Microsoft has just added support for query hints to Azure SQL Database, giving database administrators a powerful tool to manage the performance of ISV application code. Here's how it works.

Figure 1. Execution plan of a server query. As you can see in the above execution plan, SQL Server has highlighted a missing index that it thinks would help our query improve.

What is a query execution plan? SQL Server has an optimizer that usually does a great job of optimizing code for the most effective execution.