Databases Reference
In-Depth Information
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.
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