Best Solutions to Repair Suspect Database in MS SQL Server

To repair Suspect database error in MS SQL 2005, 2008, 2012, 2014, 2016 and 2017 read this article to recover SQL Server database from Suspect mode.

What is Suspect Database Error?

Microsoft SQL Server serves as a storehouse for data that is needed for different software applications on a single system or across a network. Sometimes a user may face a situation where a database in the SQL Server instance currently under running state is marked as Suspect. This condition will lead to a failure in creating a connection with the database. Such a database which is tagged as Suspect can be accessed by removing the causes for this problem. The forthcoming article will discuss the causes for this problem to occur and the possible solutions to repair suspect database from SQL Server 2005, 2008, & 2012.

The error message shown to user is somewhat similar to the one given below

Starting up database ‘abc_d’.
Error: 9003, Severity: 17, State: 5.

The log scan number (189623:15:2) passed to log scan in database ‘abc_d’ is not valid.

The above-mentioned error shows that there is some corruption of the log file(.ldf) and does not adhere to the data file(.mdf). Other error messages can also be shown depending upon the cause due to which the database has been categorized as Suspect.

User queries help in getting a better idea about the problem and to recover SQL database.

“I am currently using SQL Server 2008 edition on my Windows 7 system and there are many applications of mine that are dependant on it. Recently I have been facing difficulties in connecting my applications to some of my Databases and they are being shown as Suspect. Kindly guide me to recover SQL database from Suspect mode.”

SQL Server Database Shown as Suspect: Possible Reasons

There are a number of reasons why SQL Server marks a particular Database as Suspect.
Some of these reasons are mentioned as follows

  • Corruption present in the SQL Server Database
  • Insufficient space available to SQL server to repair suspect database during startup.
  • The files of Database are in use by OS or other Backup software
  • Sudden SQL Server Shutdown, Hardware or Power Failure

There exist a number of techniques for solving the issue of Suspect SQL database and broadly they can be classified as Manual and Automated. The upcoming section will try and explain a Manual technique for achieving this goal.

Quick Tip: If you want to skip the tedious & complex manual approach then it is highly advised to use an automatic tool such as SQL Recovery to efficiently recover SQL database from Suspect mode

Repair Suspect Database Manually

Implement the steps given below to recover Suspect SQL Server Database and to access important data.

1. Bring Database in Emergency Mode using the following code

USE master
GO

ALTER DATABASE abc_d SET EMERGENCY
GO

2. Execute DBCC CHECKDB command.
This will scan and check the physical and logical integrity of objects present in the marked database

DBCC CHECKDB (abc_d )
GO

3. Bring the Database in Single Mode using the below-mentioned query

ALTER DATABASE abc_d SET SINGLE_USER WITH ROLLBACK IMMEDIATE
GO

4. After the Database is in Single Mode, execute the following code to repair suspect database

DBCC CHECKDB (abc_d, REPAIR_ALLOW_DATA_LOSS)
GO

5. Lastly, restore Multiple access to the database by executing the query

ALTER DATABASE abc_d SET MULTI_USER
GO

Repair Suspect Database by Manual Method: Shortcomings

  • Manual solution consumes a lot of the users’ time for SQL server suspect database repair
  • High risk of losing data forever during manual approach to recover SQL database from suspect mode
  • A Large number of queries to recover SQL database make it complex for non-technical users.
Conclusion

The Suspect database problem is a common issue faced by users of SQL Server database and it has various causes. There is a set of TSQL commands to overcome this error but it poses many issues during implementation. It is better to use automated tools designed specifically for this purpose to repair suspect database.

Learn How SQL Server Large Transaction Log Affect Performance

Whenever a user adds, delete, or edit any record in the SQL Server all the changes are maintained in the transaction log. In addition, the background process keeps on writing the each and every transaction in the log and to the database. After that, the transaction log is marked as written. There are two types of recovery model i.e. Simple and Full Recovery Model is used by the database in the SQL Server. However, if the database uses full recovery model all the written transaction logs are maintained in the log. Moreover, it becomes mandatory for the user to manage the transaction log file and take backup on the daily basis. In addition, the transaction log files are big enough if the full recovery model is used for the database. Apart from this, the Transaction logs in the SQL server are the always auto-growth and it is also advised not to turn off the auto-growth feature. Because it is helpful in the case of emergencies.

More About the SQL Server Transaction Log Size

The Transaction Log files in the SQL Server database is made up of one or more physical files and SQL Server writes to one physical transaction log file at a time. The internal structure of the physical files that is used by the SQL Server for transaction log files is known as Virtual Log Files (VLFs). However, the number and size of VLFs files inside the transaction log files directly depend on the number of factors. The size of VLFs files is determined at the time when the transaction log file is created or extended.

Effect of Large Transaction Log in SQL Server Performance

SQL Server transaction log file is comprised of small parts known as virtual log files whose size is not fixed. However, the main motive is to keep the small number of the virtual log files for the transaction log file. It is because SQL Server manages the smaller number of files more easily.

  • If there are a huge number of virtual log files then, there can be two possible reasons behind this. One is the small transaction log that has grown up (manually or automatically) in very small segments and another is a problematic situation where the large growth segments were configured but accidentally small VLFs were configured in the Transaction log. However, if the Virtual Log Files grows unnecessarily large due to auto growth, the logs become fragmented and may results in delay also. Moreover, it also slows down the recovery process that is why having so many or very little virtual log files results in bad performance.
  • Apart from all this, the auto-growth option is also offered, which is turned on by default. If the auto-growth settings are not handled in an appropriate manner, a SQL Server database will be forced to auto-grow that may lead to the serious performance issues. It is because the SQL Server will halt all processing until the auto-grow event is completed. However, the auto-growth event will take lots of space due to the physical organization of the hard drive that is not close physically to the previous one occupied by the transaction log file. This results in the physical fragmentation of the files that also causes slower response.
  • It is always suggested to backup the transaction logs regularly. However, if the backup process fails, then the log files will grow largely and left with over-sized transaction file. It is because old transaction logs are not removed which makes transaction logs increase at a rapid rate. If the SQL Server database is having a large transactions logs then, it has a bad effect on the performance of the SQL Server such as:
  1. If the transaction log file is full in the SQL Server database, it degrades the performance of the SQL Server.
  2. It also slows down the speed of the transactional log backup process.
  3. In addition, the over-sized transaction logs decrease the disk space also because old transaction logs are not removed yet.

How to Resolve Over-sized Transnational Log Problem?

The number of VLFs files is increased by an auto-grow event, that has a common process but requires strict rules to prevent the unplanned issues with space or unresponsiveness. Therefore, to reduce the bad effect of over-sized transaction log files on the performance of the SQL Server, it is necessary to resolve the issue.

The most common solution is that reduce the number of virtual log files in the transaction logs files. Now, to do the same follow the three simple steps discussed below:

  1. Backup the Transaction Log files.
  2. After that, shrink the transaction log files.

It is because the number of virtual log files in the transaction logs is reduced by shrinking the SQL Server transaction log file that needs strict rules also to avoid deleting the data that has not been backed up till now.

Conclusion

Transaction Log files are the most important log files in any SQL Server database, which grows always because the auto-growth option is turn on by default. The internal structure of the transaction log file has many virtual log files. However, if there are an excessive number of VLFs then, it has some bad effects on the performance of SQL Server. Therefore, it is necessary to properly control the auto-growth feature of the transaction log files.