How to Fix Database Consistency Error in SQL Server When DBCC CHECKDB Fails

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  • Published on
    January 14th, 2019
  • Updated on
    March 1, 2021
  • Read Time
    4 minutes

Summary: The blog highlights the Database consistency error in SQL server along with various reasons behind it and the possible manual and automated resolutions. This error is usually reported by making DBCC CHECKDB command. So, let’s have a look at this particular error.

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For the Database administrators, protection and recovery of the database is the primary task. Generally, the SQL Database works smoothly but at some point of time, it encounters a few errors and thus becomes inaccessible. When users try to execute a DBCC CHECKDB command in the database to check the integrity of the disk. After this, a database consistency error will be displayed in the SQL server.

Database Consistency Error

So, not wasting time anymore, let’s dig out the various reasons that lead to the occurrence of database consistency error in SQL server.

Reasons behind the Database Consistency Error

The DBCC CHECKDB command in the SQL server checks the logical and physical consistency of the database that includes the index relationships, tables, rows, pages etc. If any of these consistency checks fail, an error will be displayed as the command is executed.

There are many reasons that make the occurrence of database consistency error as reported DBCC CHECKDB command.

  • Issue in SQL Server Engine
  • Corrupt pages in memory
  • Hardware system issues
  • Corruption in file system
  • Drive related issues

So, let’s move to the solutions to troubleshoot the SQL Server database consistency error after knowing the reasons.

Methods to Fix Database Consistency Errors in SQL Database

After execution of DBCC CHECKDB command, if there is a failure in the database, a consistency error occurs. This error needs to be fixed in order to ensure smooth functioning of SQL Server. The best solution to repair the database consistency error is to restore the backup data. However, if the users are not able to restore the backup data, CHECKDB can be used to repair the errors. A user must correct the file system or hardware first as it is the main cause of corruption.

The manual solutions to resolve the SQL Server database consistency error has been explained below.

Check the Windows System Event Log

There are some I/O issues due to Windows System Event Log error as a result of which the above-mentioned error occurs. Therefore, a user should run a Windows system event log check for all kind of error. On the basis of inaccessibility of data, there are different event IDs and different solutions for each of them.

Perform the File System Integrity Check

File system integration is another reason behind the SQL database inconsistency. So, it is recommended to perform a system check using the command chkdsk. Using this command, you can get a complete report of the disk status.

Confirm the I/O Requirements of SQL Server

There are some counters related to I/O available in the SQL Database. All of the counters are under some physical and logical disk. These counters are contained in the objects and can handle the logical operations of the hard disk on the system.

Check SQLIOSim Tool

It is another application that can be the reason behind the database consistency error. This tool is used for testing the I/O integrity of the disk system and is independent of SQL server engine. It can be downloaded simply from the web.

Use the Option of Minimum Repair

When a user runs the DBCC CHECKDB command, minimum repair option is run using an approximation that is important to fix the errors.

The following message will be displayed:

CHECKDB found 0 allocation

repair_allow_data_loss is the minimum level of repair for the errors as found by DBCC CHECKDB (AdventureWorks).

It is the minimum repair level to troubleshoot the database consistency errors in SQL server reported by DBCC CHECKDB. But, it is not necessary that every single file will be fixed by this repair option. It just displays those errors which have not been reported by DBCC CHECKDB option.

Alternate Solution to Fix Database Consistency Errors

Sometimes, there is a situation, when all the above methodologies don’t work. So, it is recommended to use a professional tool i.e. SysInfoTools SQL Database Recovery for an efficient and reliable approach. This software is very effective to repair the MDF files in the SQL Database. It restores all the database objects without altering any of the data and information. Solution to Restore Table From SQL Backup. 

Bottom Line

In the above technical script, we have explained the causes for the occurrence of database consistency error in SQL server. Also, the possible manual, as well as automated solutions have been discussed to resolve the error as reported by DBCC CHECKDB command or if the DBCC CHECKDB fails. Hope the article helps.

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