VMware vSphere Client could not connect to vCenter version 5.1.0

Recently we had an issue, where we were unable to connect to one of our VMware ESXi vCenter’s (v5.1.0) with vSphere Client. Everything worked, all virtual machines were up, except vCenter. Digging deeper, the log files revealed the following: 2014-09-19T09:01:09.494+03:00 [02156 warning ‘Default’] [VdbStatement] SQL execution failed: cleanup_events_tasks_proc 2014-09-19T09:01:09.494+03:00 [02156 warning ‘Default’] [VdbStatement] Execution elapsed […]