I have an Access application (linked to SQL database) that contains a form with 4 combo boxes, each one has is own record source as follows.
SELECT Patients.ID, [LastName] & " " & [FirstName] AS Name, Patients.Address, Patients.HomePhone FROM Patients ORDER BY [LastName] & " " & [FirstName];
SELECT Patients.ID, [FirstName] & " " & [LastName] AS Name, Patients.Address, Patients.HomePhone FROM Patients ORDER BY [FirstName] & " " & [LastName];
SELECT Patients.ID, Patients.Address, [FirstName] + ' ' + [LastName] AS Name, Patients.HomePhone
ORDER BY Patients.Address;
SELECT PatientsPhoneUnionQry.ID, PatientsPhoneUnionQry.HomePhone, PatientsPhoneUnionQry.Expr1 FROM PatientsPhoneUnionQry ORDER BY PatientsPhoneUnionQry.HomePhone;
Now when looking at the SSMS Activity Monitor I realized that query #3 is the most expensive one, and is also the one always causing ASYNC_NETWORK_IO, I am wondering why is it that way and what can I do to improve it?
FYI- Currently the table only has a PK clustered index on the ID column, I guess additional indexes would be required, just want to know which one's do you advise.