hadoop 计算 pv uv

java.lang.OutOfMemoryError: Java heap space

public void reduce(TextPair key, Iterable<Text> values, Context context)
 throws IOException, InterruptedException {
  Iterator<Text> it = values.iterator();

  Long pv_wap =0L;
  Long uv_wap=0L;
 
  String tempvalue="";
  String cookie_id="";
  String last_wap_cookie="";
  while (it.hasNext()) {
   it.next();
   cookie_id = key.getSecond().toString();
    pv_wap++;
    if(!cookie_id.equals(last_wap_cookie)){
     uv_wap++;
     last_wap_cookie=cookie_id;
    }
    }