Articles tagged

01 October 2018
01 October 2018

Adaptive Query Processing in SQL Server 2017

As new versions of SQL Server have been released, the Query Optimizer has undergone many improvements. Adaptive Query Processing, new in 2017, represents a new direction. This set of features provides some flexibility for varying join types, multi-statement table valued functions, and memory grants. In this article, Robert Sheldon explains the three features that make up Adaptive Query Processing … Read more
31 January 2018
31 January 2018

Matters of Timing in Concurrency

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There are a few topics in SQL Server that I love academically, but are truly a pain to get right. The other is security, and it pales in comparison to how much trouble it is to program for truly safe concurrent access to a resource. The biggest issue: time. What makes it more difficult is … Read more
05 January 2018
05 January 2018

Building a Custom Blocked Process Report

Blocking in SQL Server is normal behavior, but excessive blocking can lead to many complaints and is a symptom of poor performance. SQL Server contains a vast amount of information that can help when troubleshooting performance issues like blocking, but understanding and gathering that information when you need it is a lot of work. Darko Martinovic explains his solution for a custom blocking report.… Read more
06 September 2017
06 September 2017

Six Scary SQL Surprises

The working life of the DBA can be punctuated by surprises, but they aren't generally nice surprises. This is especially true if the DBA is not checking and monitoring the databases for obvious things such as database corruption, and disk space. However, the really scary surprises are less obvious and provide fewer warning signs. Brent Ozar gives six scary surprises that can be avoided by the shrewd DBA.… Read more
04 December 2014
04 December 2014

Questions About T-SQL Transaction Isolation Levels You Were Too Shy to Ask

Every time you access a relational database to make a query, you have an important decision to make: What is the appropriate isolation level for your query? If you get this wrong, the consequences can be serious. Deadlocks, Dirty reads, Non-repeatable reads, or poor performance. We're in luck, because Robert Sheldon once more answers those questions that are awkward to ask in public.… Read more
and 10 September 2014
and 10 September 2014

SQL Server Performance Troubleshooting with SQL Monitor 5

Any SQL Server monitoring tool must gather the metrics that will allow a DBA to diagnose CPU, memory or I/O issues on their SQL Servers. It should also provide a set of accurate, reliable, configurable alerts that will inform the DBA of any abnormal or undesirable conditions and properties, as well as specific errors, on any of the monitored servers. This article provides an in-depth guide to the monitoring and alerting functionality available in one such tool, Redgate SQL Monitor. It focuses on the latest edition (5.0), which includes several key new features, such as performance diagnosis using wait statistics, the ability to compare to baselines, and more.… Read more
16 January 2014
16 January 2014

SQL Server Deadlocks by Example

When a SQL Server instance deadlocks, it can be anything from minor irritation to something far more severe. In this article, Gail Shaw looks at how you can identify common types of deadlock, the difference between a deadlock and severe blocking, and how to avoid and fix the most common deadlock types.… Read more
25 June 2013
25 June 2013

Exploring In-memory OLTP Engine (Hekaton) in SQL Server 2014 CTP1

The continuing drop in the price of memory has made fast in-memory OLTP increasingly viable. SQL Server 2014 allows you to migrate the most-used tables in an existing database to memory-optimised 'Hekaton' technology, but how you balance between disk tables and in-memory tables for optimum performance requires judgement and experiment. What is this technology, and how can you exploit it? Rob Garrison explains.… Read more