Dissecting Sql Server Execution Plans

Download or read book The Art of High Performance SQL Code written by Grant Fritchey and published by . This book was released on 2009-03 with total page 242 pages. Available in PDF, EPUB and Kindle. Book excerpt: Execution plans show you what's going on behind the scenes in SQL Server. They can provide you with a wealth of information on how your queries are being executed by SQL Server, including: Which indexes are being used, and where no indexes are being used at all. How the data is being retrieved, and joined, from the tables defi ned in your query. How aggregations in GROUP BY queries are put together. The anticipated load and the estimated cost that all these operations place upon the system. Grant Fritchey's book is the only in-depth look at how to improve your SQL query performance through careful design of execution plans. Sample chapters of the ebook have garnered stunning reviews, such as: "All I can say is WOW. This has to be the best reference I have ever seen on Execution Plans in SQL Server. My hats off to Grant Fritchey" Jonathan Kehayias.

Download or read book SQL Server Execution Plans written by Grant Fritchey and published by Red Gate Books. This book was released on 2018-10 with total page 520 pages. Available in PDF, EPUB and Kindle. Book excerpt: If a query is performing poorly, and you can't understand why, then that query's execution plan will tell you not only what data set is coming back, but also what SQL Server did, and in what order, to get that data. It will reveal how the data was retrieved, and from which tables and indexes, what types of joins were used, at what point filtering, sorting and aggregation occurred, and a whole lot more. These details will often highlight the likely source of any problem. I wrote this book with the singular goal of teaching you how to read SQL Server Execution plans It will explain, among many other things, the following: How to capture execution plans using manual and automatic methods A documented method for reading and interpreting execution plans How common SQL Server objects, such as indexes, views, stored procedures, and so on, appear in execution plans How to control execution plans with hints and plan guides, and why this is a double-edged sword How the Query Store works with, and collects data on, execution plans With this knowledge, you'll have everything you need to read the execution plan, for any query of your own, regardless of complexity, and understand what it does and what is causing the bad performance. It is still your job to work out how best to fix it, but your new understanding of execution plans will give a much better chance of success!

Download or read book SQL Server Execution Plans written by Grant Fritchey and published by Red Gate Books. This book was released on 2012 with total page 344 pages. Available in PDF, EPUB and Kindle. Book excerpt: Every day, out in the various online forums devoted to SQL Server, and on Twitter, the same types of questions come up repeatedly: Why is this query running slowly? Why is SQL Server ignoring my index? Why does this query run quickly sometimes and slowly at others? My response is the same in each case: have you looked at the execution plan? An execution plan describes what's going on behind the scenes when SQL Server executes a query. It shows how the query optimizer joined the data from the various tables defined in the query, which indexes it used, if any, how it performed any aggregations or sorting, and much more. It also estimates the cost of all of these operations, in terms of the relative load placed on the system. Every Database Administrator, developer, report writer, and anyone else who writes T-SQL to access SQL Server data, must understand how to read and interpret execution plans.My book leads you right from the basics of capturing plans, through how to interrupt them in their various forms, graphical or XML, and then how to use the information you find there to diagnose the most common causes of poor query performance, and so optimize your SQL queries, and improve your indexing strategy.

Download or read book Mastering SQL Server Profiler written by Brad McGehee and published by Red Gate Software. This book was released on 2009 with total page 306 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Python for Software Design written by Allen Downey and published by Cambridge University Press. This book was released on 2009-03-09 with total page 273 pages. Available in PDF, EPUB and Kindle. Book excerpt: Python for Software Design is a concise introduction to software design using the Python programming language. The focus is on the programming process, with special emphasis on debugging. The book includes a wide range of exercises, from short examples to substantial projects, so that students have ample opportunity to practice each new concept.

Download or read book Pro Spatial with SQL Server 2012 written by Alastair Aitchison and published by Apress. This book was released on 2012-07-25 with total page 553 pages. Available in PDF, EPUB and Kindle. Book excerpt: Microsoft SQL Server implements extensive support for location-based data. Pro Spatial with SQL Server 2012 introduces SQL Server’s spatial feature set, and covers everything you'll need to know to store, manipulate, and analyze information about the physical location of objects in space. You’ll learn about the geography and geometry datatypes, and how to apply them in practical situations involving the spatial relationships of people, places, and things on Earth. Author Alastair Aitchison first introduces you to SQL Server’s spatial feature set and the fundamental concepts involved in working with spatial data, including spatial references and co-ordinate systems. You’ll learn to query, analyze, and interpret spatial data using tools such as Bing Maps and SQL Server Reporting Services. Throughout, you'll find helpful code examples that you can adopt and extend as a basis for your own projects. Explains spatial concepts from the ground up—no prior knowledge is necessary Provides comprehensive guidance for every stage of working with spatial data, from importing through cleansing and storing, to querying, and finally for retrieval and display of spatial data in an application layer Brilliantly illustrated with code examples that run in SQL Server 2012, that you can adapt and use as the basis for your own projects.

Download or read book Performance Tuning with SQL Server Dynamic Management Views written by Louis Davidson and published by Fastprint Publishing. This book was released on 2010 with total page 344 pages. Available in PDF, EPUB and Kindle. Book excerpt: Dynamic Management Views (DMVs) are a significant and valuable addition to the DBA's troubleshooting armory, laying bare previously unavailable information regarding the under-the-covers activity of your database sessions and transactions. Why, then, aren't all DBAs using them? Why do many DBAs continue to ignore them in favour of "tried and trusted" tools such as sp_who2, DBCC OPENTRAN, and so on, or make do with the "ready made" reports built into SSMS? Why do even those that do use the DMVs speak wistfully about "good old sysprocesses"? There seem to be two main factors at work. Firstly, some DBAs are simply unaware of the depth and breadth of the information that is available from the DMvs, or how it might help them troubleshoot common issues. This book investigates all of the DMVs that are most frequently useful to the DBA in investigating query execution, index usage, session and transaction activity, disk IO, and how SQL Server is using or abusing the operating system. Secondly, the DMVs have a reputation of being difficult to use. In the process of exposing as much useful data as possible, sysprocesses has been de-normalized, and many new views and columns have been added. This fact, coupled with the initially-baffling choices of what columns will be exposed where, has lead to some DBAs to liken querying DMVs to "collecting mystic spells." In fact, however, once you start to write your own scripts, you'll see the same tricks, and similar join patterns, being used time and again. As such, a relatively small core set of scripts can be readily adapted to suit any requirement. This book is here to de-mystify the process of collecting the information you need to troubleshoot SQL Server problems. It will highlight the core techniques and "patterns" that you need to master, and will provide a core set of scripts that you can use and adapt for your own systems, including how to: * Root out the queries that are causing memory or CPU pressure on your system * Investigate caching, and query plan reuse * Identify index usage patterns * Track fragmentation in clustered indexes and heaps * Get full details on blocking and blocked transactions, including the exact commands being executed, and by whom. * Find out where SQL Server is spending time waiting for resources to be released, before proceeding * Monitor usage and growth of tempdb The DMVs don't make existing, built-in, performance tools obsolete. On the contrary, they complement these tools, and offer a flexibility, richness and granularity that are simply not available elsewhere. Furthermore, you don't need to master a new GUI, or a new language in order to use them; it's all done in a language all DBAs know and mostly love: T-SQL.