Does DBCC CHECKDB Fix Errors? Know the Facts

If you are a SQL database user, you must get different errors once in a while. And when you get these errors, you look for native solutions. One such popular command in DBCC CHECKDB. Its reputation and frequent usage often make users think that this command is the absolute solution to get rid of any SQL error. In order to confirm, people also ask, does DBCC CHECKDB fix errors on SQL database? Here, we take the opportunity to answer this common query. Besides, we will also discuss what does DBCC CHECKDB do, how long does the command take to repair and alternative to DBCC CHECKDB.

“Our SQL database became damaged in some way and therefore, users are facing different errors. Before trying some utilities, I would like to try the manual techniques to fix SQL database errors. Kindly tell me does DBCC CHECKDB fix errors? I will proceed with this method only after confirmation. I am looking for answers from subject-matter experts.”

What Does DBCC CHECKDB Do?

DBCC CHECKDB is a commonly used command that can check database consistency of SQL Server. Its main function is to inspect the physical (data files) and logical (log files) integrity of SQL database. The execution of this command will repair corrupt and damaged SQL Server database only to a certain level. If the SQL errors are caused by mild corruptions, DBCC CHECKDB
command can fix those errors.

How Long Does DBCC CHECKDB Take

People, who are interested to run this command, also like to know how long does this command take to fix errors. Well, there is no fixed time frame for this command. The total time taken by this command to perform depends on several things, such as:

The Amount of Data in Database: If you have a huge amount of data stored in your database, the command will take time to check and fix the database.

The Strength of the System: If the power of the server and/or I/O subsystem is not sufficient compared to the database complexity, DBCC CHECKDB will take more time than the usual.

Database Schema Complexity: If numerous features are used in a database, the CHECKDB command will take more time.

Database Corruptions: Depending on the severity of the database corruption, DBCC CHECKDB will take time to fix the errors.

Tempdb Database Configuration: DBCC CHECKDB uses tempdb database to save the data extracted while checking the intermediate consistency. Poorly configured tempdb database can cause the command to work slow.

How to Run DBCC CHECKDB Command in SQL Server

Now, we will learn about different DBCC CHECKDB commands that can be used to get rid of the inconsistencies of database. Depending on the corruptions, three types of DBCC CHECKDB commands are usually used for repairing database damages.
a) REPAIR_FAST: This command option manages syntax for backward database compatibility. Do not run this command to repair database as it cannot perform that function.

b) REPAIR_REBUILD: If you suspect that the database is having some minor corruptions, you can run this DBCC CHECKDB command. When your database requires quick repairing in situations such as index rebuilding and missing non-clustered index rows, this command is ideal. Remember that FILESTREAM data related errors cannot be fixed using this command. Since it deals with minor corruptions, data loss does not occur when it is implemented.

c) REPAIR_ALLOW_DATA_LOSS: This command can be applied only under certain circumstances. Only if your database is severely damaged and no last good backup of your database is available for restoration, this command should be used. The reason for this caution can be understood if we carefully check the name. The name itself says that by running this command, users are allowing data loss from their database. The command deleted all the corrupt data and retains only the healthy ones. Thus, it bears high chance of data loss while fixing the database errors.

Remember: Users should not consider REPAIR_ALLOW_DATA_LOSS command as a substitute to good database backup and restore.

Is There An Alternative to DBCC CHECKDB

DBCC CHECKDB REPAIR_ALLOW_DATA_LOSS command is not the most reliable solution to fix SQL database error. Hence, users search for an alternative to DBCC CHECKDB command. For data loss free SQL database repairing, users must opt for MDF Database Repair Tool. The advanced features of this software make any database completely corruption free. Even if some data have been deleted due to corruption, this software retrieves the deleted data too. This application can be utilized for repairing both MDF and NDF database files. The healthy database can be exported into live SQL database or as SQL compatible scripts. The tool is compatible with all the latest versions of SQL Server including SQL Server 2017.

Conclusion

The discussion of this write-up answers the question, does DBCC CHECKDB fix errors? We have explained that the functionality of this command in terms of fixing errors and corruption is limited. That is why, users often choose the alternative to DBCC CHECKDB, SQL Recovery Tool for fixing errors. This tool safely resolves the database corruption issues without losing any data.

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I am SQL DBA and SQL Server blogger too. I like to share about SQL Server and the problems related to it as well as their solution and also I do handle database related user queries, server or database maintenance, database management etc.

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