Rolling upgrade using database mirroring (and a bug in 2008 RTM)

While trawling through the latest 2008 Books Online this morning to answer a question, I noticed a new section that I hadn't seen before, which explains in detail how to perform a rolling upgrade with database mirroring. The link to the MSDN page is and below I've linked to the flowchart from that page.  

Books Online also has a lot of other "how-to" topics around database mirroring – here are some links:

Kevin Cox of the SQLCAT team also just blogged about a customer upgrade from 2005 to 2008 and some of the issues they faced. Btw – if you're not subscribed to their blog, you definitely should be – lots of cool stuff.

And now the bug. In 2008 RTM, if your database contains full-text then mirroring will not work when you perform a rolling upgrade. This is explained in KB 956017 (with a trace-flag workaround) and KB 957816, which points at 2008 RTM CU1 that has the fix in.

Couple of nasty FILESTREAM bugs fixed in 2008 RTM CU1

Cumulative Update 1 for SQL 2008 RTM contains fixes for two nasty FILESTREAM bugs (among a lot of other bug fixes).

The first one concerns restoring a 2008 database from a series of log backups when the database contains FILESTREAM info. It’s possible that a race condition can cause one of the log backups to miss backing up a FILESTREAM file – resulting in a corrupt database after a restore operation. See KB 957809 for more details.

The second bug occurs when a clustered index is rebuilt using ALTER INDEX … REBUILD and the table contains FILESTREAM data. In this case, it’s possible that all the FILESTREAM files are copied, meaning the rebuild operation can take a very long time if there’s lots of large FILESTREAM data values in the table. There’s no need for the FILESTREAM data to be copied during an index rebuild as the FILESTREAM locations and filenames remain the same. See KB 957823 for more details.

You can get the fixes for these in CU1 – see KB 956717 for the download (right at the top of the page) and the list of all other fixes included in the update.

SQL Server 2008 patching has begun – and the PSS blog

Just over a month since SQL Server 2008 went to RTM and the first Cumulative Update (CU1) has been released. Bob Ward, a very good friend of mine, and a Principal Escalation Engineer in the SQL Server Product Support team published a detailed blog post on Friday explaining how to get it and install it.

If you’re not subscribed to the PSS blog, you should be. They post a ton of great info on how things work and how to work around bugs. Bob just blogged again today about how SQL Server 2008 Setup itself can be patched – not a trivial problem to engineer around.

Checkout the PSS blog at