@Override
  public String vectorExpressionParameters() {
    DecimalTypeInfo decimalTypeInfo = (DecimalTypeInfo) inputTypeInfos[1];
    HiveDecimalWritable writable = new HiveDecimalWritable();
    writable.deserialize64(arg2Scalar, decimalTypeInfo.scale());
    return
        getColumnParamString(0, inputColumnNum[0]) +
        ", decimal64Val " + arg2Scalar + ", decimalVal " + writable.toString() +
        ", " + getColumnParamString(1, inputColumnNum[1]);
  }
Compute IF(expr1, expr2, expr3) for 3 input column expressions.
The first is always a boolean (LongColumnVector).
The second is a column or non-constant expression result.
The third is a constant value.
ql/src/java/org/apache/hadoop/hive/ql/exec/vector/expressions/IfExprDecimal64ScalarDecimal64Column.java