Unable to upload and access documents in SharePoint 2013 after BLOB Externalization (4306443)

Symptom

Users cannot upload and access documents within a web application that is scoped to an active RBS Storage Profile in SharePoint 2013.

The following entry in the SharePoint Trace Log File (ULS log) means that the service accounts do not have EXECUTE permissions on the RBS Stored Procedures in the content database:

System.Data.SqlClient.SqlException (0x80131904): The EXECUTE permission was denied on the object 'rbs_fn_get_blob_reference', database '', schema 'mssqlrbs'.
   at System.Data.SqlClient.SqlConnection.OnError(SqlException exception, Boolean breakConnection, Action`1 wrapCloseInAction)
   at System.Data.SqlClient.TdsParser.ThrowExceptionAndWarning

The simple solution is to give the account db_owner and db_rbs_admin role in the content database scoped in the profile. The more complicated solution is to assign the EXECUTE permission to the user or its group for the stored procedure. Please refer below for the detailed steps:

1. In SQL Server Management Studio, connect to the SQL server instance with the content database.
2. Expand Databases > affected content database > Security > Users.
3. Select the user account for the SharePoint Farm Administrator, SharePoint Timer Service, SharePoint Web Application Pool and other service (if using Visio and Excel) accounts. Right-click on them, then select Properties.
4. On the Membership page, select db_rbs_admin and db_owner roles, then click OK.

Reference: The EXECUTE permission was denied on the object 'xxxxxxx', database 'zzzzzzz', schema 'dbo'