After working with Microsoft for over a month on a daily basis we found the cause of a serious performance issue within SharePoint Online. This issue affected several enterprise customers of ours.
This issue only occurs on sites which use the “managed navigation” functionality. In SharePoint, you can choose between two navigation methods: structural navigation or managed navigation. Structural navigation is based on site structure. Managed navigation is based on term sets. For further information read this article.
Rootcause symptoms which identify the cause:
When clients initiate a webrequest to the SharePoint Online site it takes 5 to 30 seconds untill the server returns data to the GET method. See this screenshot from Internet Exporer “Profiler”.
After intensively troubleshooting several tenants we noticed strange behaviour the way the system communicates with the Managed Metadata Service Application. Since the sites are using managed navigation the content will be represented using a managed metadata term set. Because of this configuration EVERY FIRST WEBREQUEST is relies on your defined term sets and its configuration.
Allright. Now that we have some understanding how the system relies on the Managed Metadata Service Application when using a managed navigation let’s proceed to implementing the solution.
The reason why the system “waits” for over 15 seconds on this specific part of SharePoint is caused by corrupt or missing user permissions on the database of the Service Application. As we explained “Managed navigation is using term store for its items, every time a request made to the term store, it will try to look for these users which takes some time until the process gives up. Therefore causes the delay.”
1. Check if there are “present” Term Store Administrators defined in the Office365 portal by going to the SharePoint Admin center.
2. Select “term store” on the left hand side menu.
3. Check if you see any current users defined or SID’s i.e. s-1-5-21-2522053391-2242016340-1337919630-744690. See the image listed below.
4. If you have identified these unknown SID’s on your environment OR identified other non system service-accounts please feel free to remove the permissions to instantly improve performance.
Now.. if you are using AD FS and DirSync for providing single sign-on access to Office365 services then stick with me. If for instance while developing and building SharePoint solutions several users (developers or admins) have been granted the “Term Set Administrator” permission. At some point the project finishes and their account will be disabled or deleted at the on-premises Active Directory Services. Standard behaviour is that this deletion synchronizes to the cloud with DirSync. This process succesfully deletes the userobject on all front-end systems of Office365 but NOT correctly on all back-end systems in regarding to the Managed Metadata Service Application. In our case the user’s SID was still present on the Managed Metadata SQL database and therefore first webrequests got stuck on this explicit permission.
The only solution for this is contacting Microsoft Support and request them to delete the SID’s and/or old user objects on the database. Once deleted you will instantly notice great performance improvement on your environment!