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SQL Server stores data in MDF/LDF files. If a transaction is interrupted due to hardware or software failure during SQL Server operation, it may result in incomplete transactions and subsequent errors or inaccessible tables. In such cases, running the DBCC CHECKDB command can assess the database’s health. If the database couldn’t complete the transaction and is in a deferred state, it will generate an error message like this:
Msg 7929, Level 16, State 1, Line 1
Check Statement aborted. Database contains deferred transactions
A deferred transaction is an incomplete transaction that failed to finish the roll-forward process. In enterprise SQL servers, it arises from a high transaction volume, while in other editions, it manifests as a startup error. This issue occurs due to input-output errors, preventing the necessary page reading for the transaction.
If the SQL Server is suddenly started or stopped, it halts the transaction roll-forward process, hindering data retrieval from the table. Additionally, a deferred transaction can occur when a restore process is partially completed, stopping at a point where offline data is needed, necessitating a rollback.
Error 7929 occurs due to a deferred transaction. Resolving the transaction will automatically eliminate the error. Here’s a detailed guide on how to fix it:
NOTE: You cannot recover a defunct filegroup.
Now run the repair command DBCC REPAIR_ALLOW_DATA_LOSS for the database along with DBCC CHECKDB.
NOTE: The repair command deallocates the corrupt pages and allows to recover deleted records in the SQL Server and achieves a consistent state. However, executing this command might lead to significant data loss, which may be unrecoverable. It’s advisable to resort to this method only when other alternatives have failed.
If you encounter an error preventing database access and manual recovery poses risks, consider utilizing Kernel SQL Database Recovery tool It doesn’t require a backup file for database recovery. This SQL Recovery tool can access MDF/LDF files and eliminate errors, ensuring the database is restored to full health.
Here is the total procedure of recovering the data from a corrupt SQL database file –
Kernel SQL Database Recovery software is a lightweight and streamlined tool capable of accessing SQL databases across various versions and eliminating corruption or errors. It prevents the need for manual troubleshooting, reducing the risk of accidental data deletion.