public void setJoinRemovalSemiJoin(int dimIdx, LogicalJoin semiJoin) {
    joinRemovalSemiJoins[dimIdx] = semiJoin;
  }
Indicates the semi-join that allows the join of a dimension table to be
removed.

@param dimIdx Dimension factor
@param semiJoin the semijoin
ql/src/java/org/apache/hadoop/hive/ql/optimizer/calcite/rules/HiveLoptMultiJoin.java