How to Handle Clustered Index Corruption in SQL Database?

Microsoft SQL Server database is used by several medium and large-sized businesses to store and access their large amount of data safely and securely. Although highly reliable, the database primary MDF file and the secondary NDF file are not immune to becoming corrupt.

There can be several reasons behind corruption of SQL database files. One of the reasons is corruption in clustered index of the database that makes the data stored in MDF and NDF files inaccessible.

How to Check If Index is Corrupted in SQL Server?

If there is corruption in the clustered index in SQL Server, you may encounter an error message that reads as:

Server: Msg 1902, Level 16, State 3, Line 1
Cannot create more than one clustered index on table ‘Table Name’. Drop the existing clustered index ‘Clustered Index Name’ before creating another.

If you haven’t received SQL Server error 1902, you can check if the clustered index is corrupt by following these ways:

• Try fetching SQL Server data from some rows. If there is corruption in an index, then SQL Server will show deleted or different values in the rows of the database.
• Check SQL Server log report to see if the records are edited more than once or not. If you find that the records are edited more than once, it means that the index is corrupted.

What Causes Clustered Index Corruption in MS SQL?

A table can have only one clustered index, as the clustered index dictates the physical storage order of the data in the table. The SQL Server error 1902 indicates that there is more than one clustered index on the table.

How to Fix Clustered Index Corruption in MS SQL?

As a table in SQL Server database can have only one clustered index, it is essential to create any additional indexes on the table as non-clustered. If you wish to alter how the SQL database table is clustered, you need to first drop the existing clustered index before creating a new one.

There are two methods to handle corruption in the clustered index of SQL Server. You can either do it by:
• Restore from Backup
• SQL database repair software

Before We Proceed

Before trying to fix the corrupted clustered index corruption in SQL database, you must try to find the exact reasons behind corruption. You can do so by using the built-in DBCC CHECKDB command. Running this command helps checks the logical and physical integrity of the database and will return you the Database ID, Object ID, and Index ID of the corrupted index.

DBCC CHECKDB (CorruptDBName) With No_InfoMsgs, All_ErrorMsgs,
TableResults;
GO
After checking the index ID, you can easily choose the appropriate action to resolve the issue.

Method 1 – Restore from Backup

If a backup of the SQL server database is present, it can always be restored to get the working copy of the server’s database. However, this page-level restoration method is useful only when there are fewer alterations in the database, and only a single page of the index has been damaged.

If there is corruption in multiple pages of the clustered database, you would have to perform the database level restoration.

Read this: How to Restore Database in SQL Server from .Bak File Step By Step

Method 2 – Use SQL Database Repair Software

The other way to handle SQL database clustered index corruption is using a SQL database repair software that is capable of repairing corrupt or damaged Microsoft SQL Server database (MDF) files safely, securely, and successfully. The use of software makes the process fast and eliminates manual intervention. Also, it is the best alternative when you do not have a backup.

The Way Forward – Stellar Repair for MS SQL

Stellar Repair for MS SQL software easily fixes the clustered index issue. It is an easy-to-use application and provides several benefits along with repairing the damaged SQL Server MDF files. Its additional capabilities are as follows:

• Repairs damaged MDF and NDF files
• Retrieves tables, indexes, triggers, rules, keys, and defaults
• Perform recovery of deleted records
• Searches and recovers specific database objects
• Saves repaired files in MDF (New MS SQL database Or Live MS SQL database), XLS, CSV, and HTML file formats
• Supports MS SQL Server 2019, 2017, 2016, and lower versions

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About The Author

Jyoti Prakash

Jyoti Prakash is a Senior Manager at Stellar Information Technology Pvt. Ltd., having over 15+ years of experience with a background in information technology. A tech enthusiast and expert, he specializes in data recovery, & file repair. He has participated for numerous communities, including Microsoft, SpiceWorks etc. He also provide training on Windows, Microsoft Office, Online Marketing, & social media.