Recently I was asked to troubleshoot a production issue in SharePoint 2010. The web front end servers event log are flooded with Event 2159 - Unified Logging Service and Event ID 5586 - Unknown SQL Exception 297 occurred...
After some research, some pointed out that issue appear after installed December 2011 Update... Which is truth for my case.
And I find my answer at the second part of Thomas's Blog -
I have confirmed that in SQL Server Configuration, the Named Pipes under SQL Server Network Configuration is enabled. Then I asked the DBA to run the Query command for account (the account indicated in red in the event log screenshot) in SQL Management Studio.
GRANT VIEW SERVER STATE TO "Domain\UserAccount"
After that... Event log seem happy ever after... At least for now...
Hope this help!