我尝试使用hive udf udfrowsequence生成自动增量值，但是它为前两个记录生成相同的id。

+-------+----------+---+-------------------+
|rank_id|     state| id|           datetime|
+-------+----------+---+-------------------+
|      1|New Jersey| 10|2018-03-27 10:00:00|
|      1|     Tamil| 25|2018-03-27 11:05:00|
|      2|   TamilNa| 25|2018-03-27 11:15:00|
|      3| TamilNadu| 25|2018-03-27 11:25:00|
|      4|   Gujarat| 30|2018-03-27 11:00:00|
+-------+----------+---+-------------------+

下面是我用于自动递增的代码。

package org.apache.hadoop.hive.contrib.udf;

import org.apache.hadoop.hive.ql.exec.Description;
import org.apache.hadoop.hive.ql.exec.UDF;
import org.apache.hadoop.hive.ql.udf.UDFType;
import org.apache.hadoop.io.LongWritable;

/**
 * UDFRowSequence.
 */
@Description(name = "row_sequence",
    value = "_FUNC_() - Returns a generated row sequence number starting from 1")
@UDFType(deterministic = false, stateful = true)
public class UDFRowSequence extends UDF
{
  private LongWritable result = new LongWritable();

  public UDFRowSequence() {
    result.set(0);
  }

  public LongWritable evaluate() {
    result.set(result.get() + 1);
    return result;
  }
}

有谁能告诉我，我做了什么不对，这是产生相同的id为前两个记录。