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org.apache.spark.sql.streaming

DataStreamWriter

abstract class DataStreamWriter[T] extends WriteConfigMethods[DataStreamWriter[T]]

Interface used to write a streaming Dataset to external storage systems (e.g. file systems, key-value stores, etc). Use Dataset.writeStream to access this.

Annotations
@Evolving()
Source
DataStreamWriter.scala
Since

2.0.0

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  1. DataStreamWriter
  2. WriteConfigMethods
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Visibility
  1. Public
  2. Protected

Instance Constructors

  1. new DataStreamWriter()

Abstract Value Members

  1. abstract def clusterBy(colNames: String*): DataStreamWriter.this.type

    Clusters the output by the given columns.

    Clusters the output by the given columns. If specified, the output is laid out such that records with similar values on the clustering column are grouped together in the same file.

    Clustering improves query efficiency by allowing queries with predicates on the clustering columns to skip unnecessary data. Unlike partitioning, clustering can be used on very high cardinality columns.

    Annotations
    @varargs()
    Since

    4.0.0

  2. abstract def foreach(writer: ForeachWriter[T]): DataStreamWriter.this.type

    Sets the output of the streaming query to be processed using the provided writer object.

    Sets the output of the streaming query to be processed using the provided writer object. object. See org.apache.spark.sql.ForeachWriter for more details on the lifecycle and semantics.

    Since

    2.0.0

  3. abstract def foreachBatch(function: (Dataset[T], Long) => Unit): DataStreamWriter.this.type

    :: Experimental ::

    :: Experimental ::

    (Scala-specific) Sets the output of the streaming query to be processed using the provided function. This is supported only in the micro-batch execution modes (that is, when the trigger is not continuous). In every micro-batch, the provided function will be called in every micro-batch with (i) the output rows as a Dataset and (ii) the batch identifier. The batchId can be used to deduplicate and transactionally write the output (that is, the provided Dataset) to external systems. The output Dataset is guaranteed to be exactly the same for the same batchId (assuming all operations are deterministic in the query).

    Annotations
    @Evolving()
    Since

    2.4.0

  4. abstract def format(source: String): DataStreamWriter.this.type

    Specifies the underlying output data source.

    Specifies the underlying output data source.

    Since

    2.0.0

  5. abstract def option(key: String, value: String): DataStreamWriter[T]

    Add a write option.

    Add a write option.

    Definition Classes
    WriteConfigMethods
    Since

    3.0.0

  6. abstract def options(options: Map[String, String]): DataStreamWriter[T]

    Add write options from a Java Map.

    Add write options from a Java Map.

    Definition Classes
    WriteConfigMethods
    Since

    3.0.0

  7. abstract def options(options: Map[String, String]): DataStreamWriter[T]

    Add write options from a Scala Map.

    Add write options from a Scala Map.

    Definition Classes
    WriteConfigMethods
    Since

    3.0.0

  8. abstract def outputMode(outputMode: String): DataStreamWriter.this.type

    Specifies how data of a streaming DataFrame/Dataset is written to a streaming sink.

    Specifies how data of a streaming DataFrame/Dataset is written to a streaming sink. - append: only the new rows in the streaming DataFrame/Dataset will be written to the sink.

    • complete: all the rows in the streaming DataFrame/Dataset will be written to the sink every time there are some updates.
    • update: only the rows that were updated in the streaming DataFrame/Dataset will be written to the sink every time there are some updates. If the query doesn't contain aggregations, it will be equivalent to append mode.
    Since

    2.0.0

  9. abstract def outputMode(outputMode: OutputMode): DataStreamWriter.this.type

    Specifies how data of a streaming DataFrame/Dataset is written to a streaming sink.

    Specifies how data of a streaming DataFrame/Dataset is written to a streaming sink. - OutputMode.Append(): only the new rows in the streaming DataFrame/Dataset will be written to the sink.

    • OutputMode.Complete(): all the rows in the streaming DataFrame/Dataset will be written to the sink every time there are some updates. - OutputMode.Update(): only the rows that were updated in the streaming DataFrame/Dataset will be written to the sink every time there are some updates. If the query doesn't contain aggregations, it will be equivalent to OutputMode.Append() mode.
    Since

    2.0.0

  10. abstract def partitionBy(colNames: String*): DataStreamWriter.this.type

    Partitions the output by the given columns on the file system.

    Partitions the output by the given columns on the file system. If specified, the output is laid out on the file system similar to Hive's partitioning scheme. As an example, when we partition a dataset by year and then month, the directory layout would look like:

    • year=2016/month=01/
    • year=2016/month=02/

    Partitioning is one of the most widely used techniques to optimize physical data layout. It provides a coarse-grained index for skipping unnecessary data reads when queries have predicates on the partitioned columns. In order for partitioning to work well, the number of distinct values in each column should typically be less than tens of thousands.

    Annotations
    @varargs()
    Since

    2.0.0

  11. abstract def queryName(queryName: String): DataStreamWriter.this.type

    Specifies the name of the org.apache.spark.sql.streaming.StreamingQuery that can be started with start().

    Specifies the name of the org.apache.spark.sql.streaming.StreamingQuery that can be started with start(). This name must be unique among all the currently active queries in the associated SparkSession.

    Since

    2.0.0

  12. abstract def start(): StreamingQuery

    Starts the execution of the streaming query, which will continually output results to the given path as new data arrives.

    Starts the execution of the streaming query, which will continually output results to the given path as new data arrives. The returned org.apache.spark.sql.streaming.StreamingQuery object can be used to interact with the stream. Throws a TimeoutException if the following conditions are met:

    • Another run of the same streaming query, that is a streaming query sharing the same checkpoint location, is already active on the same Spark Driver
    • The SQL configuration spark.sql.streaming.stopActiveRunOnRestart is enabled
    • The active run cannot be stopped within the timeout controlled by the SQL configuration spark.sql.streaming.stopTimeout
    Annotations
    @throws(scala.this.throws.<init>$default$1[java.util.concurrent.TimeoutException])
    Since

    2.0.0

  13. abstract def start(path: String): StreamingQuery

    Starts the execution of the streaming query, which will continually output results to the given path as new data arrives.

    Starts the execution of the streaming query, which will continually output results to the given path as new data arrives. The returned org.apache.spark.sql.streaming.StreamingQuery object can be used to interact with the stream.

    Since

    2.0.0

  14. abstract def toTable(tableName: String): StreamingQuery

    Starts the execution of the streaming query, which will continually output results to the given table as new data arrives.

    Starts the execution of the streaming query, which will continually output results to the given table as new data arrives. The returned org.apache.spark.sql.streaming.StreamingQuery object can be used to interact with the stream.

    For v1 table, partitioning columns provided by partitionBy will be respected no matter the table exists or not. A new table will be created if the table not exists.

    For v2 table, partitionBy will be ignored if the table already exists. partitionBy will be respected only if the v2 table does not exist. Besides, the v2 table created by this API lacks some functionalities (e.g., customized properties, options, and serde info). If you need them, please create the v2 table manually before the execution to avoid creating a table with incomplete information.

    Annotations
    @Evolving() @throws(scala.this.throws.<init>$default$1[java.util.concurrent.TimeoutException])
    Since

    3.1.0

  15. abstract def trigger(trigger: Trigger): DataStreamWriter.this.type

    Set the trigger for the stream query.

    Set the trigger for the stream query. The default value is ProcessingTime(0) and it will run the query as fast as possible.

    Scala Example:

    df.writeStream.trigger(ProcessingTime("10 seconds"))
    
    import scala.concurrent.duration._
    df.writeStream.trigger(ProcessingTime(10.seconds))

    Java Example:

    df.writeStream().trigger(ProcessingTime.create("10 seconds"))
    
    import java.util.concurrent.TimeUnit
    df.writeStream().trigger(ProcessingTime.create(10, TimeUnit.SECONDS))
    Since

    2.0.0

Concrete Value Members

  1. final def !=(arg0: Any): Boolean
    Definition Classes
    AnyRef → Any
  2. final def ##: Int
    Definition Classes
    AnyRef → Any
  3. final def ==(arg0: Any): Boolean
    Definition Classes
    AnyRef → Any
  4. final def asInstanceOf[T0]: T0
    Definition Classes
    Any
  5. def clone(): AnyRef
    Attributes
    protected[lang]
    Definition Classes
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    Annotations
    @throws(classOf[java.lang.CloneNotSupportedException]) @IntrinsicCandidate() @native()
  6. final def eq(arg0: AnyRef): Boolean
    Definition Classes
    AnyRef
  7. def equals(arg0: AnyRef): Boolean
    Definition Classes
    AnyRef → Any
  8. def foreachBatch(function: VoidFunction2[Dataset[T], Long]): DataStreamWriter.this.type

    :: Experimental ::

    :: Experimental ::

    (Java-specific) Sets the output of the streaming query to be processed using the provided function. This is supported only in the micro-batch execution modes (that is, when the trigger is not continuous). In every micro-batch, the provided function will be called in every micro-batch with (i) the output rows as a Dataset and (ii) the batch identifier. The batchId can be used to deduplicate and transactionally write the output (that is, the provided Dataset) to external systems. The output Dataset is guaranteed to be exactly the same for the same batchId (assuming all operations are deterministic in the query).

    Annotations
    @Evolving()
    Since

    2.4.0

  9. final def getClass(): Class[_ <: AnyRef]
    Definition Classes
    AnyRef → Any
    Annotations
    @IntrinsicCandidate() @native()
  10. def hashCode(): Int
    Definition Classes
    AnyRef → Any
    Annotations
    @IntrinsicCandidate() @native()
  11. final def isInstanceOf[T0]: Boolean
    Definition Classes
    Any
  12. final def ne(arg0: AnyRef): Boolean
    Definition Classes
    AnyRef
  13. final def notify(): Unit
    Definition Classes
    AnyRef
    Annotations
    @IntrinsicCandidate() @native()
  14. final def notifyAll(): Unit
    Definition Classes
    AnyRef
    Annotations
    @IntrinsicCandidate() @native()
  15. def option(key: String, value: Double): DataStreamWriter.this.type

    Add a double output option.

    Add a double output option.

    Definition Classes
    DataStreamWriterWriteConfigMethods
    Since

    3.0.0

  16. def option(key: String, value: Long): DataStreamWriter.this.type

    Add a long output option.

    Add a long output option.

    Definition Classes
    DataStreamWriterWriteConfigMethods
    Since

    3.0.0

  17. def option(key: String, value: Boolean): DataStreamWriter.this.type

    Add a boolean output option.

    Add a boolean output option.

    Definition Classes
    DataStreamWriterWriteConfigMethods
    Since

    3.0.0

  18. final def synchronized[T0](arg0: => T0): T0
    Definition Classes
    AnyRef
  19. def toString(): String
    Definition Classes
    AnyRef → Any
  20. final def wait(arg0: Long, arg1: Int): Unit
    Definition Classes
    AnyRef
    Annotations
    @throws(classOf[java.lang.InterruptedException])
  21. final def wait(arg0: Long): Unit
    Definition Classes
    AnyRef
    Annotations
    @throws(classOf[java.lang.InterruptedException]) @native()
  22. final def wait(): Unit
    Definition Classes
    AnyRef
    Annotations
    @throws(classOf[java.lang.InterruptedException])

Deprecated Value Members

  1. def finalize(): Unit
    Attributes
    protected[lang]
    Definition Classes
    AnyRef
    Annotations
    @throws(classOf[java.lang.Throwable]) @Deprecated
    Deprecated

    (Since version 9)

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