Query analysis

Ahmad Yaseen

SQL Server 2016 Parameter Sniffing

October 19, 2016 by

SQL Server tries always to generate the most optimized execution plan for each stored procedure the first time that the stored procedure is executed. The SQL Server Engine looks at the stored procedure passed parameter values when compiling the stored procedure, the first execution, in order to create the optimal plan including the parameters and keep that plan for future use in the plan cache. This parameter analysis process is called the Parameter Sniffing.

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Ahmad Yaseen

Troubleshoot SQL query performance using SQL Server 2016 Live Execution Statistics

August 19, 2016 by

SQL Server Management Studio a graphical interactive that allows you to interact with the databases hosted on your servers. SSMS provides you with the ability to write, edit, execute, analyze and monitor your SQL queries. It also helps database administrators answer important questions about the SQL query performance, such as why a query is slow or why an index is not used. The answer to these questions can be found simply by tracking the Query Execution Plan.

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Ahmad Yaseen

Force query execution plan using SQL Server 2016 Query store

July 29, 2016 by

SQL Server Query Store is a new feature introduced in SQL Server 2016 that is used to automatically and asynchronously capture query execution history, statistics and plans, with minimal impact to overall SQL Server Performance. The Query Store feature makes performance problem troubleshooting simple; you can view the query execution plans changes and compare its performance to decide which execution plan the SQL Server Query Optimizer should use for that query.

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Ed Pollack

Searching the SQL Server query plan cache

February 8, 2016 by

Whenever a query is executed in SQL Server, its execution plan, as well as some useful execution data are placed into the plan cache for future use. This information is a treasure trove of metrics that can allow some very useful insight into your server’s performance and resource consumption. Much of this information would be difficult or impossible to acquire otherwise.

Understanding how to access and use the metadata about query execution will provide us the tools we need to answer questions about our server and gain fascinating performance data. I’ve found myself spending more and more time writing, tweaking, and using queries against the plan cache lately and look forward to sharing these adventures with you!

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Ed Pollack

The SQL Server Query Store in Action

November 26, 2015 by

Introduction

The Query Store is a new feature in SQL Server 2016 that will greatly improve the process of performance tuning! The biggest limit of the query plan cache and the dynamic management views that relates to it is that it is very temporary. Queries are only accessible for as long as they are in cache, and as a result there is no way to travel back in time to determine what happened at 9am yesterday, or why performance worsened over a week-long period.

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Brian Bønk Rueløkke

Query Store – the next generation tool for every DBA

November 13, 2015 by

Along with the release of SQL server 2016 CTP 3 now comes the preview of a brand new feature for on premise databases – the Query Store. This feature enables performance monitoring and troubleshooting through the log of executed queries.

This blogpost will cover the following aspects of the Query Store feature:

  • Introduction
  • How to activate it
  • Configuration options
  • What information is found in the Query Store
  • How to use the feature
  • What’s in it for me
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Milena Petrovic

Inaccurate SQL Server statistics – a SQL query performance killer – updating SQL Server statistics

April 28, 2014 by
As shown in the previous part of this series, inaccurate statistics can degrade SQL Server performance. We described how to work with SQL Server statistics using SQL Server Management Studio options and T-SQL. In this article, we will show how to update SQL Server statistics, what are the updating costs, and when updating is recommended. Read more »
Milena Petrovic

Frequent query recompilations – a SQL query performance killer – detection

April 11, 2014 by
In the previous part of this article, we presented query recompilation basics. We explained when a query is compiled, when recompiled, and what preferred behavior is. We also showed the how to trigger a recompilation using T-SQL and provided examples. In this part, we will focus on detecting frequent query recompilations and frequently recompiled queries. Read more »
Milena Petrovic

SQL query performance killers – understanding poor database indexing

March 31, 2014 by
SQL Server performance is affected by many factors. The most common SQL Server performance killers are poor database design, poor indexing, poor query design, not reusable execution plans, frequent query recompilation, excessive fragmentation, and more. With these factors present on your machine, even adding additional hardware resources might not help, as these SQL Server performance killers can use all available resources. Read more »
Milena Petrovic

SQL Server query execution plans – Basics

March 15, 2014 by

Why is query execution important for SQL Server performance?

SQL Server performance monitoring depends on the performance goals. The first step in monitoring is to determine optimal performance for your server and create performance trends based on the captured metric information. If performance is not satisfactory, it’s necessary to diagnose performance problems and find their origin. This involves testing how different queries and applications affect performance Read more »