Symptoms

Whenever we try to refresh a specific service instance, we get a SQL timeout. We use a custom DLL to interface with a database that provides data to K2 that is used in workflows. This started occurring after upgrading from K2 4.5 1420 to 4.6.9. See attached screenshots and SQL code.
 

Diagnoses

This was happening with all instances, that suggested that all inactive reporting instances were affecting the refresh interval. After running some queries we determined that they needed to be deleted.
 

Resolution

Deleting the Inactive Service Instances fixed this issue. After querying the database we found out that there was a hi volume of inactive instances preventing the Service Instance from refreshing.

Each time you deploy a smartobject or create a service instance, do modifications to it, it adds a new one and changes the status to no active.