A Quick Guide to SQL Server Recovery Models

SQL Server Recovery Models: A Quick Guide

The transaction logs are managed by a recovery model in a Structured query language (SQL) Server, which controls how they are logged, backed up, and restored. A master database file (MDF) and a log database file (LDF) are both included in the SQL Server database (LDF). All database objects, such as tables, stored procedures, and information, are saved in the MDF file. All logs, such as transactions that occur in a database, are stored in the LDF log file. There seem to be three kinds of efforts to improve in SQL Server:

• Simple
• Full
• Model for bulk-logged recovery.

In this blog post, we’ll look at finding the existing model in our database, the advantages and disadvantages of the three SQL Server recovery models, and how to modify the model.

How to find the existing recovery model in SQL Server

You may find out your Database’s current recovery model by utilizing one of the methods below.

SQL Server Management Studio is a tool for managing SQL Server databases.
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Using SQL Server Management Studio, follow these simple steps to determine what the current recovery model is:

1. To begin, launch SQL Server Management Studio. 
2. Then, right-click on the Database and choose Properties from the drop-down menu.

1. 

2. 

3. The Database Properties window will now display on the screen—select Options from the left pane of that window. The current recovery model in your database will then be shown.
   Take a look at the image below.

Query in SQL

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You can also find the recovery model in a database by running the SQL query below.​

SELECT name, recovery_model_desc FROM sys.databases WHERE name = 'My_Database_Name' ;

Three types of recovery models in SQL Server

The backup and restoration options for a database are determined by the three recovery types (primary, complete, and bulk-logged). Depending on the recovery model, we can restore data if the database malfunctions or crashes.

The simple model of recovery
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The most basic recovery technique in SQL Server is the simple recovery model. Every completed transaction in this model causes the transaction log records to be immediately removed. As a result, transaction log backups are not supported; only full or differential backups are kept.

If the database fails or crashes, you can restore it using the most recent complete or differential backup. When using the simple recovery paradigm, we cannot do a point-in-time restoration. As a result, updated data between the most recent full or differential backup and the moment of failure may be lost.

Advantages

• Because the basic recovery approach automatically removes the transaction logs, the disk space required is minimal. 
• Compared to the complete and bulk-logged recovery methods, it takes minor administration. 

Disadvantages

• The simple recovery paradigm has one fundamental flaw: it does not support point-in-time restore. As a result, in the case of a database failure, data may be lost.
• This recovery technique is not appropriate for an organization’s production databases because it will not tolerate data loss. 

Model of complete recovery

The transaction logs are kept in SQL Server’s complete recovery model until they are backed up. We may restore the database using this paradigm at any point and lose no data.

Like the simple recovery model, the comprehensive recovery model keeps track of transaction logs. It will not, however, automatically erase them after each completed transaction. The transaction logs also capture the creation and alteration of indexes and insert and update transactions. Because each transaction is logged, resulting in a large log file. As a result, management must keep a constant eye on the expanding log size.

The database will fail to admit new transactions until the transaction log is backed up or truncated if the transaction log becomes full.

Advantages

• We can go back to any point in time and restore the data. As a result, this model assists us in avoiding data loss. 

Disadvantages

• The transaction log file is enormous, and it continues to grow in size with each transaction. 
• The administration must keep a close eye on the expanding log size. 
• The database will reject new transactions if the transaction log is complete. 

Model for bulk-logged recovery
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The total recovery model and the bulk-logged recovery model are comparable. The only difference is when conducting bulk-logged actions like bulk insert, select into, and build the index. The transaction log size is reduced. As a result, compared to the full recovery model, the transaction log size in this approach is modest.

Due to the low logging of bulk transactions, the bulk-logged recovery approach improves the performance of massive bulk processes. In some circumstances, this model will not reconstruct a moment in time. Only if no bulk-logged activities are conducted during the period of database malfunctions or crashes may a point-in-time restore be performed.

If you do a measurement process, we can only restore the database to the last transaction log before recording the bulk operation.

Advantages

• Compared to the complete recovery approach, the transaction log file size will not grow dramatically. 
• Point-in-time restoration is also possible in the bulk-logged recovery approach, but only in certain circumstances. 
• Due to limited logging, this paradigm improves the performance of bulk processes. 

Disadvantages

• In some circumstances, point-in-time restoration isn’t possible.

How to change the recovery model

Before modifying a database’s recovery model, we must first examine the Database’s activities. It is suggested that we adjust the recovery model when the database activity is low. 

We need to perform a thorough database backup before changing the recovery model. We can quickly return it to its original state if anything goes wrong.

To alter the restoration model of a SQL database, utilize one of the methods below.

SQL Server Management Studio is a tool for managing SQL Server databases.
​
To modify the recovery model in SQL Server Management Studio, follow these steps:

1. To begin, launch SQL Server Management Studio. 
2. Then pick Properties from the right-click menu on Database. 
3. The Database Properties window will now display on the screen. Select Options from the left pane of that window. 
4. Then, from the drop-down menu, choose the new recovery model.
5. Finally, to apply the changes, click Ok.

   Query in SQL

   You can also modify a database’s recovery model with the SQL statement below.

USE [My_Database_Name] ; ALTER DATABASE [My_Database_Name] SET RECOVERY FULL ;

Conclusion

We hope you now understand the three different SQL Server recovery models, check which one is used, and modify it in your database. Try out the methods in this blog post, and let us know what you think in the comments!

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