The SQL server is extremely effective at storing all the databases properly. But sometimes the SQL server itself goes through complications that need to be fixed as soon as possible. When the users don’t shut down the SQL server database properly, the SQL server enters a crash recovery mode so that the system can ensure the database remains consistent. When the SQL server enters the recovery mode, it goes through three different types of phases where each phase repairs different types of errors and issues. These states are highly dependent on the severity of the damage, which includes online state, suspect state, and recovery pending state.
During the online state, the users can still access the SQL server database when the data items get corrupted while performing a query. During the suspect state, you won’t be able to access the database easily while the SQL server database is present in the recovery mode. During the recovery pending state, the SQL server database checks for progress.
What are the Various Stages of SQL Server Database Recovery?
If you want to recover a SQL Server database from corruption, it will need a database administrator who can restore the backup of the SQL server in a meaningful and logical sequence. While moving the SQL server effectively from recovery mode to the normal mode, the data file, database, and data page will be recovered and restored from the supporting data. The recovery process consists of three phases.
Analysis Phase
This phrase will analyze the transactional log of the SQL server thoroughly. Not to mention, this phrase will also determine the last checkpoint and develop an ATT and DPT. ATT will contain the record of the entire active transactional log when the SQL server database is not shut down properly. On the other hand, the DPT contains all the records of the dirty pages that will indicate when the SQL server database was shut down.
Redo Phase
During this phase, the modifications that are recorded in the log will be forwarded while shutting the SQL server database down. During this phase, you won’t be able to write the data files. The DPT comes with minLSN or minimum log sequence that is extremely important to recover the SQ; server database successfully. This will also help you initiate the redo operation that is needed to support the dirty pages.
Undo Phase
This phase contains all the incomplete transactions that can be found in ATT while also ensuring proper preservation of the SQL server database. After a proper rollback, the SQL database will come back online where you need to implement no additional transaction log as per the database.
Why Does the SQL Server Database Enter the Recovery Mode?
To repair the issues, you always need to search for the root causes behind the problem. There are various causes behind the SQL server database recovery mode. Apart from the improper shutdown of the SQL server database, hardware failure is something that can also force the SQL server database to enter recovery mode.
The insufficient space in the hard disk is another common reason behind the recovery mode of the SQL server database. The corrupted database of the SQL server will undoubtedly cause many problems for the users. Here are some other reasons that can force the SQL server database to enter the recovery mode:
- Long-running transactions that might cause disruption.
- Overgrown size of the transactional log file.
- Existence of different VLFs inside the database transaction log.
- Bug in the SQL server.
How Can You Fix the SQL Server in Recovery Mode Issue?
Make sure that there is a sufficient amount of backup of the SQL server and the database during the recovery progress while you start the process. As per Rubrik, data backup is extremely important. When you troubleshoot the SQL server, you need to conduct a detailed and thorough investigation of the SQL server database so that you can find the error log. There are various ways you can fix the SQL server in recovery mode problem.
Forceful Repair
This repair option will undoubtedly help you fix this issue. MS developers always ask the users to create a backup of the data files as their primary method to recover and restore the errors that are reported in DBCC CHECKDB.
The repair options in the DBCC CHECKDB make the SQL server database ultimately recoverable. Make sure you always implement the CHECKDB with the other repair options so that you can achieve success with the repair options without any problem.
After you reactivated the multiple user modes and ran the DBCC CHECKDB with the REPAIR-BUIL, the SQL server database will be recovered. Make sure the backup is appropriate or you might end up losing the essential data items.
Detach and Reattach SQL Server Database
You can also use this method to convert the SQL server database from recovery mode to normal mode. This mode will enable the database to enter emergency mode. Once the SQL server database becomes accessible again, you just need to take it offline and then online.
Conclusion
This is how you can troubleshoot the SQL server in recovery mode. Do you have any other questions? Make sure you comment below to let us know.
