This morning, I planned to refresh one of my development databases using a database restore. In order to restrict access to the database as I start the restore, I use ALTER DATABASE to set the database to single_user mode, specifying the ROLLBACK IMMEDIATE option. This typically works fine.
When I ran it this morning, I noticed that the alter was taking a long time. When I ran sp_who2, it showed my spid blocked by -2 and in a suspended status. I thought this might be due to a large rollback, but DBCC OPENTRAN showed no open transactions in this database.
Does anybody have any thoughts on why I was being blocked and put into a suspended status? Thanks in advance for your help.