// Start spark-shell with broadcast hash join disabled, i.e. spark.sql.autoBroadcastJoinThreshold=-1
// ./bin/spark-shell -c spark.sql.autoBroadcastJoinThreshold=-1
// Mind the data types so ShuffledHashJoinExec is not selected
val dataset = Seq(
  (0, "playing"),
  (1, "with"),
  (2, "SortMergeJoinExec")
).toDF("id", "token")

// all data types are orderable
scala> dataset.printSchema
root
 |-- id: integer (nullable = false)
 |-- token: string (nullable = true)

scala> spark.conf.get("spark.sql.autoBroadcastJoinThreshold")
res0: String = -1

val q = dataset.join(tokens, Seq("id"), "inner")
scala> q.explain
== Physical Plan ==
*Project [id#27, token#28, token#6]
+- *SortMergeJoin [id#27], [id#5], Inner
   :- *Sort [id#27 ASC NULLS FIRST], false, 0
   :  +- Exchange hashpartitioning(id#27, 200)
   :     +- LocalTableScan [id#27, token#28]
   +- *Sort [id#5 ASC NULLS FIRST], false, 0
      +- ReusedExchange [id#5, token#6], Exchange hashpartitioning(id#27, 200)

scala> q.queryExecution.debug.codegen
Found 3 WholeStageCodegen subtrees.
== Subtree 1 / 3 ==
*Project [id#5, token#6, token#11]
+- *SortMergeJoin [id#5], [id#10], Inner
   :- *Sort [id#5 ASC NULLS FIRST], false, 0
   :  +- Exchange hashpartitioning(id#5, 200)
   :     +- LocalTableScan [id#5, token#6]
   +- *Sort [id#10 ASC NULLS FIRST], false, 0
      +- ReusedExchange [id#10, token#11], Exchange hashpartitioning(id#5, 200)

Generated code:
/* 001 */ public Object generate(Object[] references) {
/* 002 */   return new GeneratedIterator(references);
/* 003 */ }
/* 004 */
/* 005 */ final class GeneratedIterator extends org.apache.spark.sql.execution.BufferedRowIterator {
/* 006 */   private Object[] references;
/* 007 */   private scala.collection.Iterator[] inputs;
/* 008 */   private scala.collection.Iterator smj_leftInput;
/* 009 */   private scala.collection.Iterator smj_rightInput;
/* 010 */   private InternalRow smj_leftRow;
/* 011 */   private InternalRow smj_rightRow;
/* 012 */   private int smj_value2;
/* 013 */   private org.apache.spark.sql.execution.ExternalAppendOnlyUnsafeRowArray smj_matches;
/* 014 */   private int smj_value3;
/* 015 */   private int smj_value4;
/* 016 */   private UTF8String smj_value5;
/* 017 */   private boolean smj_isNull2;
/* 018 */   private org.apache.spark.sql.execution.metric.SQLMetric smj_numOutputRows;
/* 019 */   private UnsafeRow smj_result;
/* 020 */   private org.apache.spark.sql.catalyst.expressions.codegen.BufferHolder smj_holder;
/* 021 */   private org.apache.spark.sql.catalyst.expressions.codegen.UnsafeRowWriter smj_rowWriter;
...