Category : Statistics - SentryOne Team Blog

Category: Statistics

Paul White : Cardinality Estimation : Combining Density Statistics

Paul White : Cardinality Estimation : Combining Density Statistics

Paul White (@SQL_Kiwi) whips out the debugger while showing how SQL Server derives estimates when combining multiple, single-column statistics.

Erin Stellato : Expanding DBCC CLONEDATABASE

Erin Stellato (@erinstellato) goes into detail about some practical use cases for a new DBCC command in SQL Server 2014 SP2 and 2016 : DBCC CLONEDATABASE.

Erin Stellato : Trace Flag 2389 and the new Cardinality Estimator

Erin Stellato shows the combined effect of different versions of the cardinality estimator and trace flag 2389 on an ascending key model.

Jonathan Kehayias : Improved Support for Parallel Statistics Rebuilds

Jonathan Kehayias (@SQLPoolBoy) takes a closer look at a new trace flag that allows you to process multiple concurrent statistics updates on the same table.

Dan Holmes : Custom Built Statistics

Dan Holmes (sql.dnhlms.com) talks about a solution he developed to manually coerce statistics to be more accurate and produce better, more predictable execution plans.

Aaron Bertrand : Please help improve SQL Server statistics!

Aaron Bertrand (@AaronBertrand) highlights three Connect items that will address some pretty important shortcomings in SQL Server statistics.

Erin Stellato : Incremental Statistics are NOT used by the Query Optimizer

Erin Stellato (@erinstellato) of SQLskills demonstrates that, while incremental statistics can help with maintenance, they are ignored by the optimizer.

Erin Stellato : Improving Partition Maintenance with Incremental Statistics

Erin Stellato (@erinstellato) demonstrates the benefits of incremental statistics in SQL Server 2014, and also outlines some unexpected behavior.

Statistics – What, why and how (Part 4)

Lori Edwards (@loriedwards) continues her series on SQL Server statistics, discussing some of the finer details around keeping stats up-to-date.

Statistics – What, why and how (Part 3)

Lori Edwards (@loriedwards) continues her series on SQL Server statistics, this time showing how even up-to-date statistics can yield inaccurate estimates.

Statistics – What, why and how (Part 2)

Lori Edwards (@loriedwards) continues her series on SQL Server statistics, explaining how the optimizer uses cardinality estimates.

Statistics – What, why and how (Part 1)

Lori Edwards (@loriedwards) starts a new series on statistics in SQL Server. In her first post, she discusses what they are and how they are created.

Erin Stellato : Another Reason to Avoid sp_updatestats

Erin Stellato (@erinstellato) of SQLskills explains another reason she avoids the built-in sp_updatestats procedure: it doesn't consider indexed views.

Aaron Bertrand : New Trace Flag to Fix Table Variable Performance

Following the recent release of SQL Server 2012 Service Pack 2, SQL Sentry's Aaron Bertrand (@AaronBertrand) takes a first look at a new performance enhancement and trace flag aimed at improving cardinality estimates for table variables and table-valued parameters.