Recently, while supporting a high-traffic SharePoint 2010 Enterprise farm running the December 2012 CU, I came across a bug worth noting. A publishing site running on the farm started to experience increased page load-times and eventually was unable to render at all, causing a SharePoint Correlation ID to be generated. With the Correlation ID in hand, I used the light-weight ULS Viewer to take a look at the actual errors.
These entries in the log proved to be crucial in identifying the issue:
Unexpected: Unexpected query execution failure in navigation query….
High: An unexpected error occurred while manipulating the navigational structure of this Web...
Unexpected: Unexpected PortalSiteMapProvider was unable to fetch children for node at URL: /YourSite/YourSubSite….
As indicated in the logs, I knew there was a possible issue with the navigation control of a specific web in my publishing site. A quick search led me to this MSDN SharePoint blog by Joerg Sinemus, describing a bug introduced by the SharePoint 2010 August 2012 CU. The bug erroneously causes duplicate entries in the dbo.NavNodes table of the SharePoint content database, eventually rendering the database unusable.
Armed with that newfound information, I opened up SQL Management Studio and expanded the Tables directory of the content database containing the site identified in the ULS log. Right-clicking the dbo.NavNodes table and selecting the Top 1000 Rows confirmed the issue. Using the Name column of the query results, I was able to quickly identify the problematic publishing page causing the navigation control to fail, as there were several hundred rows with the same entry.
With the URL of the affected site and the name of the problematic publishing page, I was able to use SharePoint Designer to open the site and delete the page – removing the duplicate entries from the table and restoring site performance. The page can then be restored from the Recycle Bin.
Looking ahead to a long-term resolution, Microsoft Support has indicated that the SharePoint 2010 April 2013 CU contains the fix for the duplicate NavNodes issue.