Milena Petrovic

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 »

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 »

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 »

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 »

SQL Server alerts in troubleshooting performance issues: SQL Server alerting basics

March 14, 2014 by

Why is SQL Server alerting important?

To be aware of what’s going on with your system and how SQL Server performs, monitoring is necessary. However, just monitoring might not be enough. Being notified about a performance issue whenever a specific SQL Server counter meets a threshold value, or a specific event occurs, boosts monitoring usability. These notifications enable DBAs to be aware of every important system performance change as soon as it happens, and therefore they can act immediately to fix the issue and prevent further problems Read more »

Troubleshooting SQL Server issues with sys.dm_os_performance_counters

March 13, 2014 by


sys.dm_os_performance_counters is a system Dynamic Management View (DMV) that returns one row for each SQL Server performance counter. It’s useful for obtaining information about current performance counter values. These counter values are also shown in Windows Performance Monitor, besides other operating system counters Read more »

A DBA guide to SQL Server performance troubleshooting – Part 1 – Problems and performance metrics

March 13, 2014 by
Monitoring SQL Server performance is a complex task, as performance depends on many parameters, both hardware and software. It’s recommended to monitor these parameters proactively in order to prevent any potential performance degradation. However, this is not always the case. If the performance degradation happens, the first step towards the resolution is to determine the problem, find out the cause, and resolve the issue. Severe performance issues require quick actions and resolutions. Less severe problems can have a delayed fix. In either case, DBAs should take actions to prevent these situations in future Read more »

Windows Performance Monitor basics

March 12, 2014 by
Windows Performance Monitor is a tool shipped with Windows that can be used to monitor and examine how applications affect computer performance. It can measure real-time server performance and save the measured values into a log file that can be analyzed later. It enables real time system and SQL Server performance monitoring, tracking the performance impact of applications and services, setting threshold for each monitored metric, and generating an alert or performing a specific action when the defined threshold is exceeded
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