title: Oracle LPAD/RPAD function issue in AL32UTF8
body: <p>The NLS_CHARACTERSET is AL23UTF8 in my Oracle database.
  I have problem when using the RPAD function:</p>
  
  <pre><code>Connected to Oracle Database 11g Enterprise Edition Release 11.2.0.3.0 
  Connected as apps@UATSED
  
  SQL&gt; 
  SQL&gt; SELECT '甲骨文' ORACLE, LENGTHB('甲骨文') ORACLE_LENGTH,
    2         RPAD('甲骨文', 10, '$') ORA_RPAD, LENGTHB(RPAD('甲骨文', 10, '$')) ORA_RPAD_LENGTH
    3    FROM dual
    4  ;
  
  ORACLE    ORACLE_LENGTH ORA_RPAD      ORA_RPAD_LENGTH
  --------- ------------- ------------- ---------------
  甲骨文                9 甲骨文$$$$                 13
  
  SQL&gt; 
  </code></pre>
  
  <p>We know a Chinese character take 3 bytes in AL32UTF8 encoding method.
  Therefore in my example, the lengthb function returns the correct result.
  But we I use RPAD function to pad more spaces with $, it took 2 bytes for one Chinese character, not 3 bytes. So when i pad 10 bytes in total, it filled 4 $ signs for me.</p>
  
  <p>My question is why RPAD function don't follow the way like lengthb?</p>