Hi Friends, In this video, I am demonstrating one of the ways How SQL Server performs Cardinality Estimation - it’s always good to know more about SQL Server internals and architecture. Hope you enjoy the video. Do share it. You can also visit our Your Tube channel to watch more videos. Want to read a [...]
Hi Friends, Read Part 1 & Part 2. SQL Server Cardinality Estimation is a complicated topic until you understand the internals of SQL Server Statistics. Here are some quick notes that will answer some common questions that you generally have: How does SQL Server Query Optimizer perform cardinality estimation in case of multiple columns? Let’s [...]
Hi Friends, A few days back I penned down a few quick notes about Cardinality Estimation in SQL Server. You can read Part 1 here. SQL Server Cardinality Estimation is a complicated topic until you understand the internals of SQL Server Statistics. Here are some quick notes that will answer some common questions that you [...]
Hi Friends, SQL Server Cardinality Estimation is a complicated topic until you understand the internals of SQL Server Statistics. Here are some quick notes that will answer some common questions that you generally have: How does SQL Server Query Optimizer estimate a default cardinality? Let’s see and example (turn ON Actual Execution Plan or press [...]
Hi Friends, Here is a short explanation of the SQL Server statistics histogram. I am using AdventureWorks2008R2 database. There is a table Sales.SalesOrderHeader with a column TotalDue. Let us have a look at that column. USE AdventureWorks2008R2 GO -- first observe the rows select TotalDue from Sales.SalesOrderHeader GO select DISTINCT TotalDue from Sales.SalesOrderHeader GO You [...]
