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SQLServerCentral Article

SSC Clinic: Can Implementing "Optimize for Ad Hoc Queries" Boost Performance for the SQLServerCentral.com and Simple-Talk.Com SQL Servers?

With the introduction of the instance-level option “optimize for ad hoc workloads” in SQL Server 2008, DBAs have a tool to deal with a problem known as plan cache pollution, or plan cache bloat. It’s often caused when one-time use ad hoc queries are sent to SQL Server from Object-Relational Mapping (ORM) solutions, such as LINQ, NHibernate, or Entity Framework. The problem can prevent SQL Server from using its available memory optimally, potentially hurting performance.

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2012-06-14

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External Article

SQL Server Prefetch and Query Performance

Prefetching can make a surprising difference to SQL Server query execution times where there is a high incidence of waiting for disk i/o operations, but the benefits come at a cost. Mostly, the Query Optimizer gets it right, but occasionally there are queries that would benefit from tuning.

2012-06-14

4,026 reads

External Article

A first look at SQL Server 2012 Availability Group Wait Statistics

If you are trouble-shooting an AlwaysOn Availability Group topology, a study of the wait statistics will give a pointer to many of the causes of problems. Although several wait types are documented, there is nothing like practical experiment to familiarize yourself with new wait stats, and Joe Sack demonstrates a way of testing the sort of waits generated by an availability group under various circumstances.

2012-06-12

2,331 reads

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Question of the Day

Getting the Average

I have this data in the dbo.Commission table in a SQL Server 2022 database.

salesperson commission
Brian       12
Brian       16
Andy        7
Andy        14
Andy        21
Steve       20
Steve       NULL
All the data is a varchar, and I decide to run this query to get the totals for each salesperson.
SELECT SalesPerson
     , AVG(TRY_PARSE(Commission AS int)) AS TotalCommission
 FROM commission
 GROUP BY SalesPerson
GO
What average commission is calculated for Steve?

See possible answers