Possible Reasons for Suspect Database and How to Fix It?

Daniel Jones | July 20th, 2017 | SQL, SQL Server Error |

SQL Server is a database creation and manipulation tool that is built by Microsoft. It is a relational database management system that stores and retrieves data as requested. The programming language used to handle this database server is called Structured Query Language. SQL is used to build large databases that can store data in a tabular form. Often there are multiple errors and bugs generated by the SQL Server. One such issue is the database going into Suspect Mode. This is a very tricky issue and cannot be solved by any manual methods. In this post, reasons for Suspect Database have been discussed. Also, possible ways to recover database from said mode have been described.

Probable Reasons for Suspect Database

During startup, SQL Server tries to obtain an exclusive lock on the important files of the server. This way no other application can access data from the database whenever the server is online. However, maybe sometimes these device files are being used by another process or are just missing. In such cases, errors are generated and the database goes into the suspect mode.

Following are some of the reasons behind a Suspect database:

  • The device or drive is inaccessible to the server where the server log files are kept. This can be caused by corruption in the hard drive sector or partition.
  • The files are missing and cannot be found. There can be many causes for Suspect database. Sometimes, a viral attack or any malicious malware may be deleting server files.
  • Another cause for suspect mode is due to a recent SQL server crash in the middle of the transaction. If a transaction is updating values for a relatively large database and it is stopped midway, there may be changes made to some value and not others. This may cause corruption in the transaction logs and errors are generated.
  • Some other application may be handling the server’s device files are preventing access to data files. This results in issues while opening a SQL server database and connecting to it. Most of the antivirus block certain files that they deem problematic. There might be some corruption in the file caused by a malware that scanners start to repair and fix.
  • Another one of the reasons for suspect database is corruption in transaction log caused due to improper shutdown of the local machine.
  • There may be errors generated due to limited disc space or physical drive of the computer.
  • Corruption in the LDF or MDF files of a SQL server.
  • There may be issues while rolling back or completing a transaction.
  • The data or log files are being held by another third-party application, some backup software or by the operating system itself.

How to Fix a Suspect Database?

There are different modes that define the state in which the database files are in currently. Separate procedures are implemented to work in each mode. There is an offline mode, online mode, data restoration mode, data recovery mode, emergency mode etc. Another one is the Suspect Mode. Going into said mode indicates an issue with the primary file group. After entering this mode, the database becomes inaccessible and data within it cannot be recovered. Alternative recovery procedures need to be implemented to be able to connect to the database. Some of the alternatives have been described below:

  • Enter the Emergency Mode to gain access to the SQL Server database. This mode gives a read-only access to the administrator to troubleshoot the database in case of an emergency.

    ALTER DATABASE database_name SET EMERGENCY
  • Having gained access to the database, run a Consistency Check on the master database file. This checks for all logical and physical errors within the database.

    DBCC CHECKDB (‘dbName’)
  • After that, switch to Single User Mode and rollback any transaction that might not have completed successfully.

    ALTER DATABASE dbName SET SINGLE_USER WITH ROLLBACK IMMEDIATE
  • Next, if errors are found during the DBCC check, then repair them using repair_rebuild, repair_allow_data_loss and repair_fast.

    DBCC CheckDB (‘dbName’, REPAIR_ALLOW_DATA_LOSS)
  • Finally, switch back to Multi User Mode and verify connectivity of database.

    ALTER DATABASE dbName SET MULTI_USER

Final Words

SQL Server is the most commonly used database management application to store and retrieve data. There are errors and issues encountered by many while using the database server. Some of them may be rectified using manual methods, other may not. One such issue is the Suspect Mode. Advanced SQL users find it difficulty to access data or connect to a database once it enters the suspect mode. In this post, are described possible reasons for suspect database. There a number of alternative solutions available in the market to recover database from suspect mode.

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