The goal of the DBA Virtual Group is to provide a PASS community for the DBA. It provides a forum for open discussion and education on issues that face SQL Server database administrators.

Regular Meeting Schedule

The DBA Virtual Chapter holds two webinars each month. The first one is on the second Wednesday at noon, Mountain time and the second one is on the fourth Wednesday at noon, Eastern time. These 1 - 1¼ hour presentations include slides, demos and a time for questions and answers. The meetings are recorded and archived.

Next Meeting

Wed, Apr 26 2017 12:00 Eastern Daylight Time


Think like the Cardinality Estimator – sponsored by Hewlett Packard Enterprise

RSVP: https://attendee.gotowebinar.com/register/7774106142414181633

Think like the Cardinality Estimator

SQL Server uses a phase during query optimization called cardinality estimation (CE). This process makes estimates based on the statistics as to how many rows flow from one query plan iterator to the next. Knowing how CE generates these numbers, will enable you to write better TSQL code and in turn influence type of physical operations during a query execution. Based on that estimated rows, the query processor decides how to access an object, which physical join to use, how to sort the data. Do you know how the CE generates these numbers? If your query has only one predicate, the query optimizer will use the histogram to estimate how many rows will be qualified. What happen when you have multiple predicates, range predicates, variable values that are “NOT KNOWN” to the optimizer or you have predicate values increasing in ascending order? Do you know what will happen if your predicate is using a value that is outside of histogram range? In this session, I will show you how cardinality estimator estimates in all of these scenarios. You will walk out of this session with a clear understanding of how the CE generates its numbers and ready to tackle those nasty, hard to solve query plans.


Taiob Ali, an accomplished technical leader with proven record of success. His experience includes three major business sectors: financial industry, e-commerce and healthcare. He is a Microsoft and MongoDB certified Data professional with over 11 years of IT experience both on premise and cloud. Hands on experience in managing large database projects including large data migration, complex process design, testing and deployment, performance tuning, long term capacity planning. Taiob is currently working at “Grantham, Mayo, Van Otterloo & Co. LLC.” as a DBA lead. Focusing on automation, improving and streamlining operational workflow, plan and prepare for cloud migration. He is a regular speaker at user groups and SQL Saturday events.

Future Meetings

May 10   Noon Mountain

May 24   Noon Eastern

Meeting Recordings

The DBA Virtual Chapter presentations are recorded. On the Meeting Archive page, you will find  .WMV files that can be viewed on-line.

Interested in Presenting to the DBA VC?

We can always use people to give a talk at one of our bi-monthly events. If you are interested in giving a presentation, please send your title, a brief abstract and a brief bio to Sharon Dooley, dbavolunteer@sqlpass.org.

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