Solr delta-import across multiple databases

Question

I have created a Solr Index whose documents are formed from Two databases db1 and db2. I can successfully do a full-import as follows:

    <entity name="ent1" dataSource="db1" query="select ID_DB1 from table1">  
       <field column="ID_DB1" name="ID_DB1"/>  

       <entity name="ent2" dataSource="db2" query="select ID_DB2 from table2 where ID_DB2='${ent1.ID_DB1}'">  
       <field column="ID_DB2" name="ID_DB2"/>  
       </entity>    

    </entity>

But delta import throws NullPointerException.
How to write delta-query, parent-delta-query and delta-import-query for this scenario?
Any help is appreciated!

Answer 1

This is possible to have multiple datasources in Solr DIH. Just check this out. You should specify a datasource per <entity>.