Tuesday, 18 September 2012

How to repair a Suspect Database in SQL Server

How to repair a Suspect Database in SQL Server


Introduction

There can be a possibility that when you connect to an SQL Server Instance you will find the database being marked as SUSPECT. During such scenarios, you will not be able to connect to the database. In this article we will go through the steps which you need to follow to recovery a database which is marked as SUSPECT. The steps mentioned in this article works on SQL Server 2005 and higher versions.

Some of the reasons why an SQL Server database can be marked as SUSPECT

  1. 1. Database could have been corrupted.
    2. There is not enough space available for the SQL Server to recover the database during startup.
    3. Database cannot be opened due to inaccessible files or insufficient memory or disk space.
    4. Database files are being held by operating system, third party backup software etc.
    5. Unexpected SQL Server Shutdown, Power failure or a Hardware failure.
Due to a hardware failure one of our database namely BPO was marked SUSPECT when the SQL Server came back online. Already due to the hardware failure we had downtime for more than two hours and adding to that when the server came back online our mostly critical database was marked as SUSPECT.

Steps to Recover a Database Marked as SUSPECT

1. Execute the below mentioned TSQL code to identify all the databases which are marked as SUSPECT.
USE master
GO


SELECT
 NAME,STATE_DESC FROM SYS.DATABASES
WHERE STATE_DESC='SUSPECT'GO
2. Open the latest SQL Server Error Log and check for errors logged for the database which is marked as suspect. You can open SQL Server Error Log by expanding Management Node à SQL Server Error Logs. In my server I could find below mentioned entries in SQL Server Error Logs.

Sample Error Messages within SQL Server Error Log when database is marked as SUSPECT
Starting up database 'BPO'.
Error: 9003, Severity: 20, State: 9.
The log scan number (189624:16:2) passed to log scan in database 'BPO' is not valid. This error may indicate data corruption or that the log file (.ldf) does not match the data file (.mdf). If this error occurred during replication, re-create the publication. Otherwise, restore from backup if the problem results in a failure during startup.
Error: 3414, Severity: 21, State: 1.
An error occurred during recovery, preventing the database 'BPO' (database ID 10) from restarting. Diagnose the recovery errors and fix them, or restore from a known good backup. If errors are not corrected or expected, contact Technical Support.
CHECKDB for database 'BPO' finished without errors on 2009-12-15 11:30:28.320 (local time). This is an informational message only; no user action is required.
3. When a database is in SUSPECT mode you will not be able to get connected to the database. Hence you need to bring the database first in EMERGENCY mode to repair the database. Execute the below mentioned TSQL code to bring the database in EMERGENCY mode.
USE master
GO
 
ALTER DATABASE BPO SET EMERGENCY
GO
Once the database is in EMERGENCY mode you will be able to query the database.