In this article, we will discuss how to read the SQL Server execution plan (query plan) with all aspects through an example, so we will gain some practical experience that helps to solve query performance issues. Interpreting query plans correctly is the first and major principle to troubleshoot query performance issues. When we try to find an answer to the “why is this query running slow?” question, the best starting point would be to analyze the query plan.
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In this article, we will explore how the ORDER BY statement affects the query performance and we will also learn some performance tips related to sorting operations in SQL Server.
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The SQL Server execution plan (query plan) is a set of instructions that describes which process steps are performed while a query is executed by the database engine. The query plans are generated by the query optimizer and its essential goal is to generate the most efficient (optimum) and economical query plan. Some query plans that are created by the query optimizer contain some interesting characteristics. In this article, we will go into details of these interesting query plans.
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Gaining experience in SQL query tuning can be very difficult and complicated for database developers or administrators. For this reason, in this article, we will work on a case study and we are going to learn how we can tune its performance step by step. In this fashion, we will understand well how to approach query performance issues practically.
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In this article, we will briefly explain the SUBSTRING function and then focus on performance tips about it.
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In this article, we will discuss the Dirty Read concurrency issue and also learn the details of the Read Uncommitted Isolation Level.
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In this article, we will analyze a simple T-SQL query execution plan with different aspects. This will help us to improve our practical skills instead of discussing theoretical knowledge.
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In this article, we will learn the basics of Parallel Execution Plans, and we will also figure out how the query optimizer decides to generate a parallel query plan for the queries.
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In this article, we will explore the Composite Index SQL Server and the impact of key order on it. We will also view SQL Server update statistics to determine an optimized execution plan of the Compositive index.
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This article gives an overview of viewing execution plans in the Azure Data Studio.
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In this article, I’m going to explain what the Execution Plans in SQL Server are and how to understand the details of an execution plan by reading the various metrics available once we hover over the components in the plan.
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In this article, we will learn the SQL Average function which is known as AVG() function in T-SQL. AVG() function is an aggregate function that calculates the average value of a numerical dataset that returns from the SELECT statement.
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In this article, we will discuss a few very common questions that you may be asked during a SQL Server administrator or developer technical job interview.
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This article will provide an overview of SQL Server implicit conversion including data type precedence and conversion tables, implicit conversion examples and means to detect occurrences of implicit conversion
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In the previous articles of this series (see the index at bottom), we discussed the characteristics of the SQL Execution Plan from multiple aspects, that include the way the SQL Execution Plan is generated by the SQL Server Query Optimizer internally, what are the different types of plans, how to identify and analyze the different components and operators of the Execution Plans, how to work with the plans using different tools and finally, tuning the performance of simple and complex T-SQL queries using the Execution Plans. In this, the last article of this series, but not the least, we will discuss where the Execution plan is stored and how to save it for future use.
A SQL index is used to retrieve data from a database very fast. Indexing a table or view is, without a doubt, one of the best ways to improve the performance of queries and applications.
A SQL index is a quick lookup table for finding records users need to search frequently. An index is small, fast, and optimized for quick lookups. It is very useful for connecting the relational tables and searching large tables.
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In the previous articles of this series (see the index at bottom), we went through many aspects of the SQL Execution Plan, where we discussed how the Execution Plan is generated internally, the different types of plans, the main components and operators and how to read and analyze the plans that are generated using different tools. In this article, we will show how we can use an Execution Plan in tuning the performance of T-SQL queries.
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Database administrators are used to dealing with query performance issues. As part of this duty, it is an important aspect to identify the query and troubleshoot the reason for its performance degradation. Normally, we used to enable SET STATISTICS IO and SET STATISTICS TIME before executing any query.
In the previous articles of this series (see the index at bottom), we discussed many aspects of the SQL Execution Plans, starting with the main concept of SQL Execution Plan generation, diving in the different types of the plans and showing how to analyze the components and operators of the SQL Execution Plans.
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This article will provide an overview of the SSMS 18.0 with particular focus on improvements to the SQL execution plan feature. To work with Microsoft SQL Server Database Engine, you need to have an environment to edit, debug and deploy scripts written in different languages such as T-SQL, DAX, MDX, XML and JSON. In addition, you need a GUI tool that helps you to configure, query, monitor and administrate your SQL Server instances wherever they are hosted; locally at your machine, on a remote Windows or Linux server or in the cloud. All this can be achieved using SQL Server Management Studio aka SSMS.
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In the previous articles of this series, we went through three sets of SQL Server Execution Plan operators that you will meet with while working with the different Execution Plan queries. We described the Table Scan, Clustered Index Scan, Clustered Index Seek, the Non-Clustered Index Seek, RID Lookup, Key Lookup, Sort, Aggregate – Stream Aggregate, Compute Scalar, Concatenation, Assert, Hash Match Join, Hash Match Aggregate , Merge Join and Nested Loops Join Execution Plan operators. In this article, we will dive in the fourth set of these SQL Server Execution Plan operators.
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In the previous articles of this series, we discussed a group of SQL Server Execution Plan operators that you will face when studying the SQL Execution Plan of different queries. We showed the Table Scan, Clustered Index Scan, Clustered Index Seek, the Non-Clustered Index Seek, RID Lookup, Key Lookup and Sort Execution Plan operators. In this article, we will discuss the third set of these SQL Execution Plan operators.
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In the previous article, we talked about the first set of operators you may encounter when working with SQL Server Execution Plans. We described the Non Clustered Index, Seek Execution Plan operators, Table Scan, Clustered Index Scan, and the Clustered Index Seek. In this article, we will discuss the second set of these SQL Server execution plan operators.
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In the previous articles of this series, SQL Server Execution Plans overview , SQL Server Execution Plans types and How to Analyze SQL Execution Plan Graphical Components, we discussed the steps that are performed by the SQL Server Relational Engine to generate the Execution Plan of a submitted query and the steps performed by the SQL Server Storage Engine to retrieve the requested data or perform the requested modification operation.
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In the previous articles of this series, SQL Server Execution Plans overview and SQL Server Execution Plans types we went through the different stages that the submitted SQL Server query followed and how it processed by the SQL Server Relational Engine that generates the Execution Plan and the SQL Server Storage Engine that performs the requested data retrieval or modification operation. In addition, we described deeply the different types and formats of the SQL Server Execution Plans that can be used for query performance troubleshooting purposes. In this article, we will discuss the graphical query plan components and how to analyze them.
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