private VectorizationCondition[] createMergeWorkExplainVectorizationConditions() {

      boolean enabled = false;

      VectorizationCondition[] conditions = new VectorizationCondition[] {
          new VectorizationCondition(
              enabled,
              "Vectorizing MergeJoin Supported")
      };
      return conditions;
    }
For now, this class just says in EXPLAIN VECTORIZATION we don't support vectorization of the
Merge Join vertex instead of being silent about it.
ql/src/java/org/apache/hadoop/hive/ql/plan/MergeJoinWork.java