Microsoft isn’t perfect, so it releases regular updates to SQL Server. They come in a few forms, but the one I see most is the Cumulative Update (CU). Microsoft’s servicing model page gives the schedule for SQL Server 2017 and later. CUs come out every month for the first year after a release, and every two months for the remaining four years of the five-year mainstream lifecycle. A version that has been out for a while is on the two-month schedule, which helps when planning maintenance windows.
Below are the steps to download and install the latest CU on your SQL Server.
Download the Latest CU
The latest CU for each supported version is listed on Microsoft’s release page.
Each cumulative update is specific to a SQL Server version (SQL Server 2019, 2022, and so on), so check which version you’re on first by running this in SSMS:
SELECT @@VERSIONBefore you go looking, check that your version still gets CUs. The servicing page says “CU31 for 2017 is the last CU for SQL Server 2017,” and that Microsoft no longer ships CUs for SQL Server 2016 and earlier, only on-demand fixes and security updates.
From the release page, select your version, and you’ll be taken to the KB page for that CU. Read the documentation for your CU, then scroll down to the section marked How to obtain or download this or the latest cumulative update package and click the link labeled Download the latest cumulative update package for SQL Server 20xx now.
That takes you to one more page, where you download the CU itself. It’s usually an .exe named something like SQLServer20xx-KBxxxxxxx-x64.exe.
Installing the CU
Installing a CU requires downtime for your SQL Server, so get a maintenance window before you start. Make sure you have a recent database backup before installing the CU. It can be the difference between a 15-minute maintenance task and a 3-hour phone call with your boss, sales, and an angry client. Once that’s done, right-click the .exe and choose Run as Administrator to open the SQL Server Update installer.
The installer walks you through a few steps:
- Accept the License Terms: Read through and accept the license agreement.
- Select SQL Server Instances: The installer detects the SQL Server instances on the machine. Choose the ones you want to update.
- File Check: The installer checks that the files it needs aren’t in use. When it finishes, click
Next. - Summary: Review the summary to make sure it’s accurate, and click
Update.
The update takes a few minutes, depending on your system and SQL Server configuration. The selected instances may be unavailable while it runs, so this is when users start calling if they weren’t told about the downtime.
When it finishes, check that every operation shows Successful and close the installer.
Post Installation Tasks
I’ve seen some people suggest restarting SQL Server after applying a CU, but unless the installer asks for it, I don’t find that necessary. To check that the update was applied, open SSMS, connect to your instance, and run this query again:
SELECT @@VERSIONThis time you should see the CU after the version number, along with the KB number (for example Microsoft SQL Server 20xx (RTM-CUxx) (KBxxxxxxx)...).
If the install failed and you need to roll back to the previous version, the instructions for uninstalling that KB are at the bottom of the KB article.
CUs and GDRs
There’s a second kind of update to know about. A General Distribution Release (GDR) is an update Microsoft releases for issues with broad impact, security issues, or both, and it’s the kind that comes through Windows Update. The servicing page says a GDR “can have either an RTM baseline or a CU baseline,” and each baseline has its own line of GDRs. So a server that has only ever received GDRs is on a different line of builds than one that gets CUs. The page has examples for working out which line a given server is on. Its general advice is that “Microsoft always recommends that you install the latest CU that’s available for a given SQL Server version.”
As always, if you run into issues or need help troubleshooting, leave a comment below and I or someone in the community can help.