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The Complete Guide to SQL Server System Databases

by Dev on

Hey there! this is the 3rd article in the category “SQL Server DBA Tutorial: Beginners to Pro”. Here we are going to discuss about SQL Server System databases. The prior article in this series is Understanding SQL Server Versions and Editions

Introduction

To begin with, when you install SQL Server, it creates the system databases automatically. Understanding the role of system databases is crucial. Here we are going to explore everything you need to know about SQL Server system databases,
including their purpose, components, and best practices for managing them.

Table of Contents

  • What are System Databases?
  • Importance of System Databases
  • Understanding the Core System Databases
    • Master
    • Model
    • Msdb
    • Tempdb
    • Resource Database
  • Distribution Database
  • Best Practices to maintain the System Databases

What are System Databases?

System databases are the backbone of a SQL Instance. Each of them play a critical role in the functioning of the database management system. These databases provide critical services to the server and user databases. Each system database has a specific purpose, and they work in harmony.

Importance of System Databases

System databases contain crucial information about the SQL Server instance, including server-level configurations, system objects, and metadata. Understanding the purpose and components of these databases is essential for efficient database management, backup and recovery, and overall system stability.

Understanding the Core System Databases

Now let’s take a deep dive into the core System Databases. The below image shows the system databases when you connect to a SQL Instance.

System Databases

Master Database:

Contains all the system-level information for an instance of SQL Server. The master database is the most important as it is necessary for starting the SQL Server.

This includes instance-wide metadata such as logon accounts, endpoints, linked servers, and system configuration settings.

Also, master is the database that records the existence of all other databases and the location of those database files and records the initialization information for SQL Server. Therefore, SQL Server cannot start if the master database is unavailable.

Model Database:

The model database is used as a template for other databases created in SQL Server, especially when creating user-defined databases.

The entire configuration of the model database, including database options, are copied to the newly created database.

Every time SQL Server is started, it creates tempdb from model hence if model is corrupted, SQL will not come up normally.

Msdb Database: 

The msdb database is used mainly by the SQL Server Agent, and also by other features like SQL Server Management Studio, Service Broker, and Database Mail.

SQL Server automatically maintains a complete online backup-and-restore history within tables in msdb.

Tempdb Database:

TempDB is a global resource that is accessed by all the users in the SQL Server Instance

This stores temporary user objects that you create like temporary tables (Global and Local), temporary variables, temporary stored procedures that hold intermediate results during the sorting or query processing, and cursors.

Internal objects like Work Tables, Work files. Intermediate sort results for operations such as creating or rebuilding indexes.

Version stores, which are collections of data pages that hold the data rows that support features for row versioning.

Resource database:

The Resource Database is a hidden, read-only database that contains system objects, system catalogs, and metadata.

SQL Server system objects, such as sys.objects, are physically persisted in the Resource database, but they logically appear in the sys schema of every database. The Resource database does not contain user data or user metadata.

Microsoft created this database to allow very fast and safe upgrades. You can’t see the database by selecting from sys.databases or
executing sp_helpdb. It also won’t show up in the system databases tree in the Object Explorer pane
of SQL Server Management Studio, and it doesn’t appear in the drop-down list of databases from your query windows.

However, this database still needs disk space.
You can see the files in your default binn directory by using Microsoft Windows Explorer. For Example: C:\Program Files\Microsoft SQL Server\MSSQL11.MSSQLSERVER\MSSQL\Binn

mssqlsystemresource.mdf,  and mssqlsystemresource.ldf files.

To explain refer the below screen shot:

System Databases

Distribution Database:

SQL Server creates this database when you configure Replication on SQL Server and you choose the SQL Instance to act as a distributor. It stores replication metadata, history, and the transactions to replicate to other servers.

Best practices to Maintain System Databases:

Create a robust backup strategy for Regular backups of system databases.

Make proper SOP for restoring the system databases so that it is easier in the event of a disaster. Not to mention knowing how to restore system databases is essential for recovering your SQL Server instance.

Managing the size of system databases, especially TempDB, can significantly impact server performance. Hence proper Sizing and Growth Planning is very essential.

Equally important is monitoring solutions to keep an eye on the health and performance of your system databases.

In addition Consider placing system databases on separate disks to prevent contention and optimize performance.

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Understanding SQL Server Versions and Editions

by Dev on

SQL Server Versions and Editions

Microsoft SQL Server is a popular database management system. It comes in different versions and editions, each with its own set of features and capabilities. Understanding the differences between SQL Server versions and editions can help you choose the right one for your organization’s needs. Here we’ll build the basic understanding of the terms and will not go into details.

This is second article in the SQL Server DBA Tutorial: Beginners to Pro series. You may want to read the first article What is SQL Server

SQL Server Versions

SQL Server continuously improves its features and capabilities by releasing different versions building upon the previous ones. The current version of SQL Server is SQL Server 2022, but previous versions, such as SQL Server 2019, 2017, 2016 and 2014 still widely used. Each version of SQL Server includes new features and enhancements that can improve performance and scalability.

There are other EOL (End Of Life) versions such as SQL Server 2012, 2008R2, 2008, 2005 and 2000.

As an illustration if I have to brief you about few of SQL Sever Versions:

SQL Server 2022:

The newest SQL Server version released on 16th November 2022. This is the most Azure-enabled version yet, building on its tradition of performance, security, and availability.

SQL Server 2019:

Microsoft launched SQL Server 2019 on November 4, 2019. Introduces Big Data Clusters for SQL Server. This lets you analyze your data on-fly using T-SQL and spark.

SQL Server 2017:

Launched on October 2, 2017. First time, Microsoft made the SQL Server compatible with Linux.

SQL Server 2016:

Introduced Always Encrypted in SQL 2016 in all editions. Prior to SQL Server 2016 (13.x) SP1, Always Encrypted was limited to the Enterprise Edition only.

SQL Server 2014:

Released to manufacturing on March 18, 2014, and released to the general public on April 1, 2014.

In essence, with each version Microsoft comes up with enhanced and robust features.

SQL Server Editions

SQL Server is also available in different editions, each with a specific set of features and capabilities. The most common editions of SQL Server are:

Standard Edition: This edition is suitable for small to medium-sized businesses and includes features such as basic backup and recovery, basic security, and basic reporting.

Enterprise Edition: Top-end edition with a full feature set. Basically large enterprises use this edition and includes advanced features such as advanced security, advanced data warehousing, and advanced reporting.

Express Edition: This edition is a free, entry-level version of SQL Server that is ideal for small to medium-sized applications and includes basic features such as basic backup and recovery, basic security, and basic reporting.

Web Edition: This edition provides basic features like basic backup and recovery, basic security, and basic reporting for web-based applications

Developer Edition: This is similar to Enterprise. Another free edition but only for development and testing environments.

Compact Edition: Microsoft SQL Server Compact 4.0 is a free, embedded database that software developers can use for building ASP.NET websites and Windows desktop applications.. The maximum size of the database is 4 GB.

Evaluation: The SQL Server Evaluation Edition is a great way to get a fully functional and free instance of SQL Server for learning and developing solutions. This edition has a built-in expiry of 6 months from the time that you install it.

Business Intelligence: Data warehousing and business intelligence applications uses this edition and includes advanced BI capabilities such as reporting and analysis services.

 Keep in mind that the feature set and limits of the different editions may change with new releases of SQL Server, so it’s best to check the specific product documentation for the most up-to-date information.

Conclusion

In Summary choosing the right SQL Server versions and editions can be challenging, especially when you consider the different features and capabilities that each version and edition provides. Thus by understanding the differences between SQL Server versions and editions, you can make an informed decision.

Hence it is important to keep in mind that the version and edition of SQL Server you choose will depend on the size of your organization, the type of data you need to store, and the features and capabilities you need to support your organization’s specific use cases.

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What is SQL Server

by Dev on

Introduction to SQL Server

In this blog post, we will discuss What is SQL Server. You will learn its features, and how it manages and stores large amounts of data for organizations of all sizes.

What is SQL Server?

First thing to know is Microsoft Developed SQL Server and hence it is also called as MS SQL Server. It is a powerful RDBMS that allows organizations to store, manage, and retrieve data. Moreover SQL Server can handle both structured and unstructured data and work with a wide range of data types. SQL Server manages data for a variety of applications, including enterprise resource planning (ERP), customer relationship management (CRM), and data warehousing.

Features of SQL Server

SQL Server offers a wide range of features that make it a powerful tool for managing and storing data. Some of the key features of SQL Server include:

  • Scalability: SQL Server can scale up or down to meet the needs of any organization, from small businesses to large enterprises.
  • High availability: SQL Server can be configured for high availability to ensure that data is always available and that there is minimal downtime.
  • Security: SQL Server includes a variety of security features to help protect data from unauthorized access.
  • Business Intelligence: SQL Server equips a variety of business intelligence (BI) tools that allows users to analyze and visualize data.
  • Cloud-ready: SQL Server’s availability in both on-premise and cloud-based versions makes it easy to deploy and manage in any environment.

SQL Server usage

SQL Server can manage and store data for a wide range of applications. Some of the most common uses of SQL Server include:

  • Data warehousing: SQL Server stores and manages data for data warehousing applications. This allows organizations to analyze and report on large amounts of data.
  • Business Intelligence: SQL Server also stores and manages data for BI applications. This allows organizations to analyze and visualize data for decision making.
  • Website and Application: Many websites and applications uses SQL Server serves as a backend, it also stores and retrieves data quickly and efficiently.

In conclusion, SQL Server is a powerful RDBMS which stores, manages, and retrieves data for a wide range of applications. As can be seen, with its wide range of features and scalability, it is well-suited for organizations of all sizes. If you’re looking for a powerful and flexible tool for managing your data, SQL Server is a great option to consider.

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