What to Do When DBCC CHECKDB Repair Allow Data Loss is Not Working

As an SQL Server user, you must be aware that SQL Server Database is immune to corruption. That’s why an administrator needs to have a recovery plan for worst-case scenarios. So let’s discuss can DBCC CHECKDB Repair be trusted to for database recovery. The DBCC CHECKDB has three repair option like REPAIR_ALLOW_DATA_LOSS, Repair_Fast & Repair_Rebuilt that helps in repairing of your corrupted SQL Database. This blog also explains the alternate methods when DBCC CHECKDB REPAIR_ALLOW_DATA_LOSS does not work.

Using an SQL Server Database is not a simple task because it is vulnerable to corruption and repairing it can really become problematic sometimes. That is why many of the users are moving from standard SQL management to intelligent SQL Management as it can repair quickly, vigorously, and tactically corrupted SQL Server Database. Using DBCC CHECKDB command is a smart and convenient method used by SQL Database Administrators to crawl database. It can check whether there is any irregularity or any database backup maintaining issue. Doing so regularly helps to strategize if any corruption occurs.

How Do DBCC CHECKDB Repair Options function?

1. What is the purpose of repair?

Many of the users have misinterpretation that DBCC CHECKDB Repair fixes corruption. However, what this option does it makes the database structurally proficient so that the storage engine can run the database with facing any corruption. It fixes the error as soon as possible that why repair options in REPAIR_ALLOW_DATA_LOSS attempt to make the database stable, in process file needed to be repaired are deleted.

2. How does DBCC CHECKDB Repair figure what to repair?

At every step of processing, it creates a list of corruptions that are found and afterward it processes that corruption.

3. How does DBCC CHECKDB Repair choose what to repair first?

Every corruption has its own ranking based on how intense repair is required and the most corrupted files are repaired first. Meanwhile, the small problems are crossed off the list.

4. Does repair everything?

For that, you need to check the Output result. At the end of the output, if the number of errors found and the number of errors fixed are the same, it will think everything is fixed. But you need to be careful as oftentimes a corruption can hide another corruption. Or a corruption can restrict DBCC CHECKDB scanning that section of the database and repairing that corruption.

5. Why can’t DBCC CHECKDB be done online?

Fixing corruption online is not an option because copying data online and fixing corruptions contradicts the nature of the repairing process.

 Also Read: Fix Database Consistency and Integrity Error in SQL Server

What are the DBCC CHECKDB Repair Options

To know which options are best to repair, you need to run DBCC CHECKDB and it will reveal you which the repair option is essential. Here I have listed various repair options:

1. REPAIR_FAST

Exist for backward compatibility purposes only.

2. REPAIR_REBUILD
Repair files without any data loss and better for the manual rebuild index.

3. REPAIR_ALLOW_DATA_LOSS

Repair those files are likely to suffer data loss.

Watch Out of REPAIR_ALLOW_DATA_LOSS
This option fixes any corruption by de-allocating what is damaged and fixing all the links which are either damaged or to be damaged. It behaves in such ways because it is the fastest and most capable to fix almost all the errors.

1. Things it does not take into account:

• Foreign-key restrictions and duplication.
• Inherent business intelligence and data relationships.

2. Create a backup and check duplication topologies.

3. After running the process check the data.

• Run DBCC CHECKDB twice to be sure about all corruptions were repaired properly and start again if any duplication is involved.
• Run DBCC CHECKCONSTRAINTS if required.

Misconceptions people have about Repair

Repair does not cause any kind of data loss, whereas, in reality, it depends on the level of corruption.
In case of corruption should be run as the default. Please do not do that.
You can fix corruption without using DBCC CHECKDB, let me clarify that you need to run DBCC CHECKDB to know about the corruption.
Running DBCC CHECKDB can fix all errors.
It is safe to perform repair on the system database.
Corruption can be fixed online.
REPAIR_REBUILD fixes everything.

What to do when DBCC CHECKDB Repair Allow Data Loss is Not working

Try using a Third Party tool

This SQL database repair software is a flawless answer for all SQL database corruption errors. You can use this tool to repair corrupted MDF and NDF files with a few clicks only. It is a highly accurate tool which can recover tables, views, triggers, default, programmability, and other functions easily. It’s dual recovery modes helps for deep scanning and recovering all the files without any data loss. You can also save your recovered data in SQL scripts using this tool. You can try this using trial version and see yourself how well this tool performs in a critical situation.

Conclusion

As we know every SQL DBA faces corruption once every now and then and you can handle them using DBCC CHECKDB Repair Options or an authentic third-party tool. So it is totally up to you how you want to fix your corruption. I hope this blog will be helpful to you.

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