How to Repair Index Corruption in SQL Server Databases?

Indexes in the database tables may become damaged, inconsistent, or corrupt due to unexpected process termination, data storage failures, or RAM issues. Because of this index corruption, the queries may fail to execute or fetch the wrong results. To remedy this situation, you would need to reorganize or rebuild the corrupted indexes with the help of SQL server commands.

Let’s delve deeper into this issue and find feasible solutions to repair index corruption in SQL server databases. We will also briefly discuss clustered and nonclustered index corruptions followed by their resolution. Finally, we will talk about Stellar Repair for MS SQL, an SQL database repair tool that can fix all index corruption in a quick and user-friendly manner. While this tool can deal with index corruption, it can also perform MDF repair, thus fixing even complex corruptions in the MDF files.

Index Corruption in your Database

You can identify a corrupted index with the below messages:

Error: 823, Severity: 24, State: 2.

Error 824, Severity: 24, State: 2.

Error 832:

You may detect these corruptions with the help of SQL Server Logs in SQL Server Management Studio

Just follow this path: Object Explorer –> Management –>SQL Server Logs.

Alternatively, you may also use DBCC CHECKDB Command to detect index corruption

DBCC CHECKDB(‘SQL_TEST_DB’) –> This command will check your Database for index corruption

DBCC CHECKDB(‘SQL_TEST_DB’) WITH NO_INFOMSGS; –> This command will be helpful if you do not want to see informational messages

DBCC CHECKDB(‘SQL_TEST_DB’) with TABLERESULTS; –> This command will list the errors in table format

Repairing Index Corruption using DBCC CHECKTABLE

You may use DBCC CHECKTABLE command to repair index corruption in the SQL Server databases. Especially, if only a single index is corrupt in the entire database, running this command will be the best solution to repair the damaged index. We will understand this with an example.

Let’s assume a table named ‘Car’ in a database named SQL_TEST_DB. The command DBCC CHECKTABLE will find errors in this table.

DBCC CHECKTABLE(‘[car]’);    

If the table is corrupt, repairing it for the proper functioning of your database becomes inevitable. This necessitates the need to set the database containing the corrupt table in the Single_User mode before proceeding. Here is the requisite command.

ALTER DATABASE [SQL_TEST_DB]

SET SINGLE_USER WITH ROLLBACK IMMEDIATE;

You may now proceed to repair the corrupted table and index with the following syntaxes:

REPAIR FAST

DBCC CHECKTABLE (‘[car]’, REPAIR_FAST);

This syntax takes care of backward compatibility only. It does not perform any repair action.

REPAIR ALLOWS DATA LOSS

The REPAIR_ALLOW_DATA_LOSS option strives to repair all the errors reported in a table. During the process, it can lead to significant data loss.

DBCC CHECKTABLE (‘[car]’, REPAIR_ALLOW_DATA_LOSS);

You should use this option only as the last resort when no other command can repair the index corruption issue. It is because by using this option, the user himself allows SQL SERVER to delete data to repair the corrupted table.

REPAIR_REBUILD

Using REPAIR_REBUILD is still a comparably safer option, as it will rebuild only nonclustered indexes to deal with the corrupted data.

DBCC CHECKTABLE (‘[car]’, REPAIR_REBUILD);

It can perform quick repairs (such as repairing missing rows) as well as time-consuming repairs (index rebuilding).

As you can infer, these manual methods are error-prone and can lead to the loss of your crucial data. Trying an SQL database repair tool, such as Stellar Repair for MS SQL would be a feasible choice in this context. Let’s move to clustered index corruption next.

Handling clustered index corruption

Despite being reliable, you cannot sideline the possibility of corrupt MDF and NDF files, making them inaccessible. Of the many reasons, a corrupted clustered index is a major factor behind the inaccessibility of the data contained in these MDF and NDF files.

You can identify the corruption in the clustered index by error messages as given below:

Server: Msg 1902, Level 16, State 3, Line 1

Factually, a table can contain only one clustered index, as the latter signifies the order of the physical storage of the data in the table. Nevertheless, the SQL Server Error 1902 indicates the presence of multiple clustered indexes in a table. This causes a contradiction, leading to clustered index corruption.

Perhaps a backup restore would be sufficient to handle this kind of corruption. If things do not work out, performing MDF repair with the help of an SQL database repair tool would be a bankable solution.

Especially, if you are using Stellar Repair for MS SQL, you can rest assured of prompt and satisfying resolution of the issue.

Handling nonclustered index corruption

A nonclustered index corruption happens mainly because of the NOLOCK hint. It tends the query to read the table value incorrectly. At times, the query also reads a particular value more than one time.

Microsoft keeps rolling out regular patches to resolve this corruption issue. In case the patches do not work as intended, you can run the ALTER INDEX REBUILD command.

Alternatively, you can drop and recreate a nonclustered index in SQL Server Management Studio (SSMS). Here is how you can navigate to this task:

Object Explorer –> Database Table (right click) –> Script Table As –> Drop And Create To

While this move can resolve the corruption issue, the problem may reoccur or may not have found its resolution properly.

Using SQL database repair tool to fix index corruption

You can fix any type of index corruption with the help of an SQL database repair tool. While many software are available to execute this task, Stellar Repair for MS SQL ensures prompt and satisfying resolution. It performs hassle-free NDF and MDF file repair to set the database free from corruption. Here are some of its prominent features:

• Fixes all types of database corruption
• Repairs corrupt SQL files
• Fixes corrupt tables, indexes, stored procedures, keys, triggers, etc.
• Restores clustered and non-clustered indexes to a new database
• Performs MDF repair to make it accessible
• Offers multiple options for file saving

To know more about this SQL database repair tool to perform MDF repair, fix index corruption, or carry out any other repair task, you can contact the company directly. The software is available at a reasonable price, thus encouraging you to prefer it to other manual methods. It will surely save you considerable time and money.