Live Chat
Home » Blog » SQL Server » Know About Repair_Allow_Data_Loss & Repair_Rebuild
SQL Server

Know About Repair_Allow_Data_Loss & Repair_Rebuild

Published By Mohit Jha
Tej Pratap Shukla
Approved By Tej Pratap Shukla
Published On November 27th, 2018
Reading Time 4 Minutes Reading

Like any other database, the SQL Server Database is the popular one. However, managing a large size database sometimes become an issue for the SQL Server administrator. As it keeps on generating inconsistency and integrity issues in the database time to time. Thus, to be consistent always, they need a proactive and fast problem solving measure.

The DBCCCHECKDB is one such popular command used by the SQL Database Administrator. It let them check any type of issue either it is inconsistency or integrity issue related to the database. Moreover, an administrator can keep backup of a database to overcome all type of corruption issues. Whenever a user runs DBCC CHECKDB command and it reports an issue, it offers one repair option also i.e., repair_fast, repair_allow_data_loss, and repair_rebuild.

However, repair_allow_data_loss, and repair_rebuild options are the two most common options provided by the DBCC CHECKDB. In most of the cases, a user can repair corrupt SQL database very easily but there are high chances of data loss in it. Thus, users are looking for proper information about these DBCC CHECKDB repair options i.e., repair_rebuild SQL database and repair_allow_data_loss commands. To know how these two commands actually work and is there any way to repair SQL database without any loss of data continue reading a blog.

Consider some of the common queries asked by the users:

“Yesterday, I was performing a consistency check on my database and it reported an error. After that, it suggested me to run repair_rebuild SQL database as a repair option. I do not know what exactly it was trying to do. I was not sure about it and do not want to put my database at risk so, I decided to do more search on it. This is the reason, why I am here. If any SQL expert is there, please help me out for the same.”

“I executed the Repair_rebuild command on my SQL database, it is taking a lot of time as it is still in execution. My database is large in size, is this delay because of that only? I am very confused and unable to understand the concept. What exactly is going on, can anyone tell me that? It will be a great help.”

Repair_Allow_Data_Loss & Repair_Rebuild Command in SQL Database?

Both of these commands are actually the repair options offered by DBCC CHECKDB. But both of them are very much different from each other and used in different terms and conditions. In order to know about them, go through the section given below:


If a user wants to repair SQL database without any loss of information, then this repair option is selected. This repair_rebuild command can be used in two ways:

  • Quick Repair: It will help in repairing absent rows in non-clustered indexes.
  • Normal Repair: In the time-consuming repair option, it will rebuild the indexes.

Note: This command will not repair any error involved in the FILESTREAM data.


In some cases users take help of repair_allow_data_loss command to repair all type of errors in the SQL database. It is pretty much clear from the name that there might be some loss of data during the recovery process. This means this DBCC CHECKDB command does not promise data integrity. Whenever this command is executed, it displays some messages also to warn the users like it leaves data in an inconsistent state. Thus, it is always suggested to create replicas of the MDF, NDF, and LDF files before running these commands.

Point to Remember: While using any of these repair option, make sure that particular database is in a single-user mode.

Better Option Over Repair_Rebuild SQL Database

As discussed above, DBCC CHECKDB repair options either Repair_allow_data_loss or repair_rebuild is not a feasible approach. Thus, users are recommended to switch to some third-party tool and get over of all corruption issues in the SQL database.

Among all available tools, SQL Database Recovery tool is the most popular one. It let users repair SQL database in a proper manner compared to repair_rebuild like manual commands. The software is capable enough to repair MDF and NDF files of SQL database in no time. Moreover, the application supports the recovery of database file from any SQL Server version.


The blog discusses what repair_allow_data_loss and repair_rebuild is. It covers the better option to opt over this repair commands in SQL Server database.


By Mohit Jha

Mohit is a Microsoft-certified expert who has assisted thousands of clients with Outlook & Microsoft Office 365 issues. He enjoys writing on email clients as well as data migration. He is always excited about giving troubled readers the most up-to-date knowledge, explanation, and refinements.