public interface StreamingDataWriterFactory
A factory of DataWriter returned by
StreamingWrite.createStreamingWriterFactory(PhysicalWriteInfo), which is responsible for
creating and initializing the actual data writer at executor side.
Note that, the writer factory will be serialized and sent to executors, then the data writer
will be created on executors and do the actual writing. So this interface must be
serializable and DataWriter doesn't need to be.
Returns a data writer to do the actual writing work.
DataWriter<org.apache.spark.sql.catalyst.InternalRow> createWriter(int partitionId,
Returns a data writer to do the actual writing work. Note that, Spark will reuse the same data
object instance when sending data to the data writer, for better performance. Data writers
are responsible for defensive copies if necessary, e.g. copy the data before buffer it in a
If this method fails (by throwing an exception), the corresponding Spark write task would fail
and get retried until hitting the maximum retry times.
partitionId - A unique id of the RDD partition that the returned writer will process.
Usually Spark processes many RDD partitions at the same time,
implementations should use the partition id to distinguish writers for
taskId - The task id returned by TaskContext.taskAttemptId(). Spark may run
multiple tasks for the same partition (due to speculation or task failures,
epochId - A monotonically increasing id for streaming queries that are split in to
discrete periods of execution.