The question is, if you’re a DBA, how to you make sense of all the Cumulative Updates (CUs which contain critical on demand updates from clients), Service Packs (SP), Security Updates (SU), General Distribution Releases (GDR), and the acronym I have only noticed recently - QFE (most have heard of hotfixes, but this particular one means a Quck Fix [from] Engineering) updates. This is where this explanation of Microsoft`s Incremental Servicing Model from the SQL Server Team steps in to help, in fact, after 15 years of administering SQL Server, I have not found a page with such an updated description of how SQL is patched, and this is thanks to a recent visit from Felix Avemore, a Microsoft SQL Server Premier Field Engineer based in Quebec City.
For Microsoft Premier Field Engineers for SQL Server, it’s clear, your priority is to apply important Security Updates before anything else, but often those updates require the application of a CU or an SP as a pre-requisite, which makes patching a painful affair when you have the daunting task of updating 3-400 servers! That is where updated/clear documentation, system backups, and checklists come in rather handy, and perhaps deeper recommendations from the vendor to validate registry keys if your system is in production and ultra-sensitive. If ever you arrive with a corrupt master, attempt restore but always remember you can rebuild the instance cleanly with the exact Configuration.ini file found within the setup bootstrap folder (please see a previous post on command line installs for more).
therefore for 2008-2014, here’s a quick guide:
SQL Server Version
General Distribution Release (GDR)
Quick Fix [from] Engineering (QFE)
SP1 (without any CUs)
CU1 - CU2
There are clear arguments, as laid out well by Glenn Berry here, that you should apply recent Cumulative Updates to maintain proper performance, stability, and regular maintenance of your SQL Server Instances.
Are QFEs cumulative? By their build level, it would appear so, and after reading several definitions, I can confirm that they are indeed cumulative hotfixes also.
Hope this clears up some of the muddy pathway you`ll find attempting to keep up with patches on SQL Server.
The above post was mentioned in the DatabaseWeekly.com E-mail Newletter for September 1st,2014.