  // columns: guid, eventTime, ...

// Without watermark using guid column
streamingDf.dropDuplicates("guid")

// With watermark using guid and eventTime columns
streamingDf
  .withWatermark("eventTime", "10 seconds")
  .dropDuplicates("guid", "eventTime")

Dataset<Row> streamingDf = spark.readStream(). ...;  // columns: guid, eventTime, ...

// Without watermark using guid column
streamingDf.dropDuplicates("guid");

// With watermark using guid and eventTime columns
streamingDf
  .withWatermark("eventTime", "10 seconds")
  .dropDuplicates("guid", "eventTime");

streamingDf <- read.stream(...)

# Without watermark using guid column
streamingDf <- dropDuplicates(streamingDf, "guid")

# With watermark using guid and eventTime columns
streamingDf <- withWatermark(streamingDf, "eventTime", "10 seconds")
streamingDf <- dropDuplicates(streamingDf, "guid", "eventTime")

streamingDf = spark.readStream. ...

# deduplicate using guid column with watermark based on eventTime column
streamingDf \
  .withWatermark("eventTime", "10 hours") \
  .dropDuplicatesWithinWatermark(["guid"])

val streamingDf = spark.readStream. ...  // columns: guid, eventTime, ...

// deduplicate using guid column with watermark based on eventTime column
streamingDf
  .withWatermark("eventTime", "10 hours")
  .dropDuplicatesWithinWatermark("guid")

Dataset<Row> streamingDf = spark.readStream(). ...;  // columns: guid, eventTime, ...

// deduplicate using guid column with watermark based on eventTime column
streamingDf
  .withWatermark("eventTime", "10 hours")
  .dropDuplicatesWithinWatermark("guid");

inputStream1.withWatermark("eventTime1", "1 hour")
  .join(
    inputStream2.withWatermark("eventTime2", "2 hours"),
    joinCondition)

# ========== DF with no aggregations ==========
noAggDF = deviceDataDf.select("device").where("signal > 10")

# Print new data to console
noAggDF \
    .writeStream \
    .format("console") \
    .start()

# Write new data to Parquet files
noAggDF \
    .writeStream \
    .format("parquet") \
    .option("checkpointLocation", "path/to/checkpoint/dir") \
    .option("path", "path/to/destination/dir") \
    .start()

# ========== DF with aggregation ==========
aggDF = df.groupBy("device").count()

# Print updated aggregations to console
aggDF \
    .writeStream \
    .outputMode("complete") \
    .format("console") \
    .start()

# Have all the aggregates in an in-memory table. The query name will be the table name
aggDF \
    .writeStream \
    .queryName("aggregates") \
    .outputMode("complete") \
    .format("memory") \
    .start()

spark.sql("select * from aggregates").show()   # interactively query in-memory table

// ========== DF with no aggregations ==========
val noAggDF = deviceDataDf.select("device").where("signal > 10")

// Print new data to console
noAggDF
  .writeStream
  .format("console")
  .start()

// Write new data to Parquet files
noAggDF
  .writeStream
  .format("parquet")
  .option("checkpointLocation", "path/to/checkpoint/dir")
  .option("path", "path/to/destination/dir")
  .start()

// ========== DF with aggregation ==========
val aggDF = df.groupBy("device").count()

// Print updated aggregations to console
aggDF
  .writeStream
  .outputMode("complete")
  .format("console")
  .start()

// Have all the aggregates in an in-memory table
aggDF
  .writeStream
  .queryName("aggregates")    // this query name will be the table name
  .outputMode("complete")
  .format("memory")
  .start()

spark.sql("select * from aggregates").show()   // interactively query in-memory table

// ========== DF with no aggregations ==========
Dataset<Row> noAggDF = deviceDataDf.select("device").where("signal > 10");

// Print new data to console
noAggDF
  .writeStream()
  .format("console")
  .start();

// Write new data to Parquet files
noAggDF
  .writeStream()
  .format("parquet")
  .option("checkpointLocation", "path/to/checkpoint/dir")
  .option("path", "path/to/destination/dir")
  .start();

// ========== DF with aggregation ==========
Dataset<Row> aggDF = df.groupBy("device").count();

// Print updated aggregations to console
aggDF
  .writeStream()
  .outputMode("complete")
  .format("console")
  .start();

// Have all the aggregates in an in-memory table
aggDF
  .writeStream()
  .queryName("aggregates")    // this query name will be the table name
  .outputMode("complete")
  .format("memory")
  .start();

spark.sql("select * from aggregates").show();   // interactively query in-memory table

# ========== DF with no aggregations ==========
noAggDF <- select(where(deviceDataDf, "signal > 10"), "device")

# Print new data to console
write.stream(noAggDF, "console")

# Write new data to Parquet files
write.stream(noAggDF,
             "parquet",
             path = "path/to/destination/dir",
             checkpointLocation = "path/to/checkpoint/dir")

# ========== DF with aggregation ==========
aggDF <- count(groupBy(df, "device"))

# Print updated aggregations to console
write.stream(aggDF, "console", outputMode = "complete")

# Have all the aggregates in an in memory table. The query name will be the table name
write.stream(aggDF, "memory", queryName = "aggregates", outputMode = "complete")

# Interactively query in-memory table
head(sql("select * from aggregates"))

def foreach_batch_function(df, epoch_id):
    # Transform and write batchDF
    pass

streamingDF.writeStream.foreachBatch(foreach_batch_function).start()

streamingDF.writeStream.foreachBatch { (batchDF: DataFrame, batchId: Long) =>
  // Transform and write batchDF
}.start()

streamingDatasetOfString.writeStream().foreachBatch(
  new VoidFunction2<Dataset<String>, Long>() {
    public void call(Dataset<String> dataset, Long batchId) {
      // Transform and write batchDF
    }
  }
).start();

streamingDF.writeStream.foreachBatch { (batchDF: DataFrame, batchId: Long) =>
  batchDF.persist()
  batchDF.write.format(...).save(...)  // location 1
  batchDF.write.format(...).save(...)  // location 2
  batchDF.unpersist()
}

def process_row(row):
    # Write row to storage
    pass

query = streamingDF.writeStream.foreach(process_row).start()

class ForeachWriter:
    def open(self, partition_id, epoch_id):
        # Open connection. This method is optional in Python.
        pass

    def process(self, row):
        # Write row to connection. This method is NOT optional in Python.
        pass

    def close(self, error):
        # Close the connection. This method in optional in Python.
        pass

query = streamingDF.writeStream.foreach(ForeachWriter()).start()

streamingDatasetOfString.writeStream.foreach(
  new ForeachWriter[String] {

    def open(partitionId: Long, version: Long): Boolean = {
      // Open connection
    }

    def process(record: String): Unit = {
      // Write string to connection
    }

    def close(errorOrNull: Throwable): Unit = {
      // Close the connection
    }
  }
).start()

streamingDatasetOfString.writeStream().foreach(
  new ForeachWriter<String>() {

    @Override public boolean open(long partitionId, long version) {
      // Open connection
    }

    @Override public void process(String record) {
      // Write string to connection
    }

    @Override public void close(Throwable errorOrNull) {
      // Close the connection
    }
  }
).start();

spark = ...  # spark session

# Create a streaming DataFrame
df = spark.readStream \
    .format("rate") \
    .option("rowsPerSecond", 10) \
    .load()

# Write the streaming DataFrame to a table
df.writeStream \
    .option("checkpointLocation", "path/to/checkpoint/dir") \
    .toTable("myTable")

# Check the table result
spark.read.table("myTable").show()

# Transform the source dataset and write to a new table
spark.readStream \
    .table("myTable") \
    .select("value") \
    .writeStream \
    .option("checkpointLocation", "path/to/checkpoint/dir") \
    .format("parquet") \
    .toTable("newTable")

# Check the new table result
spark.read.table("newTable").show()

val spark: SparkSession = ...

// Create a streaming DataFrame
val df = spark.readStream
  .format("rate")
  .option("rowsPerSecond", 10)
  .load()

// Write the streaming DataFrame to a table
df.writeStream
  .option("checkpointLocation", "path/to/checkpoint/dir")
  .toTable("myTable")

// Check the table result
spark.read.table("myTable").show()

// Transform the source dataset and write to a new table
spark.readStream
  .table("myTable")
  .select("value")
  .writeStream
  .option("checkpointLocation", "path/to/checkpoint/dir")
  .format("parquet")
  .toTable("newTable")

// Check the new table result
spark.read.table("newTable").show()

SparkSession spark = ...

// Create a streaming DataFrame
Dataset<Row> df = spark.readStream()
  .format("rate")
  .option("rowsPerSecond", 10)
  .load();

// Write the streaming DataFrame to a table
df.writeStream()
  .option("checkpointLocation", "path/to/checkpoint/dir")
  .toTable("myTable");

// Check the table result
spark.read().table("myTable").show();

// Transform the source dataset and write to a new table
spark.readStream()
  .table("myTable")
  .select("value")
  .writeStream()
  .option("checkpointLocation", "path/to/checkpoint/dir")
  .format("parquet")
  .toTable("newTable");

// Check the new table result
spark.read().table("newTable").show();

# Default trigger (runs micro-batch as soon as it can)
df.writeStream \
  .format("console") \
  .start()

# ProcessingTime trigger with two-seconds micro-batch interval
df.writeStream \
  .format("console") \
  .trigger(processingTime='2 seconds') \
  .start()

# One-time trigger (Deprecated, encouraged to use Available-now trigger)
df.writeStream \
  .format("console") \
  .trigger(once=True) \
  .start()

# Available-now trigger
df.writeStream \
  .format("console") \
  .trigger(availableNow=True) \
  .start()

# Continuous trigger with one-second checkpointing interval
df.writeStream
  .format("console")
  .trigger(continuous='1 second')
  .start()

import org.apache.spark.sql.streaming.Trigger

// Default trigger (runs micro-batch as soon as it can)
df.writeStream
  .format("console")
  .start()

// ProcessingTime trigger with two-seconds micro-batch interval
df.writeStream
  .format("console")
  .trigger(Trigger.ProcessingTime("2 seconds"))
  .start()

// One-time trigger (Deprecated, encouraged to use Available-now trigger)
df.writeStream
  .format("console")
  .trigger(Trigger.Once())
  .start()

// Available-now trigger
df.writeStream
  .format("console")
  .trigger(Trigger.AvailableNow())
  .start()

// Continuous trigger with one-second checkpointing interval
df.writeStream
  .format("console")
  .trigger(Trigger.Continuous("1 second"))
  .start()

import org.apache.spark.sql.streaming.Trigger

// Default trigger (runs micro-batch as soon as it can)
df.writeStream
  .format("console")
  .start();

// ProcessingTime trigger with two-seconds micro-batch interval
df.writeStream
  .format("console")
  .trigger(Trigger.ProcessingTime("2 seconds"))
  .start();

// One-time trigger (Deprecated, encouraged to use Available-now trigger)
df.writeStream
  .format("console")
  .trigger(Trigger.Once())
  .start();

// Available-now trigger
df.writeStream
  .format("console")
  .trigger(Trigger.AvailableNow())
  .start();

// Continuous trigger with one-second checkpointing interval
df.writeStream
  .format("console")
  .trigger(Trigger.Continuous("1 second"))
  .start();

# Default trigger (runs micro-batch as soon as it can)
write.stream(df, "console")

# ProcessingTime trigger with two-seconds micro-batch interval
write.stream(df, "console", trigger.processingTime = "2 seconds")

# One-time trigger
write.stream(df, "console", trigger.once = TRUE)

# Continuous trigger is not yet supported

query = df.writeStream.format("console").start()   # get the query object

query.id()          # get the unique identifier of the running query that persists across restarts from checkpoint data

query.runId()       # get the unique id of this run of the query, which will be generated at every start/restart

query.name()        # get the name of the auto-generated or user-specified name

query.explain()   # print detailed explanations of the query

query.stop()      # stop the query

query.awaitTermination()   # block until query is terminated, with stop() or with error

query.exception()       # the exception if the query has been terminated with error

query.recentProgress  # a list of the most recent progress updates for this query

query.lastProgress    # the most recent progress update of this streaming query

val query = df.writeStream.format("console").start()   // get the query object

query.id          // get the unique identifier of the running query that persists across restarts from checkpoint data

query.runId       // get the unique id of this run of the query, which will be generated at every start/restart

query.name        // get the name of the auto-generated or user-specified name

query.explain()   // print detailed explanations of the query

query.stop()      // stop the query

query.awaitTermination()   // block until query is terminated, with stop() or with error

query.exception       // the exception if the query has been terminated with error

query.recentProgress  // an array of the most recent progress updates for this query

query.lastProgress    // the most recent progress update of this streaming query

StreamingQuery query = df.writeStream().format("console").start();   // get the query object

query.id();          // get the unique identifier of the running query that persists across restarts from checkpoint data

query.runId();       // get the unique id of this run of the query, which will be generated at every start/restart

query.name();        // get the name of the auto-generated or user-specified name

query.explain();   // print detailed explanations of the query

query.stop();      // stop the query

query.awaitTermination();   // block until query is terminated, with stop() or with error

query.exception();       // the exception if the query has been terminated with error

query.recentProgress();  // an array of the most recent progress updates for this query

query.lastProgress();    // the most recent progress update of this streaming query

query <- write.stream(df, "console")  # get the query object

queryName(query)          # get the name of the auto-generated or user-specified name

explain(query)            # print detailed explanations of the query

stopQuery(query)          # stop the query

awaitTermination(query)   # block until query is terminated, with stop() or with error

lastProgress(query)       # the most recent progress update of this streaming query

spark = ...  # spark session

spark.streams.active  # get the list of currently active streaming queries

spark.streams.get(id)  # get a query object by its unique id

spark.streams.awaitAnyTermination()  # block until any one of them terminates

val spark: SparkSession = ...

spark.streams.active    // get the list of currently active streaming queries

spark.streams.get(id)   // get a query object by its unique id

spark.streams.awaitAnyTermination()   // block until any one of them terminates

SparkSession spark = ...

spark.streams().active();    // get the list of currently active streaming queries

spark.streams().get(id);   // get a query object by its unique id

spark.streams().awaitAnyTermination();   // block until any one of them terminates

Not available in R.

query = ...  # a StreamingQuery
print(query.lastProgress)

'''
Will print something like the following.

{u'stateOperators': [], u'eventTime': {u'watermark': u'2016-12-14T18:45:24.873Z'}, u'name': u'MyQuery', u'timestamp': u'2016-12-14T18:45:24.873Z', u'processedRowsPerSecond': 200.0, u'inputRowsPerSecond': 120.0, u'numInputRows': 10, u'sources': [{u'description': u'KafkaSource[Subscribe[topic-0]]', u'endOffset': {u'topic-0': {u'1': 134, u'0': 534, u'3': 21, u'2': 0, u'4': 115}}, u'processedRowsPerSecond': 200.0, u'inputRowsPerSecond': 120.0, u'numInputRows': 10, u'startOffset': {u'topic-0': {u'1': 1, u'0': 1, u'3': 1, u'2': 0, u'4': 1}}}], u'durationMs': {u'getOffset': 2, u'triggerExecution': 3}, u'runId': u'88e2ff94-ede0-45a8-b687-6316fbef529a', u'id': u'ce011fdc-8762-4dcb-84eb-a77333e28109', u'sink': {u'description': u'MemorySink'}}
'''

print(query.status)
'''
Will print something like the following.

{u'message': u'Waiting for data to arrive', u'isTriggerActive': False, u'isDataAvailable': False}
'''

val query: StreamingQuery = ...

println(query.lastProgress)

/* Will print something like the following.

{
  "id" : "ce011fdc-8762-4dcb-84eb-a77333e28109",
  "runId" : "88e2ff94-ede0-45a8-b687-6316fbef529a",
  "name" : "MyQuery",
  "timestamp" : "2016-12-14T18:45:24.873Z",
  "numInputRows" : 10,
  "inputRowsPerSecond" : 120.0,
  "processedRowsPerSecond" : 200.0,
  "durationMs" : {
    "triggerExecution" : 3,
    "getOffset" : 2
  },
  "eventTime" : {
    "watermark" : "2016-12-14T18:45:24.873Z"
  },
  "stateOperators" : [ ],
  "sources" : [ {
    "description" : "KafkaSource[Subscribe[topic-0]]",
    "startOffset" : {
      "topic-0" : {
        "2" : 0,
        "4" : 1,
        "1" : 1,
        "3" : 1,
        "0" : 1
      }
    },
    "endOffset" : {
      "topic-0" : {
        "2" : 0,
        "4" : 115,
        "1" : 134,
        "3" : 21,
        "0" : 534
      }
    },
    "numInputRows" : 10,
    "inputRowsPerSecond" : 120.0,
    "processedRowsPerSecond" : 200.0
  } ],
  "sink" : {
    "description" : "MemorySink"
  }
}
*/


println(query.status)

/*  Will print something like the following.
{
  "message" : "Waiting for data to arrive",
  "isDataAvailable" : false,
  "isTriggerActive" : false
}
*/

StreamingQuery query = ...

System.out.println(query.lastProgress());
/* Will print something like the following.

{
  "id" : "ce011fdc-8762-4dcb-84eb-a77333e28109",
  "runId" : "88e2ff94-ede0-45a8-b687-6316fbef529a",
  "name" : "MyQuery",
  "timestamp" : "2016-12-14T18:45:24.873Z",
  "numInputRows" : 10,
  "inputRowsPerSecond" : 120.0,
  "processedRowsPerSecond" : 200.0,
  "durationMs" : {
    "triggerExecution" : 3,
    "getOffset" : 2
  },
  "eventTime" : {
    "watermark" : "2016-12-14T18:45:24.873Z"
  },
  "stateOperators" : [ ],
  "sources" : [ {
    "description" : "KafkaSource[Subscribe[topic-0]]",
    "startOffset" : {
      "topic-0" : {
        "2" : 0,
        "4" : 1,
        "1" : 1,
        "3" : 1,
        "0" : 1
      }
    },
    "endOffset" : {
      "topic-0" : {
        "2" : 0,
        "4" : 115,
        "1" : 134,
        "3" : 21,
        "0" : 534
      }
    },
    "numInputRows" : 10,
    "inputRowsPerSecond" : 120.0,
    "processedRowsPerSecond" : 200.0
  } ],
  "sink" : {
    "description" : "MemorySink"
  }
}
*/


System.out.println(query.status());
/*  Will print something like the following.
{
  "message" : "Waiting for data to arrive",
  "isDataAvailable" : false,
  "isTriggerActive" : false
}
*/

query <- ...  # a StreamingQuery
lastProgress(query)

'''
Will print something like the following.

{
  "id" : "8c57e1ec-94b5-4c99-b100-f694162df0b9",
  "runId" : "ae505c5a-a64e-4896-8c28-c7cbaf926f16",
  "name" : null,
  "timestamp" : "2017-04-26T08:27:28.835Z",
  "numInputRows" : 0,
  "inputRowsPerSecond" : 0.0,
  "processedRowsPerSecond" : 0.0,
  "durationMs" : {
    "getOffset" : 0,
    "triggerExecution" : 1
  },
  "stateOperators" : [ {
    "numRowsTotal" : 4,
    "numRowsUpdated" : 0
  } ],
  "sources" : [ {
    "description" : "TextSocketSource[host: localhost, port: 9999]",
    "startOffset" : 1,
    "endOffset" : 1,
    "numInputRows" : 0,
    "inputRowsPerSecond" : 0.0,
    "processedRowsPerSecond" : 0.0
  } ],
  "sink" : {
    "description" : "org.apache.spark.sql.execution.streaming.ConsoleSink@76b37531"
  }
}
'''

status(query)
'''
Will print something like the following.

{
  "message" : "Waiting for data to arrive",
  "isDataAvailable" : false,
  "isTriggerActive" : false
}
'''

spark = ...

class Listener(StreamingQueryListener):
    def onQueryStarted(self, event):
        print("Query started: " + queryStarted.id)

    def onQueryProgress(self, event):
        print("Query made progress: " + queryProgress.progress)

    def onQueryTerminated(self, event):
        print("Query terminated: " + queryTerminated.id)


spark.streams.addListener(Listener())

val spark: SparkSession = ...

spark.streams.addListener(new StreamingQueryListener() {
    override def onQueryStarted(queryStarted: QueryStartedEvent): Unit = {
        println("Query started: " + queryStarted.id)
    }
    override def onQueryTerminated(queryTerminated: QueryTerminatedEvent): Unit = {
        println("Query terminated: " + queryTerminated.id)
    }
    override def onQueryProgress(queryProgress: QueryProgressEvent): Unit = {
        println("Query made progress: " + queryProgress.progress)
    }
})

SparkSession spark = ...

spark.streams().addListener(new StreamingQueryListener() {
    @Override
    public void onQueryStarted(QueryStartedEvent queryStarted) {
        System.out.println("Query started: " + queryStarted.id());
    }
    @Override
    public void onQueryTerminated(QueryTerminatedEvent queryTerminated) {
        System.out.println("Query terminated: " + queryTerminated.id());
    }
    @Override
    public void onQueryProgress(QueryProgressEvent queryProgress) {
        System.out.println("Query made progress: " + queryProgress.progress());
    }
});

Not available in R.

spark.conf.set("spark.sql.streaming.metricsEnabled", "true")
# or
spark.sql("SET spark.sql.streaming.metricsEnabled=true")

spark.conf.set("spark.sql.streaming.metricsEnabled", "true")
// or
spark.sql("SET spark.sql.streaming.metricsEnabled=true")

spark.conf().set("spark.sql.streaming.metricsEnabled", "true");
// or
spark.sql("SET spark.sql.streaming.metricsEnabled=true");

sql("SET spark.sql.streaming.metricsEnabled=true")

aggDF \
    .writeStream \
    .outputMode("complete") \
    .option("checkpointLocation", "path/to/HDFS/dir") \
    .format("memory") \
    .start()

aggDF
  .writeStream
  .outputMode("complete")
  .option("checkpointLocation", "path/to/HDFS/dir")
  .format("memory")
  .start()

aggDF
  .writeStream()
  .outputMode("complete")
  .option("checkpointLocation", "path/to/HDFS/dir")
  .format("memory")
  .start();

write.stream(aggDF, "memory", outputMode = "complete", checkpointLocation = "path/to/HDFS/dir")