In this chapter, we will discuss a recently introduced feature: the Query Tuning Assistant (QTA). QTA aims to address some of the most common causes of cardinality estimation related performance regressions that may affect our T-SQL queries after an upgrade from an older version of SQL Server to a newer version, namely SQL Server 2016 and above.
At the time this book is being written, SQL Server 2008 and 2008 R2 are months away from completing their 10-year life cycle and reaching the end of their support; SQL Server 2014 reaches end of mainstream support at the same time; and SQL Server 2012 is no longer in mainstream support. This can raise concerns for all those still running applications supported by these legacy SQL Server versions.
But modernizing the database platform, another word for upgrading in this context...