title: Solr DataImportHandler delta import
body: <p>I am using DataImportHandler for indexing data in SOLR. I used full-import to index all the data in the my database which is around 10000 products.Now I am confused with the delta-import usage? Does it index the new data added into the database on interval basis i mean it is going to index the new data added to my table around 10 rows or it just updates the changes in the already indexed data. </p>
  
  <p>Can anyone please explain it to me with simple example as soon as you can.</p>