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SQLEspresso

Monica lives in Virginia and is a Microsoft MVP for Data Platform. She has over 15 years of experience working with a wide variety of database platforms with a focus on SQL Server. She is a frequent speaker at IT industry conferences on topics including performance tuning and configuration management. She is the Leader of the Hampton Roads SQL Server User Group and a Mid‐Atlantic PASS Regional Mentor. She is passionate about SQL Server and the SQL Server community, doing anything she can to give back. Monica can always be found on Twitter (@sqlespresso) handing out helpful tips.

Archives: May 2018

Importance of Statistics

Following up on my last post about the Cardinality Estimator let’s talk about column statistics and how they work and play a part in execution plans. The cardinality estimator relies heavily on statistics to get the answer to selectivity (the ratio of distinct values to the total number of values)… Read more

1 comments, 314 reads

Posted in SQLEspresso on 30 May 2018

Query Predicates

Sometimes people speak “SQL” and expect you know all the terminology. In recent a conversation about query plans I was ranting on and on about how the predicates were written when the person stopped me and asked a very simple question. Like a light bulb going off, it reminded me… Read more

0 comments, 252 reads

Posted in SQLEspresso on 24 May 2018

5 Ways to Examine Cardinality Metrics

In SQL Server the query optimizer uses a cardinality estimator to answer data SELECTIVITY questions like the ones below. The optimizer uses this cardinality data, which relies heavy on statistics to get the answers and calculate a cost estimate. It takes the #of Rows to Satisfy a Predicate/Total # of… Read more

1 comments, 204 reads

Posted in SQLEspresso on 2 May 2018