Every type from cm:content includes a default d:content property to store the content. You can declare additional d:content properties, or “secondary” properties.
Search Services 1.x indexed the content of secondary d:content properties defined for a custom Content Model Type. This feature is unsupported by Search Services 2.x. If your use case depends upon searching for content in the secondary d:content properties, you need to re-design your Content Model before upgrading.
The following sample Content Model describes a secondary d:content property named doc:attachment:
<type name="doc:sample">
<parent>cm:content</parent>
<properties>
<property name="doc:identifier">
<type>d:text</type>
</property>
<property name="doc:attachment">
<type>d:content</type>
</property>
</properties>
</type>
When using Search Services 1.x, the content stored in doc:attachment is indexed and searchable. From Search Services 2.x, the property doc:attachment is indexed but the content is not. So searching by content of the property is not working.
In order to support this Content Model from Search Services 2.x, secondary d:content fields should be converted to associations (either association or child-association) with cm:content nodes. The following sample Content Model applies this conversion to the previous model:
<type name="doc:sample">
<parent>cm:content</parent>
<properties>
<property name="doc:identifier">
<type>d:text</type>
</property>
</properties>
<mandatory-aspects>
<aspect>cm:attachable</aspect>
</mandatory-aspects>
</type>
<aspect name="cm:attachable">
<associations>
<association name="cm:attachments">
<source>
<mandatory>false</mandatory>
<many>true</many>
</source>
<target>
<class>cm:content</class>
<mandatory>false</mandatory>
<many>true</many>
</target>
</association>
</associations>
</aspect>