Alternative of DBCC CHECKDB Repair Allow Data Loss

DBCC CHECKDB is executed on the SQL Server database to check the physical and logical integrity of the database’s integral components. These objects include tables, indexes, keys, stored procedures, triggers, etc. DBCC CHECKDB also checks the structure of all the database tables and indexes. In case any of these checks fail while executing DBCC, you will get an error message that looks similar to the following:

CHECKDB found 0 allocation errors and 15 consistency errors in database ‘dbname’.

repair_allow_data_loss is the minimum repair level for the errors found by DBCC CHECKDB (dbname).

The checks performed by SQL Server DBCC CHECKDB may fail due to issues like file system corruption, driver issues, hardware malfunctioning, problems with the SQL Server engine, and corrupt or damaged pages in memory. See common SQL database corruption errors and their solutions.

What Does DBCC CHECKDB ‘REPAIR_ALLOW_DATA_LOSS’ Fix and What Are The Challenges Associated With It?

Syntax of DBCC CHECKDB with repair options is as follows:

Running DBCC CHECKDB with REPAIR_ALLOW_DATA_LOSS option tries to repair all the database consistency errors. However, the database objects’ integrity is not promised as some data may be compromised or found missing once the command is executed. There are some warning messages associated with REPAIR_ALLOW_DATA_LOSS. These warnings include:

• Although REPAIR_ALLOW_DATA_LOSS is highly supported, it is not always considered as the best option for bringing the database to a consistent state. If the command is successful, it may result in data loss.
• The primary method for recovering the database from errors being reported by database console commands is to restore the database from the last known good backup as recommended by Microsoft. This emergency option is recommended only in case it is impossible to restore from backup.
• It is recommended to create physical replicas of the database files before executing repair operations using REPAIR_ALLOW_DATA_LOSS. The files that need to be copied are MDF (master database file), NDF (secondary database files), and LDF (transaction logs), as well as file stream folders, full-text catalogs, memory-optimized data.
• Always remember to change the state of the database to Emergency mode before initiating the repair process. It is suggested to retrieve all possible data from critical database tables or other objects and save them at an offsite location.

Read this: EMERGENCY-mode repair: the very, very last resort by Paul Randal

What Happens to the Database when REPAIR_ALLOW_DATA_LOSS is Executed?

When a database is put into an Emergency state and SQL Server DBCC CHECKDB with REPAIR_ALLOW_DATA_LOSS is executed, the following actions will take place:

• The given clause recovers the SQL Server database by using log-based recovery strategies.
• If SQL Server database recovery is unsuccessful due to transaction log corruption, the log is rebuilt. The sudden rebuilding procedure could lead to transactional inconsistencies.
• Database pages that are marked inaccessible due to I/O checksum errors are used by DBCC CHECKDB , pretending as if the errors have not occurred. This entire procedure accelerates the prospects of database recovery to a remarkable extent.

Is There an Alternative to DBCC REPAIR_ALLOW_DATA_LOSS?

If DBCC CHECKDB REPAIR_ALLOW_DATA_LOSS does not work or causes data loss, using Stellar Repair for MS SQL software can come in handy. The software can handle all SQL database corruption issues due to server crashes, virus attacks, sudden system shutdown, hardware failure, operating system malfunction, etc. 

One major benefit that the SQL repair tool offers is that it preserves the integrity of MDF and NDF files while repairing the SQL database, making it a potential alternative to DBCC CHECKDB’ REPAIR_ALLOW _ DATA_LOSS’ option.

Benefits of Stellar Repair for MS SQL

The software repairs MDF/NDF files while keeping the data intact. Other benefits that the software offers while repairing database are as follows:

• Repairs database tables, index, triggers, rules, defaults, keys, and other objects
• Can recover deleted records from the SQL tables
• Saves repaired database in 4 different formats, such as MSSQL (.MDF), HTML, CSV, & XLS
• Supports SQL Server database 2019, 2017, 2016, 2014, 2012, 2008, and lower versions
• Trusted and recommended by Microsoft MVPs (MVP recommendations and Best Practices)

In the event of failure, both MDF and NDF files are affected. To efficiently repair SQL Database, it’s important to repair all the components of the master database file and secondary database files.

If any SQL Server disruption occurs, the repair process is paused and automatically resumed when connection to a server is re-established. This helps run the repair process smoothly, ensuring no data is lost during the process.

How Stellar Repair for MS SQL Software Works?

To repair the database using the software, follow these steps:

• Download and launch Stellar Repair for MS SQL

• Select the database that needs to be repaired by clicking on the Browse button. If you do not know the database’s exact location, click on the Search button to select the MDF file from a specific drive.
• Once the database is selected, click the Repair button to start the repairing procedure.
• A preview of all the repairable objects of the database is displayed in the software interface’s left panel. You can click on an object to view its contents in the right pane of the tool.
• Click OK when ‘Selected MS SQL Database repaired successfully‘ message is displayed.
• Next, select the file format in which you want to save the repaired database file, and then click Browse to select the location to save the file.
• If you want to restore the repaired database to the ‘New Database‘ or ‘Live Database’, you need to provide Server credentials. Once complete, click the Save button to proceed further.
• Lastly, click OK when ‘File saved at the desired path’ dialog box appears.

Conclusion

When DBCC CHECKDB reports database consistency errors, you can try restoring the database from an updated backup. If backup is not available or corrupted, the last resort is to run CHECKDB with ‘REPAIR_ALLOW_DATA_LOSS’ option. However, the Repair option can result in data loss and may prevent you from restoring the database to a consistent state. Using Stellar Repair for MS SQL is a better alternative to repair corrupt SQL database without any risk of data loss.