Hibernate version: Hibernate search3.0.0

Name and version of the database you are using: MySql 5

The generated SQL (show_sql=true):

I need to create a batch job that would index all my objects in the database. Looking at building something where I configure the class name and the batch indexes all objects of those classes.

The objects in the database might be in millions which I want to index. I am looking for guidance from people on how to write this job which should be performant and should be able to handle this kind of load.

Is there any project/example already available in the repository which I can use to do this stuff?

yes, it's actually documented.
http://www.hibernate.org/hib_docs/search/reference/en/html_single/#search-batchindex-indexing