Ahmad Yaseen

Ahmad Yaseen

Ahmad Yaseen

Ahmad Yaseen is a SQL Server database administration leader at Aramex International Company with a bachelor’s degree in computer engineering as well as .NET development experience.

He is a Microsoft Certified Professional with a good experience in SQL server development, administration, performance tuning, monitoring and high availability and disaster recovery technologies. Also, he is contributing with his SQL tips in many blogs

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Ahmad Yaseen

Latest posts by Ahmad Yaseen (see all)

SQL Server Execution Plans types

July 23, 2018 by

In the previous article, we described, in detail, the different stages that a submitted SQL Server query goes through and how it processed by the SQL Server Relational Engine. The SQL Server Relational Engine generates the Execution Plan and the SQL Server Storage Engine performs the requested data retrieval or modification process. In this article, we will discuss the different types and formats for SQL Server Execution Plans.

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SQL Server Execution Plans overview

July 4, 2018 by

In this series of articles, we will navigate the SQL Server Execution Plan ocean, starting from defining the concept of the Execution Plans, walking through the types, components and operators of Execution Plans analyze execution plans and we’ll finish with how to save and administrate the Execution Plans.

When you submit a T-SQL query, you tell the SQL Server Engine what you want, but without specifying how to do it for you. Between submitting the T-SQL query to the SQL Server Database Engine and returning the query result to the end user, the SQL Server Engine will perform four internal query processing operations, to convert the query into a format that can be used by the SQL Server Storage Engine easily use to retrieve the requested data, using the processes assigned to the SQL Engine from the Operating System to work on the submitted query.

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SQL Server indexes – series intro

June 29, 2018 by

Description

In this series, we will dive deeply in the SQL Server Indexing field, starting from the surface by understanding the internal structure of the SQL Server tables and indexes, going deeper by describing the guidelines and best practices that we can follow to design the most efficient index and what operations can be performed on the created indexes. Having these knowledges about the SQL Server indexes, we have all the tools that help us in testing the lower part of the ocean and dive deeper with the two main types of the SQL Server Indexes; the Clustered and Non-Clustered, and the other types of indexes that can be customized to serve us improving your environment. After that, the adventure becomes more interesting when learning how to use this knowledge to tune the performance of our queries and touch the bottom of the ocean. In our way back to the surface, and before celebrating our achievements, we will collect statistical information about these indexes and use this information to maintain the indexes to take benefits from it continuously and gain the best application performance.

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Top 25 interview questions and answers about SQL Server indexes

June 25, 2018 by

Q1: What is the difference between a Heap table and a Clustered table? How can we identify if the table is a heap table?

Heap table is a table in which, the data rows are not stored in any particular order within each data page. In addition, there is no particular order to control the data page sequence, that is not linked in a linked list. This is due to the fact that the heap table contains no clustered index.

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Maintaining SQL Server indexes

May 31, 2018 by

In the previous articles of this series (see the full article TOC at bottom), we discussed the internal structure of SQL Server tables and indexes, the guidelines that you can follow in order to design a proper index, the list of operations that can be performed on the SQL Server indexes, how to design effective Clustered and Non-clustered indexes, the different types of SQL Server indexes (above and beyond Clustered and Non-clustered indexes classification), how to tune the performance of the inefficient queries using different types of SQL Server Indexes and finally, how to gather statistical information about index structure and the index usage. In this article, the last article in this series, we will discuss how to benefit from the previously gathered index information in maintaining SQL Server indexes.

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Gathering SQL Server indexes statistics and usage information

May 24, 2018 by

In the previous articles of this series (see the full article TOC at bottom), we discussed the internal structure of both the SQL Server tables and indexes, the best practices that you can follow in order to design a proper index, list of operations that you can perform on the SQL Server indexes, how to design effective Clustered and Non-clustered indexes, the different types of SQL Server indexes, above and beyond Clustered and Non-clustered indexes classification and finally how to tune the performance of the bad queries using the different types of SQL Server Indexes. In this article, we will discuss how to gather statistical information about the index structure and the index usage information.

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Tracing and tuning queries using SQL Server indexes

May 18, 2018 by

In the previous articles of this series (see the full article TOC at bottom), we discussed the internal structure of the SQL Server tables and indexes, the best practices to follow when designing a proper index, the group of operations that you can perform on the SQL Server indexes, how to design effective Clustered and Non-clustered indexes and finally the different types of SQL Server indexes, above and beyond Clustered and Non-clustered indexes classification. In this article, we will discuss how to tune the performance of the bad queries using SQL Server Indexes.

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Working with different SQL Server indexes types

May 8, 2018 by

In the previous articles of this series (see the full article TOC at bottom), we discussed the internal structure of both SQL Server tables and indexes, the main guidelines that you can follow to design a proper index, the list of operations that can be performed on the SQL Server indexes, and finally how to design effective Clustered and Non-clustered indexes that the SQL Server Query Optimizer will always take benefits from, in speeding up the data retrieval process, which is the main goal of creating an index. In this article, we will go through the different types of SQL Server indexes, above and beyond Clustered and Non-clustered indexes classification, and when to use them.

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Designing effective SQL Server non-clustered indexes

May 7, 2018 by

In the previous articles of this series (see below for the full index of articles), we went through the internal structure of SQL Server tables and indexes, listed a number of guidelines that help in designing a proper index, discussed the operations that can be performed on SQL Server indexes and finally showed how to design and create a SQL Server Clustered index to speed up data retrieval operations. In this article, we will see how to design an effective Non-clustered index that will improve the performance of frequently used queries that are not covered with a Clustered index and, in doing so, enhance the overall system performance.

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Designing effective SQL Server clustered indexes

May 3, 2018 by

In the previous articles of this series (see bottom for a full index), we described, in detail, the structure of SQL Server tables and indexes, the basics and guidelines that help us in designing a proper index and finally the list of operations that can be performed on the SQL Server indexes. In this article, we will see how we could design an effective clustered index that the SQL Server Query Optimizer will always take benefits from, in speeding up the data retrieval process, which is the main goal of building an index.

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SQL Server index operations

April 19, 2018 by

In the previous articles of this series, we described the structure of the SQL Server tables and indexes, the main concepts that are used to describe the index and the basics and guidelines that are used to design the proper index. In this article, we will go through the operations that can be performed on the SQL Server indexes.

Creating Indexes

Before creating an index, it is better to follow the index design guidelines and best practices that are described in the previous article, to determine the columns that will participate in the index, the type of the created index, the suitable index options, such as the FillFactor or Sort in TempDB, and the storage location of that index.

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What’s new in SSMS 17.5; Data Discovery and Classification and more

April 16, 2018 by

SQL Server Management Studio aka SSMS is the default integrated graphical user interface tool that is used to access, administrate, configure, manage, query and monitor the different SQL Server instances that are hosted locally at the user machine, remotely on a server or anywhere in the cloud. It is a comprehensive environment that allows us to edit, debug and deploy scripts written in different languages such as T-SQL, DAX, MDX, XML and more.

In my previous articles, we followed the enhancements to the existing SSMS features, the fixes to the bugs found and reported in the previous SSMS versions and the new features added to each new release. These new features that are introduced in the previous versions include the Connections dialog box new options, the embedded Performance Dashboard, Showplan node search, Import Flat File Wizard, the XEvent Profiler and Always On Availability Group dashboard new additions, which are described deeply in these articles.

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SQL Server index structure and concepts

March 19, 2018 by

In my previous article, SQL Server Table Structure Overview, we described, in detail, the difference between Heap table structure, in which the data pages are not sorted in any ordering criteria and the pages itself are not sorted or linked between each other, and Clustered tables, in which the data is sorted within the data pages and the pages will be also linked in a double linked list, based on the index key. In this article, we will go through the structure of the SQL Server index, itself.

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SQL Server table structure overview

March 7, 2018 by

Microsoft SQL Server is a relational database management systems (RDBMS) that, at its fundamental level, stores the data in tables. The tables are the database objects that behave as containers for the data, in which the data will be logically organized in rows and columns format. Each row is considered as an entity that is described by the columns that hold the attributes of the entity. For example, the customers table contains one row for each customer, and each customer is described by the table columns that hold the customer information, such as the CustomerName and CustomerAddress. The table rows have no predefined order, so that, to display the data in a specific order, you would need to specify the order that the rows will be returned in. Tables can be also used as a security boundary/mechanism, where database users can be granted permissions at the table level.

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SQL Server table hints – WITH (NOLOCK) best practices

February 14, 2018 by

SQL Server table hints are a special type of explicit command that are used to override the default behavior of the SQL Server query optimizer during the T-SQL query execution This is accomplished by enforcing a specific locking method, a specific index or query processing operation, such index seek or table scan, to be used by the SQL Server query optimizer to build the query execution plan. The table hints can be added to the FROM clause of the T-SQL query, affecting the table or the view that is referenced in the FROM clause only.

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What’s new in SQL Server Management Studio 17.4; Always On AG dashboard enhancements and more

December 27, 2017 by

As all other database engines that require a GUI too to interact with, Microsoft built SQL Server Management Studio as a tool that provides an environment to manage, configure, monitor and administrate the SQL Server infrastructure for different kind of instances, that are installed locally at your machine, on a remote server with Windows or Linux operating systems or hosted in the cloud such as SQL Azure or Azure Data warehouse.

Recall that the SQL Server Management Studio consists of the Object Explorer, which is used to view and manage all objects within the SQL Server instance, the Template Explorer, that is used to deal with the scripting text files and the Solution Explorer, that is responsible for building the projects that contain list of T-SQL scripts in SQL Server.

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SQL Server read-ahead mechanism; concept and performance gains

December 21, 2017 by

The user’s read requests in SQL Server are managed and controlled by the SQL Server Relational Engine, that is responsible for determining the most optimized access method, such as index scan or table scan, to retrieve the requested data. These read requests are also optimized internally by the SQL Server Storage Engine, the buffer manager components specifically, that is responsible for determining the general read pattern to be performed.

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What to choose when assigning values to SQL Server variables: SET vs SELECT T-SQL statements

November 29, 2017 by

SQL Server provides us with two methods in T-SQL to assign a value to a previously created local variable. The first method is the SET statement, the ANSI standard statement that is commonly used for variable value assignment. The second statement is the SELECT statement. In addition to its main usage to form the logic that is used to retrieve data from a database table or multiple tables in SQL Server, the SELECT statement can be used also to assign a value to a previously created local variable directly or from a variable, view or table.

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