Sql-server – Ways of estimating the time to perform a database shrink on SQL Server

MS KB 325335 has options on how to do this for the whole db and all columns.

Basically:

1. Script database tables (with new collation)
2. DTS/SSIS data (watching collation)
3. Add constraints

No way to estimate how long it will take - so many different things would have an impact. Similar to what Paul writes about the length of a CHECKDB, very similar things would come into play with indexing and more. The best answer would be how long has it taken in the past? If you can't determine that, next best option would probably be to try it on a similar non-production environment, but even that won't necessarily match (i.e. concurrency concerns, etc. would be different).

As a side note, you may want to look into ONLINE INDEX OPERATIONS in Sql 2005 and above...I can't add a second hyperlink, but google "online index operations sql server" and click the top link.