title: DBMS_MVIEW.REFRESH call cause ORA-01422 error
body: <p>I performed full database import into existing database with identical structure.
  After this, call the DBMS_MVIEW.REFRESH procedure cause ORA-01422 error.
  For example: </p>
  
  <pre><code>begin
   DBMS_MVIEW.REFRESH('SCHEMA_NAME.T_TOP_FRESH_COMMENTS');
  end;
  </code></pre>
  
  <p>Error:
    ORA-01422 exact fetch returns more than requested number of rows<br/>
    ORA-06512: at "SYS.DBMS_SNAPSHOT", line 2563<br/>
    ORA-06512: at "SYS.DBMS_SNAPSHOT", line 2776<br/>
    ORA-06512: at "SYS.DBMS_SNAPSHOT", line 2745<br/>
    ORA-06512: at line 2<br/></p>
  
  <p>Select bellow returns single row:</p>
  
  <pre><code>select * from dba_registered_mviews t where t.name = 'T_TOP_FRESH_COMMENTS'
  </code></pre>
  
  <p>What do errors cause? How can I fix that?
  Thanks!</p>
  
  <p>UPD:<br/>
  Materialized view select doesn’t cause error. The same error repeated for others materialized views.
  Script for creating view is listed below:</p>
  
  <pre><code>CREATE MATERIALIZED VIEW T_TOP_FRESH_COMMENTS
  REFRESH FORCE ON DEMAND
  AS
  SELECT ROWNUM AS order_comment, id_comment, date_refresh
    FROM (  SELECT c.id_comment, MAX (h.updated) date_refresh
                 FROM    t_comment_user c
                   INNER JOIN t_comment_history h  ON c.id_comment = h.id_comment
             WHERE c.published = 'T' AND h.published = 'T' and h.updated is not null GROUP BY c.id_comment
          ORDER BY date_refresh DESC)
   WHERE ROWNUM &lt;= 10;
  </code></pre>
  
  <p>UPD1:
  I ran completed refresh and recieved the same error:</p>
  
  <pre><code>begin
    DBMS_MVIEW.REFRESH('SCHEMA_NAME.T_TOP_FRESH_COMMENTS','c');
  end;
  </code></pre>
  
  <p>I recreated materialized view with REFRESH COMPLETE and this didn't help too.
  I tried to purge view log. It is didn't help:</p>
  
  <pre><code>begin
  dbms_mview.purge_log('SCHEMA_NAME.T_COMMENT_HISTORY',99999,'delete');
  end;
  </code></pre>