As far as i noticed, there isn't an DirectoryProvider implementation for storing indexes in database.

Lucene has this possibility. I wonder if i can use that as fallback.

Thanks,
Florin marcus

Lucene does not have that capability. There is some implementations out there for a DBDirectory, but they usually don't scale very well:
- remote IO to read the index
- usually build on blobs
- updating an index lock in Lucene

If you are only looking for the ability to share index across several machines, check the JMS clustering solution of Hibernate Search. Even if you don't use JMs per se, you can use the Master and Slave FSDirectoryProvider that will do the copy for you.

Thanks a lot, emmanuel.
Since I have a clustering solution, there is no reason to stick with the database index storing idea.