spark-sql-streaming-StreamingRelationExec.adoc

StreamingRelationExec Leaf Physical Operator

StreamingRelationExec is a leaf physical operator (i.e. LeafExecNode) that…​FIXME

StreamingRelationExec is created when StreamingRelationStrategy plans StreamingRelation and StreamingExecutionRelation logical operators.

scala> spark.version
res0: String = 2.3.0-SNAPSHOT

val rates = spark.
  readStream.
  format("rate").
  load

// StreamingRelation logical operator
scala> println(rates.queryExecution.logical.numberedTreeString)
00 StreamingRelation DataSource(org.apache.spark.sql.SparkSession@31ba0af0,rate,List(),None,List(),None,Map(),None), rate, [timestamp#0, value#1L]

// StreamingRelationExec physical operator (shown without "Exec" suffix)
scala> rates.explain
== Physical Plan ==
StreamingRelation rate, [timestamp#0, value#1L]

StreamingRelationExec is not supposed to be executed and is used…​FIXME

Creating StreamingRelationExec Instance

StreamingRelationExec takes the following when created:

• The name of a streaming data source

• Output attributes