Welcome to the world of Performance Monitoring and Tuning with SQL Server 2012!
Let's assume that you are a database administrator in your organization. What, if one day one of your colleagues from your IT department calls you right away and complains that the production database server has abruptly started to run very slowly and applications that are accessing the production database are not responding the way they should? The issue needs immediate attention and for that you are required to investigate the issue and fix it in timely manner. What will be your approach to look at the problem and solve it? How would you be able to analyze the situation and identify where the problem is? What actions would you take once a particular problem is recognized in order to resolve it?
Installing and upgrading database servers, managing and maintaining database servers, managing database security, implementing disaster recovery plan, capacity planning, managing high-availability of databases, and performance tuning of databases and SQL server are some of the responsibilities of a DBA. Amongst these responsibilities, performance tuning of the database server is one of the prime responsibilities of DBA. The most common reason is, companies offering IT services are often engaged in signing Service Level Agreements (SLAs) and as per their SLAs they are committed to provide a certain level of services and up-time. Any additional down-time than what is allowed as per SLAs can cause them money loss or business loss. Even companies not engaged in SLAs might lose business because of their poor software systems caused by poor database systems. This is one of the reasons why skilled DBAs are required to keep the database performance up-to date by monitoring and tuning database performance.
In database centric application environment, it is very common for any DBA to face such database related performance issues at different levels. By means of different levels, it implies that performance problem can be found at query level, database level, server level or application level .There can be a number of reasons for a database centric application to be performing poorly. The troubleshooting skills and expertise in performance tuning of a DBA are tested out in recognizing such factors behind the performance degradation and taking the necessary corrective steps.
The first step towards performance tuning is monitoring. In data platform, monitoring something is the process of analyzing and identifying something. So, until you monitor something, you can't know for sure what and where the problem is. Until you know what and where the problem is, you can't analyze the problem. And until you can analyze the problem, you can't solve a problem! This also means that unless you understand performance monitoring, you cannot master performance tuning in a true sense. Thus, performance tuning always comes after performance monitoring. This is the reason why we have a few opening chapters that specifically concentrates on performance monitoring.
The troublesome situation that was just described earlier needs thorough monitoring and systematic analysis in order to identify the root problem accurately before a problem can be solved.
SQL Server Profiler is the most common but powerful tool for monitoring and auditing an instance of SQL server. By using this tool, a DBA is able to solve a large number of different types of database performance issues whether it is a query issue, index issue, locking issue or database, or server configuration issue. It is the tool that essentially any DBA must know. So, SQL Server Profiler will be the subject of this first chapter.