The Query Store captures a history of queries, execution plans, and runtime statistics, which persist within SQL Server and can be reviewed later.  Read more...

Using new features and changing code can cause problems in your environment. Always test to be sure that the impact is acceptable.  Read more...

Developer shops may decide to use Read Committed Snapshot Isolation (RCSI) to reduce contention, and possibly improve performance, but it is not without its own pitfalls. In this article, Uwe Ricken describes a situation where long running transactions caused a severe performance degradation when RCSI was in use.  Read more...

Developers need to consider not only system performance when writing code, but also how readability impacts code maintenance.  Read more...

SQL Server Missing Index Detail Script  Read more...

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You’ve been performance tuning queries and indexes for a few years, but lately, you’ve been running into problems you can’t explain. Could it be RESOURCE_SEMAPHORE, THREADPOOL, or lock escalation? These problems only pop up under heavy load or concurrency, so they’re very hard to detect in a development environment.  Read more...

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As security threats proliferate, the need for encryption will continue to rise. We who are the Guardians of the Data must be ready to make SQL Server respond and to manage the performance issues that are inherent in every data encryption solution.  Read more...

Script to get the index scan count and Average Fragmentation(since last restart)  Read more...

CosmosDB has ways to tune performance based on throttle metrics. We probably need some DevOps style feedback and adjustment for relational systems.  Read more...

When your application is running slowly, the reflex action is to blame the database queries. It is certainly true that some of the more extravagant delays can be fairly blamed on a missing index or unnecessary locking, but there are other potential villains in the drama, including the network and the application itself. Dan Turner points out that you could save a lot of time and money by working out for sure where the problems lie before diving into the detail.  Read more...

A SQL Server, SQL Azure and Hekaton performance bench marking application that uses patterns.  Read more...

An account of a recent encounter we had with a peculiar wait event which was initially misdiagnosed.  Read more...

Any DBA who is trying to find the cause of an intermittent problem with a server or database dreams of being able to use a query or procedure take a snap of the relevant variables at the point when the problem occurred. Laerte takes an example of a slow-running query hogging resources to show that you can run queries when a WMI alert is fired, and save the results for later inspection, whenever it happens.  Read more...

Erik Darling explains why your queries aren't scaling in production.  Read more...

Aaron Bertrand shows a quick demo that illustrates why you should be very careful about oversizing varchar / nvarchar columns.  Read more...

Aaron Bertrand shows a quick demo that illustrates why you should be very careful about oversizing varchar / nvarchar columns.  Read more...

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Paul White walks through a new trace flag in SQL Server 2016 designed to yield better execution plans (and performance) for queries involving computed columns.  Read more...