I recently came across a problem which I have had a couple of times now which seems to be related to database backups in SQL Server 2005.
I was carrying out a manual backup of a database on the production server which was taking a very long time. During this process I came across another problem which needed solving quickly and I couldn't wait until the backup had finished before trying to resolve the issue which was caused by a report called from one database trying to access data from another. It was raising the following error message:
The server principal "XXXXX" is not able to access the database "XXXX" under the current security context.The solution to this problem is to enable the database that needs to be accessed as Trustworthy with an SQL statement like this:
ALTER DATABASE strategies_jobboard SET TRUSTWORTHY ON
The database owner SID recorded in the master database differs from the database owner SID recorded in database 'XXXX'. You should correct this situation by resetting the owner of database 'XXXX' using the ALTER AUTHORIZATION statement.Now this is an error I have come across before when a database has been created on one server by restoring a backup taken from another server and the database owners differ. To prove that the problem is in fact differing SID's I ran the following two SQL statements.
--To get owner SID recorded in the master database for the current database
SELECT owner_sid FROM sys.databases WHERE database_id=DB_ID()
--To get the owner SID recorded for the current database owner
SELECT sid FROM sys.database_principals WHERE name=N'dbo'
They should return you SID values in the format of a GUID e.g
Now if the two SID's differ which they did in my case it means that you need to reset the database owner so that both values are the same. To do this you can run another ALTER statement and pass in the owner value you want to use e.g
ALTER AUTHORIZATION ON Database::XXXX TO [domain\user]
Once I had run this code the problem was fixed. Now I am pretty sure the issue was down to a combination of the backup running at the same time as the code to change the TRUSTWORTHY statement as I had no errors before that SQL was run and as soon as I had executed it the errors started shooting into my inbox.
However I tried to replicate this problem on a development server by running some backups and executing the same SQL but I couldn't re-create the problem. Maybe there was something else in the mix I was unaware of but I thought I would post the solution to the problem anyway in case others have a similar situation arise.