Using SQL Server DBCC CHECKDB: What It Catches and What It Misses

While working in the SQL Server environment, users often encounter many issues, like database corruption or any other damage to the database. One of the tools to detect these issues is the SQL Server DBCC CHECKDB command. This is an effective tool to detect the database issues and further resolve them using the repair modes offered by the tool itself. 

In this write-up, we will discuss all the necessary details about the DBCC CHECKDB repair method and also how it helps users resolve database issues efficiently. Without any further delay, let’s learn about the DBCC command in depth.

What is DBCC CHECKDB SQL Server? Explained

The DBCC CHECKDB stands for Database Console Command CHECKDB, and as the name suggests, we can understand that it is a command for the database health. The main role of the SQL Server DBCC CHECKDB command is to check the physical and logical condition of the objects of the database. This command is generally used by the database administrators for database maintenance and detecting any corruption, and resolving it for better performance of the SQL Server database. The basic functions of the DBCC command include the following:

• To Check the System Catalog Consistency
• To verify the Relationship integrity in the database.
• Checking the Indexes and Data pages within the database.

The DBCC CHECKDB command is quite simple to implement. The syntax for implementing the command is as follows:

DBCC CHECKDB (‘DATABASENAME’)        

Running this command will help the users to inspect the database and detect if there are any issues within the SQL Server database. Now, let’s take a look at the reason why the database administrators use the DBCC command for their database health. 

Why Do We Use SQL Server DBCC CHECKDB? 

There are several reasons that demand the use of the DBCC CHECKDB command. Here we will learn these reasons and understand how the command helps the users to resolve their respective database issues. Here are a few of the situations where the DBCC CHECKDB repair command helps users. 

• The command helps to detect the database corruption early. 
• This command also helps users identify the potential issues in the database, preventing the risk of data loss. 
• The DBCC CHECKDB SQL Server is majorly helpful in maintaining the database health in SQL Server. 
• Offers multiple repairing modes to repair any detected corruption or issue in the database. 

For these reasons only, the database administrators prefer using the DBCC CHECKDB command. There are different benefits to using this console command as well. We will now take a look at these advantages to learn why using this repair command is better than going for other options.

How SQL Server DBCC CHECKDB is Beneficial to Users?

There are numerous advantages offered by the command to maintain the database health and repair any issues in the SQL Server database. Here are some of the advantages of using the DBCC CHECKDB repair command. 

• The tool comes with built-in repair modes for database repair after any damage or corruption. These modes help the users to resolve their issues in an efficient manner. 
• The DBCC CHECKDB command helps intensively with the integrity checks in the SQL Server Database. There are various factors where the command helps to check the consistency of the database objects, like system tables,  database indexes, and page-level integrity. 
• Another major benefit of using the DBCC CHECKDB SQL Server is that it helps the database administrators detect any underlying corruption in the database before it creates any more issues in the database. 

With these benefits, it becomes easier for the database administrators to monitor the database health and resolve the issues in the database. Now let’s learn about how to implement the SQL Server DBCC CHECKDB command in the database. 

How to Implement DBCC CHECKDB Command For Database Repair?

The DBCC command is quite straightforward to implement and monitor the database health. To run the DBCC CHECKDB command in SQL Server, the first the users must be aware of is the repair modes and their purposes in the SQL Database repair. 

Moving on to the repair modes in the DBCC CHECKDB command, let’s see what they are and how they work. 

Repair Modes in DBCC CHECKDB Repair 

After the SQL Server DBCC CHECKDB command has examined the database, it generates a report accordingly. And based on these reports, the command offers three options to repair the SQL Database. Here are these modes:

• REPAIR_FAST: 

This repair option helps with the quick recovery of any minor issues or corruptions present in the SQL Server Database. The repair method works to maintain the database by quickly repairing the issues related to the consistency of the database or any structural errors. 

• REPAIR_REBUILD: 

This repair option deals with more sensitive errors than the previous option. The Repair_Rebuild option primarily works with the logical errors, if any, present in the database or database indexes. The major role of this option is to repair and rebuild the damaged index in case server failures. 

• REPAIR_ALLOW_DATA_LOSS:

The REPAIR_ALLOW_DATA_LOSS option deals with corruption by repairing or completely removing the corrupted pages. The option focuses mainly on recovering the database, even if it results in data loss. This method is only used when the user has implemented all the other methods to repair the SQL Database and failed. 

When it comes to running the command with the repair modes, the syntax is not very complex. All the user has to know is what kind of issue they are facing in the database, and then use the repair mode accordingly. The syntax for the same is provided below: 

DBCC CHECKDB (‘DATABASENAME’, REPAIR_FAST);        

We have used the REPAIR_FAST mode considering a situation with minor corruption. Users can change the repair mode as per their requirement or damage severity. 

But is this method completely reliable? There are various factors where the command lacks or create some issues for the database administrators. We will now try to understand the limitations of this method to learn where the method fails. 

What SQL Server DBCC CHECKDB Misses During Database Monitoring?

Even though the DBCC CHECKDB SQL Server is helpful in most scenarios, it still misses out certain things during the corruption check in the database. Here are the factors that the DBCC command misses during the database inspection. 

• If the database has performance issues like slow queries or other issues related to missing indexes, etc., this might get missed during the database check with the DBCC CHECKDB repair command. 
• Another factor that can be missed with the DBCC command is the issues during the SQL Server Log Shipping and Replication process. The DBCC cannot find issues in the log shipping or replication process. 
• The SQL Server DBCC CHECKDB might fail to detect any issues regarding the database security or passwords. 

The DBCC CHECKDB often fails to detect certain aspects of the SQL Database, leading to bigger issues and creating challenges for the database administrators to resolve the errors. 

When situations like these occur, we suggest using a professional solution that will not only help the users detect corruption in the database but also help repair the database corruption. Let’s take a closer look at which solution we are talking about and how the solution can help us with database maintenance. 

Effective And Advanced Alternative to DBCC CHECKDB

We will now understand how an advanced solution like the SQL Recovery Tool can help users detect any corruption in the database more precisely. Furthermore, the solution is capable of recovering the data after corruption and saving it to the SQL Server database or even in the SQL Server-compatible scripts, as per the user’s need. Let’s take a look at how the solution works and is better than SQL Server DBCC CHECKDB.

1. The first step is to install and launch the expert solution.
2. Next, click on the open tab to add the files in the software panel.
3. To check for any corruption, select one option from Quick or Advanced Scanning modes. The Quick Scan mode helps detect minor corruption in the database, whereas the advanced scan mode helps detect severe corruption in the database. 
4. When the scan is complete, preview the recovered data in the software. 
5. Click the export button. Enter the destination path details where you wish the files to be saved.
6. Select the export with schema and data option. 
7. After entering the required details, click on the OK button to export the data to the specified location. 

The steps to use the professional solution are quite simple to understand and follow. With this solution, it becomes easier to recover data after any corruption in the database. The DBCC CHECKDB SQL Server can be helpful for the database administrators in several situations, but wherever the method fails, we can efficiently use the expert solution. 

Conclusion 

In this technical write-up, we have tried to understand the SQL Server DBCC CHECKDB command. We have covered all the relevant information about the command to make it easier and clearer for the users to understand. We have also explained the limitations of the DBCC CHECKDB SQL Server command to help the users understand the situation where they can use an expert solution to resolve their issues.