MyBatis multi-datasource configuration issue

Using mybatis 3.2.8 ,Spring 3.2.9 release,mybatis-spring 1.2.2 to configure my project's DAO and the project need to convenient both mysql and oracle so i use the databaseIdProvider to adapt multi-datasource here is my configuration:

1. datasource

<bean id="dataSource" class="org.springframework.jndi.JndiObjectFactoryBean">
  <property name="jndiName">
    <value>xxxxx</value>
  </property>
</bean>

2. vendorProperties

<bean id="vendorProperties" class="org.springframework.beans.factory.config.PropertiesFactoryBean">
  <property name="properties">
    <props>
      <prop key="SQL Server">sqlserver</prop>
      <prop key="DB2">db2</prop>
      <prop key="Oracle">oracle</prop>
      <prop key="MySQL">mysql</prop>
      <prop key="H2">h2</prop>
    </props>
  </property>
</bean>

3. databaseIdProvider

<bean id="databaseIdProvider" class="org.apache.ibatis.mapping.VendorDatabaseIdProvider">
  <property name="properties" ref="vendorProperties" />
</bean>

4. sqlSessionFactory

<bean id="sqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean">
  <property name="dataSource" ref="dataSource" />
  <property name="databaseIdProvider" ref="databaseIdProvider" />
  <property name="configLocation" value="classpath:mybatis-config.xml"></property>
</bean>

because mysql's paging is different from oracle's so i wrote two ways of paging and depends on runtime environment to chose to use which.here is the mapper.xml:

<sql databaseId="oracle" id="PagePrefix">
  <!--
          WARNING - @mbggenerated
          This element is automatically generated by MyBatis Generator, do not modify.
        -->
  <if test="page != null">
    select * from ( select row_.*, rownum rownum_ from (
  </if>
</sql>
<sql databaseId="mysql" id="PagePrefix">
  <!--
          WARNING - @mbggenerated
          This element is automatically generated by MyBatis Generator, do not modify.
        -->
  <if test="page != null">
    select * from (
  </if>
</sql>

and use it like this:

<select id="selectByExample" parameterType="xxx.xxx.xxx" resultMap="BaseResultMap">
  <!--
          WARNING - @mbggenerated
          This element is automatically generated by MyBatis Generator, do not modify.
        -->
  <include refid="PagePrefix" />select
  <if test="distinct">
    distinct
  </if>
  from xxx
  <if test="_parameter != null">
    <include refid="Example_Where_Clause" />
  </if>
  <include refid="PageSuffix" />
</select>

the above is all my configuration. when i am running the query operation or any other DML,the console will print:

org.apache.ibatis.builder.IncompleteElementException: Could not find SQL statement to include with refid 'xxx.xxx.xxx.PagePrefix'

i find this exception was caused by org.apache.ibatis.session.Configuration.sqlFragments did not had the value that the key is 'PagePrefix'. so i following the blow steps to find what is wrong:

1. my local environment is oracle,so i modified the mapper.xml, removed the mysql config just left the oracle config:

<sql databaseId="oracle" id="PagePrefix">
  <!--
              WARNING - @mbggenerated
              This element is automatically generated by MyBatis Generator, do not modify.
            -->
  <if test="page != null">
    select * from ( select row_.*, rownum rownum_ from (
  </if>
</sql>

but it's also not work,the exception still remained.

2. then i thought maybe the mybatis did not recognized my runtime environment,so i looked into the source code to find out the whether the information was set into the mybatis or not.i find the startup class org.mybatis.spring.SqlSessionFactoryBean#buildSqlSessionFactory() method has:

    if (this.databaseIdProvider != null) {
          try {
            configuration.setDatabaseId(this.databaseIdProvider.getDatabaseId(this.dataSource));
          } catch (SQLException e) {
            throw new NestedIOException("Failed getting a databaseId", e);
          }
        }

and i toggled breakpoint in here and find the value was right.

3. Then i started to find where and when the sqlFragments was assigned value.i found that sqlFragments was assigned when parsing the mapper.xml: org.apache.ibatis.builder.xml.XMLMapperBuilder#configurationElement()

     private void configurationElement(XNode context) {
        try {
          String namespace = context.getStringAttribute("namespace");
          if (namespace.equals("")) {
                  throw new BuilderException("Mapper's namespace cannot be empty");
          }
          builderAssistant.setCurrentNamespace(namespace);
          cacheRefElement(context.evalNode("cache-ref"));
          cacheElement(context.evalNode("cache"));
          parameterMapElement(context.evalNodes("/mapper/parameterMap"));
          resultMapElements(context.evalNodes("/mapper/resultMap"));
          sqlElement(context.evalNodes("/mapper/sql"));
          buildStatementFromContext(context.evalNodes("select|insert|update|delete"));
        } catch (Exception e) {
          throw new BuilderException("Error parsing Mapper XML. Cause: " + e, e);
        }
      }

and the method sqlElement do the actual assign value on sqlFragments and according the databaseId to find the tag ''

    private void sqlElement(List<XNode> list, String requiredDatabaseId) throws Exception {
        for (XNode context : list) {
          String databaseId = context.getStringAttribute("databaseId");
          String id = context.getStringAttribute("id");
          id = builderAssistant.applyCurrentNamespace(id, false);
          if (databaseIdMatchesCurrent(id, databaseId, requiredDatabaseId)) sqlFragments.put(id, context);
        }
      }

but in that time the databaseId hasn't been set yet beacuse the parsing phase is before the setDatabaseId operation what i mentioned before. Now i have no idea how to solve this problem.does any people encountered the same situation like me?