Ahmad Yaseen

Ahmad Yaseen

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 SQL 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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What’s new in SQL Server Management Studio 17.3; Import Flat File wizard and XEvent Profiler

November 1, 2017 by

SQL Server Management Studio is an integrated graphical user interface tool that is used to perform wide range of administration and development tasks on the SQL Server instances, hosted locally on the user machine, remotely on a Windows or Linux server or on SQL Azure or Azure Data warehouse instances hosted in the cloud. You can use SQL Server Management Studio to easily administrate, develop, deploy, configure and monitor the SQL Server instances.

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Constraints in SQL Server: SQL NOT NULL, UNIQUE and SQL PRIMARY KEY

October 25, 2017 by

This article explains the SQL NOT NULL, Unique and SQL Primary Key constraints in SQL Server with examples.

Constraints in SQL Server are predefined rules and restrictions that are enforced in a single column or multiple columns, regarding the values allowed in the columns, to maintain the integrity, accuracy, and reliability of that column’s data. In other words, if the inserted data meets the constraint rule, it will be inserted successfully. If the inserted data violates the defined constraint, the insert operation will be aborted.

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SQL Server Data Type Conversion Methods and performance comparison

October 3, 2017 by

When you define SQL Server database tables, local variables, expressions or parameters, you should specify what kind of data will be stored in those objects, such as text data, numbers, money or dates. This attribute is called the SQL Server Data Type. SQL Server provides us with a big library of system data types that define all types of data that can be used with SQL Server, from which we can choose the SQL Server data type that is suitable for the data we will store in that object. You can also define your own customized user defined data type using T-SQL script. SQL Server data types can be categorized into seven main categories:

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SQL Server 2016 Maintenance Plan Enhancements

September 18, 2017 by

SQL Server Maintenance Plans is a SQL Server Management Studio built-in feature that helps in creating a workflow of variant database administration tasks, which can be run automatically using a predefined schedule or manually triggered by the user.

SQL Server Maintenance Plans allow you to use typical database maintenance tasks or customize your own task using a T-SQL script that runs on the local server or group of SQL Servers, providing more flexibility to the database administration tasks.

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What’s new in SQL Server Management Studio 17.2; Authentication methods, scripting options and more

August 31, 2017 by

SQL Server Management Studio is an integrated graphical interface that is used to configure, manage, monitor and administrate the SQL Server instances hosted on the local machine, on a remote server or in the cloud. It provides us with editing, debugging and deploying environment for the T-SQL, XML, MDX and DMX languages.

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In-Memory OLTP Enhancements in SQL Server 2016

August 22, 2017 by

SQL Server In-Memory OLTP, also known as Hekaton when it was introduced in SQL Server 2014, provides us with the ability to move specific database tables and suitable stored procedures into memory and compile the stored procedures into native x86 code. As a result, you can easily query these database objects directly from memory with the best performance and the least possible data access latency. In addition to that, the SQL Server Engine will no longer use the old latching and locking mechanism to control the data access concurrency. Instead, a high performance row versioning mechanism will be used to control the concurrency. This optimistic concurrency mechanism is 5 times to 20 times faster than the normal disk-based processing, due to reading the data from the memory directly.

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How to simplify SQL Server Database Object usage with Synonyms

July 20, 2017 by

The concept of SQL Server Synonyms was introduced the first time in SQL Server 2005 as an alias name that references an existing database object, replacing its fully qualified name. In this way, it makes the database object more portable and provides more flexibility for the clients to reach and maintain it. You can imagine Synonyms as a layer of abstraction that provides us with an easy way to connect to and manage the database objects without the need to identify the real name and location for these objects.

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How to control online Index Rebuild Locking using SQL Server 2014 Managed Lock Priority

July 18, 2017 by

When you perform a SQL Server Online Index Rebuild operation, introduced for the first time in SQL Server 2005, the index will not be taken down. But at a specific point, in which the new index new is built and switched from the old structure of the index, a special kind of lock, Schema Modification (SCH-M), will be granted. This lock may cause blocking if your database server is busy.

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SQL Server SET Options that Affect the Query Result – SET CONCAT_NULL_YIELDS_NULL, SET NUMERIC_ROUNDABORT, SET QUOTED_IDENTIFIER, SET NOCOUNT, SET XACT_ABORT

July 4, 2017 by

In the previous article of this two-part series SQL Server SET Options that Affect the Query Result – SET ANSI_NULLS, SET ANSI_PADDING, SET ANSI_WARNINGS and SET ARITHABORT, we described the first four SQL Server SET options and showed practically how setting these options ON and OFF affects the SQL Server Database Engine behavior and the query result. To recall, SQL Server SET options are a group of session-level options that control how the SQL Server behaves on the database session level, and the option value can be changed using the SET T-SQL command for the current session that you execute the SET command on.

In this article, we will describe another five SET options and see how turning it ON and OFF will change the SQL Server behavior and the query result.

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SQL Server SET Options that Affect the Query Result – SET ANSI_NULLS, SET ANSI_PADDING, SET ANSI_WARNINGS and SET ARITHABORT

June 30, 2017 by

SQL Server provides us with a number of options to control SQL Server behavior on the connection level. These session-level options are configured using the SET T-SQL command that change the option value for the session on which the SET command is executed. Changing the default value of these session-level configuration affects how the session queries will be executed affecting the query result. The performed change on a session-level option will be applied to the current session until its value is reset or until the current user’s session is terminated.

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SQL Server 2016 Memory-Optimized Tables – The Checkpoint operation

June 21, 2017 by

The SQL Server Database Engine stores data changes in the buffer pool, in memory, before applying it to the database files, for I/O performance reasons. After that, a special kind of background process, called Checkpoint, will write all of these not reflected pages, also known as Dirty Pages, to the database data and log files periodically.

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Compression and decompression functions in SQL Server 2016

June 2, 2017 by

The concept of data compression is not a new on for SQL Server Database Administrators , as it is was introduced the first time in SQL Server 2008. In that SQL Server version, you were able to configure the compression at the row and page levels on the table, index, indexed view or the partition. The row and page level compression is not the best choice in all cases, as it does not work well on the Binary Large Objects (BLOB) datatypes, such as the videos, images and text documents.

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How to add a TDE encrypted user database to an Always On Availability Group

April 27, 2017 by

SQL Server Transparent Data Encryption, also known as TDE, is a “data at rest” encryption mechanism that is introduced in SQL Server 2008 as an Enterprise Edition feature. TDE is used to perform a real-time I/O encryption for the SQL Server database data, log, backup and snapshot physical files, rather than encrypting the data itself, using either Advanced Encryption Standard (AES) or Triple DES (3DES) encryption.

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How to Configure Read-Only Routing for an Availability Group in SQL Server 2016

March 23, 2017 by

The SQL Server Always On Availability Groups concept was introduced the first time in SQL Server 2012 as an enterprise-level high availability and disaster recovery solution that will replace the database mirroring feature. Always On Availability Group provides a high availability solution on the group level, where each group can contain any number of databases that can be replicated to multiple secondary servers known as Replicas.

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