New Cardinality Estimator Part 6 – Simple JOIN And Foreign Key

In this article we will check if PK-FK relationship is respected by new cardinality optimizer in case of a simple JOIN with tables in the mentioned relation. The old CE did not meet expectations, we hope that new CE will handle it better. We will use again the AdventureWorks2012 database and the JOIN between Production.TransactionHistory […]

New Cardinality Estimator Part 5 – Bug?

In this article I will describe a case which is not properly handled by the new cardinality estimator, introduced in SQL Server 2014 CTP2. The discrepancy between estimated and actual values is significant, generated execution plans are sub-optimal and execution details are 5 – 50x worst compared to the old CE plans,. Since performance regression is significant […]

New Cardinality Estimator Part 4 – Single Table and Multiple Predicates

In this article I will explore changes in new CE related to column correlation. As mentioned in my first article about new CE, this change is announced in the paper Testing Cardinality Estimation Models in SQL Server. For this article we will query the table Person.Person from the AdventureWorks2012 database. At the beginning let’s execute […]