missing stacktrace for jdbc appenders

[Noordeen, Roxy]

Hi,
I am using below configurations. I am getting stack trace for my console
appender, where as staketrace is null in my jdbc appender. 
I am not sure what the issue with jdbc appender is.  All my other fields
are getting logged properly in the oracle database except the stack
trace. I tried both clob and varchar2 fields in oracle to store stack
trace.

Please help.

Log4j.xml 

   <appender name="CONSOLE" class="org.apache.log4j.ConsoleAppender">
      <errorHandler
class="org.jboss.logging.util.OnlyOnceErrorHandler"/>
      <param name="Target" value="System.out"/>
      <layout class="org.apache.log4j.PatternLayout">
         <param name="ConversionPattern" value="%d{ABSOLUTE} %-5p %C -
[%c{1}] - %F %m; %n"/>
      </layout>
   </appender>

    <appender name="jdbcAppender"
class="org.apache.log4j.jdbc.JDBCAppender">
        <param name="Threshold" value="ERROR"/>
        <param name="URL" value="jdbc:oracle:thin:@polaris:1521:dptrx"/>
        <param name="Driver" value="oracle.jdbc.driver.OracleDriver" />
        <param name="User" value="weblogicuser20"/>
        <param name="Password" value="hmi"/>
        <layout class="org.apache.log4j.PatternLayout">
            <param name="ConversionPattern" value="INSERT INTO ERROR_LOG
(TRACKING_ID, LOG_LEVEL, PROCESS_NAME,METHOD_NAME,
USER_ERROR_MSG,SYSTEM_ERROR_MSG,ERROR_DATE) VALUES
(hmi20.TRACKING_ID_SEQ.nextval, '%p', '%C','%M() at line#: %L',
'%m','%m; %n', sysdate)" />
        </layout>
    </appender>