Demo: Identify and fix plan change regression in SQL Server 2017 RC1

Plan change regression happens when SQL Database changes a plan for some T-SQL query, and the new plan has the worse performance than the previous one. SQL Server 2017 has Automatic Tuning feature that enables you to easily find plan change regressions and fix them. In this post you will see the demo script that you… Read more

Monitoring automatic tuning actions using XEvents

SQL Server 2017 can automatically tune your queries by identifying and fixing SQL plan change regressions. SQL Server tracks last known good plans for each query, and if the plan for the query changes, last know good plan will be used if performance of the new plan is worse than the performance of the last… Read more

What is plan regression in SQL Server?

Plan regression happens when SQL Server starts using the sub-optimal SQL plan to execute some T-SQL query. Usually you will see that some T-SQL query is executing really fast, but then it gets slower without any obvious reason. In this post you will see how can plan regression happen…. Read more

“You Shall Not Regress!!!” – How SQL Server 2017 prevents plan regressions?

SQL plan regression is a case when a T-SQL query that executed fine becomes much slower or uses more resources because the underlying SQL plan changed. SQL Server 2017 would not allow that kind of regressions if you enable new automatic tuning feature on your database…. Read more

Query Optimizer Additions in SQL Server 2016

In SQL Server 2016 we have introduced a number of new Query Optimizer improvements. This article summarizes some them and explains you can leverage the benefits of the new enhancements. Expect deep dive follow up articles for some of the enhancements. Here is the short list: Compatibility Level Guarantees Query Optimizer Improvements under Trace Flag… Read more