SharePoint 2013 Visio Service: the server failed to process the request

Problem

A user reports the following error when attempting to view a Visio web drawing file in his My Site document folder:

Solution

• Ensure that the Visio Graphics Service account is mapped as DBO to the My Site content database.

References

• Visio - bug - The server failed to process the request
• Visio Graphics Service administration in SharePoint Server 2013
• Get-SPServiceApplicationPool
• Get-SPServiceApplication

Notes

• If you added My Site after creating a new Visio Graphics Service, the Visio Graphics Service service account is not automatically mapped to the My Site web application content database.
• To find the Visio Graphics Service identity, you can use IIS or Powershell:
• IIS: launch IIS and view the application pools: select an application pool, and then click View Applications.  eventually you'll find the service account running the service.
• PowerShell: First, look in the Service Applications list for the name of your Visio Service. Then execute this script to generate a list of service applications and their associated application pools:
  

  Get-SPServiceApplication -Name "{Your Visio Service name}"

  Note down the application pool associated with the Visio Graphics Service.  Then execute this script to see a list of application pools and their service accounts:

  Get-SPServiceApplicationPool -Identity "{Your Application Pool  Name}"

  Now you know what service account to map as dbo to the My Site content database.