Rebuild the Fulltext catalog I have a Database (80GB) that is able to store attachments. These attachments are full text indexed. For some reasons I had to rebuild the fulltext catalog and this took 30 hours.

Our business users noticed while rebuilding the new catalog as some searches didn't work anymore as expected, but some did.

I was wondering how SQL Server proceeds while rebuilding the fulltext catalog.

Does it delete all index and then start rebuilding it? Or is there some intelligent logic behind it, like delete just a part of it piece-by-piece?
I was wondering how SQL Server proceeds while rebuilding the fulltext catalog.


From BOL : 

When you REBUILD a fulltext catalog, SQL Server rebuilds the entire catalog. When a catalog is rebuilt, the existing catalog is deleted and a new catalog is created in its place. All the tables that have full-text indexing references are associated with the new catalog. Rebuilding resets the full-text metadata in the database system tables.

I would suggest you to look into REORGANIZE depending on the fragment counts as described in my answer for Reorganize full text catalog is offline or online?