Thursday, October 11, 2012

What is SQL Server Database Engine Tunning Advisor?

SQL Server Database Engine Tuning Advisor helps you select and create an optimal set of indexes, indexed views, and partitions without requiring an expert understanding of the structure of the database or the internals of SQL Server.
 
SQL Server Database Engine Tuning Advisor analyzes a workload and the physical implementation of one or more SQL Server databases. A workload is a set of Transact-SQL statements that execute against a database or databases that you want to tune. Database Engine Tuning Advisor uses trace files, trace tables, or Transact-SQL scripts as workload input when tuning databases. You can create Transact-SQL script workloads with the Query Editor in SQL Server Management Studio. You can create trace file and trace table workloads by using the Tuning Template in SQL Server Profiler.
 
SQL Server Database Engine Tuning Advisor analyzes the workload and can recommend that you add, remove, or modify physical design structures in your databases. The advisor can also recommend what statistics should be collected to back up physical design structures. The physical design structures include clustered indexes, nonclustered indexes, indexed views, and partitioning. SQL Server Database Engine Tuning Advisor recommends a set of physical design structures that reduces the query optimizers estimated cost of the workload.

SQL Server Database Engine Tunning Advisor Capabilities

 Following is a summary of what SQL Server Tunning Advisor can do for you:
  • Recommend the best mix of indexes for databases by using the query optimizer to analyze queries in a workload.
  • Recommend aligned or non-aligned partitions for databases referenced in a workload.
  • Recommend indexed views for databases referenced in a workload.
  • Analyze the effects of the proposed changes, including index usage, query distribution among tables, and query performance in the workload.
  • Recommend ways to tune the database for a small set of problem queries.
  • Allow you to customize the recommendation by specifying advanced options such as disk space constraints.
  • Provide reports that summarize the effects of implementing the recommendations for a given workload.
  • Consider alternatives in which you supply possible design choices in the form of hypothetical configurations for Database Engine Tuning Advisor to evaluate.
SQL Server Database Engine Tunning Advisor Features

SQL Server Database Engine Tuning Advisor provides new features that enable both novice and experienced SQL Server database administrators to tune databases for better query performance. The following sections list and describe the Database Engine Tuning Advisor new features:

  • Improved Workload Parsing - handles batches that reference transient tables such as temp tables;
  • parses and tunes queries referencing user-defined functions; tunes statements in triggers and a lot more.
  • Enhanced Scalability - uses workload compression, which allows SQL Server Database Engine Tuning Advisor to reduce the amount of time spent tuning while producing high quality tuning recommendation results; uses an algorithm to avoid redundant statistics creation, which reduces the number of I/Os incurred during tuning.
  • Integrated Tuning - SQL Server Database Engine Tuning Advisor can consider the trade offs in performance that are offered by various different types of physical design structures (indexes, indexed views, partitioning). 
  • Multiple Database Tuning - applications often access multiple databases to complete their work, so workloads frequently refer to objects from multiple SQL Server databases. SQL Server Database Engine Tuning Advisor can simultaneously tune multiple databases.
  • Offload of Tuning Overhead to Test Server - tuning a large workload can create significant overhead on the server that is being tuned. This occurs because SQL Server Database Engine Tuning Advisor often needs to make several calls to the query optimizer during the tuning process. Using a test server in addition to your production server eliminates this problem.
  • Command-Prompt Utility and Graphical User Interface Tool - SQL Server Database Tuning Engine Advisor provides a dta command-prompt utility to make it easy to incorporate SQL Server Database Engine Tuning Advisor functionality with scripting and also provides a graphical user interface (GUI) tool, which makes it easy to view tuning sessions and results.
  • Drop-Only Tuning - physical design structures may accumulate over time in a SQL Server database, and database administrators need a way to drop those structures that are no longer useful. The drop-only tuning option is useful for identifying existing physical design structures that are either not used at all or have very little benefit for a given workload.
  • XML Support - all of the tuning operations that you can perform with the SQL Server Database Engine Tuning Advisor GUI and the dta command-prompt utility can be defined in a Database Engine Tuning Advisor XML input file. 
  • User-specified Configuration and "What-if" Analysis Support - SQL Server Database Engine Tuning Advisor enables users to provide a hypothetical configuration of physical design structures (indexes, indexed views, and partitioning strategies) as tuning input. You can then tune a database or databases as if the configuration were already implemented.
  • Analysis Reports - SQL Server Database Engine Tuning Advisor generates several analysis reports in text or in XML after a tuning session completes. These reports provide information such as the cost of queries occurring in the workload, the frequency of events that occur in the workload, or the relationships between queries and the indexes they reference.
  • Tuning Sessions - SQL Server Database Engine Tuning Advisor prompts you to create a unique name or number to identity the tuning session before the analysis can begin. After analyzing a workload or when analysis is stopped, SQL Server Database Engine Tuning Advisor saves the tuning session information and associates it with the identifier you supplied before tuning began.
 Related Tools: If you need to trace multiple SQL Servers on schedule of if you wish to run a profiler trace on SQL Server Express or MSDE you can download the free (free for one SQL Server instance only) xSQL Profiler. xSQL Profiler allows you to configure granular traces and schedule those traces to run on multiple servers at certain time intervals and it automatically aggregates all the trace data from those servers into a central repository database.  Download your free copy from: http://www.xsql.com/download/package.aspx?packageid=12

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