Introduction
In a previous post, we explored five significant SQL Server error log messages that demand immediate attention. However, the SQL Server error log contains a wealth of additional information essential for maintaining the health and performance of your databases. In this sequel, we will highlight five more error log messages that should be on your radar. We’ll look into what each error means and offer suggestions for when you encounter them.
Five Additional SQL Server Error Messages to Watch Out For
Error 9002: Transaction Log Full
Example Message:
Msg 9002, Level 17, State 2, Line 1
The transaction log for database 'AdventureWorks' is full due to 'LOG_BACKUP'.Error 9002 occurs when the transaction log for a database becomes full and cannot accommodate new transactions. This situation can halt database operations and potentially lead to application failures or data loss. The most common cause is the lack of proper log backups, which prevents SQL Server from truncating the transaction log and reusing space.
When you encounter this error, your immediate response should be to perform a transaction log backup. This action frees up space within the log file by allowing SQL Server to truncate inactive portions of the log. Additionally, you should check the disk space where the transaction log resides to ensure there is sufficient room for it to grow if necessary.
It’s also important to investigate whether any long-running or uncommitted transactions are preventing the log from truncating. If such transactions exist, resolving them can help alleviate the issue. Adjusting the autogrowth settings for the transaction log file may also be beneficial, ensuring that SQL Server can automatically manage the file size as needed.
For further reading, visit Microsoft’s documentation on Error 9002.
Error 605: Page Not Found or Incorrect Page ID
Example Message:
Msg 605, Level 21, State 3, Line 1
Attempt to fetch logical page (1:1234) in database 'SalesDB' belongs to object 'unknown', not to object 'Orders'.Error 605 indicates that SQL Server has encountered a problem accessing a data page—it either cannot find the page or the page ID does not match the expected value. This error often signals database corruption, which can result from hardware failures, abrupt power losses, or issues with the storage subsystem.
Upon encountering this error, you should immediately run a full database consistency check using the DBCC CHECKDB command. This utility helps identify the extent of the corruption and whether it can be repaired. Reviewing the SQL Server error log and the Windows Event Viewer can provide additional context, such as hardware errors or system crashes that might have contributed to the problem.
If the corruption is severe and cannot be repaired, restoring the database from the most recent known good backup might be necessary. It’s also advisable to check your hardware components, such as disk drives and controllers, for any signs of failure or malfunction. Implementing preventative measures like regular backups and consistency checks can help avoid such issues in the future.
For further reading, visit Microsoft’s documentation on Error 605.
Error 701: Out of Memory
Example Message:
Msg 701, Level 17, State 123, Line 1
There is insufficient system memory in resource pool 'default' to run this query.Error 701 occurs when SQL Server cannot allocate enough memory to execute a query or perform an operation. This situation can arise due to memory-intensive queries, insufficient memory allocation to SQL Server, or memory leaks within the system.
To address this error, start by monitoring the current memory usage using tools like Performance Monitor or SQL Server’s Dynamic Management Views (DMVs). Identifying queries that consume large amounts of memory can help you optimize them for better efficiency. Adjusting the ‘max server memory’ setting in SQL Server ensures that it doesn’t consume all available system memory, leaving enough for the operating system and other applications.
If memory leaks are suspected, observe the memory consumption over time to detect unusual patterns. In some cases, adding more physical RAM to the server might be necessary to meet the demands of your workload.
For further reading, visit Microsoft’s documentation on Error 701.
Error 18456: Login Failed for User
Example Message:
Login failed for user 'Alice'. Reason: Password did not match that for the login provided. [Client: 203.0.113.42]Error 18456 is a general login failure error that occurs when a user cannot authenticate with SQL Server. The error message often includes a state code that provides more details about the failure’s cause, such as an incorrect password, a disabled login, or insufficient permissions.
When this error appears, first verify the credentials being used to ensure the username and password are correct. Check if the login account is locked, disabled, or has an expired password. It’s also important to confirm that the user has the necessary permissions to access the specific database they’re attempting to use.
Additionally, ensure that SQL Server is configured to accept the type of authentication being used—either Windows authentication, SQL Server authentication, or both. Reviewing the error logs can provide further insights, particularly the state code associated with the error.
It’s worth noting that although unlikely, excessive login failures could indicate an attempt to compromise the system. Monitoring repeated failed login attempts can help you identify potential security threats. Implementing account lockout policies and using strong passwords are effective measures to enhance security.
For further reading, visit Microsoft’s documentation on Error 18456.
Error 1450: Insufficient System Resources
Example Message:
Msg 1450, Level 16, State 1, Line 1
Insufficient system resources exist to complete the requested service.Error 1450 indicates that the operating system has run out of a system resource required to complete a SQL Server operation. This can occur due to limitations in disk space, memory, or other system resources.
To resolve this error, begin by checking the available disk space on the drives used by SQL Server. If disk space is low, consider deleting unnecessary files or expanding the storage capacity. Monitoring memory usage is also important, as insufficient memory can contribute to resource constraints. Adjusting system configurations or upgrading hardware may be necessary to ensure adequate resources are available.
Reviewing the Windows System and Application event logs can provide additional information about which resources are depleted. It’s also advisable to check for any recently installed applications or services that might be consuming excessive resources.
For further reading, visit Microsoft’s documentation on Error 1450.
Importance of Proactive Monitoring
While reacting promptly to error messages is essential, proactive monitoring can prevent many issues from occurring in the first place. Utilizing SQL Server’s built-in monitoring tools and setting up alerts for specific error conditions can help you address potential problems before they impact your database environment. Regularly reviewing performance metrics, disk space utilization, memory usage, and authentication attempts can provide valuable insights into the overall health of your SQL Server instances.
Conclusion
Understanding and responding to SQL Server error log messages like 9002, 605, 701, 18456, and 1450 is vital for maintaining a stable and efficient database environment. By taking appropriate action when these errors occur, you can minimize downtime, prevent data loss, and ensure that your applications continue to run smoothly. Remember, effective database administration combines reactive troubleshooting with proactive monitoring, enabling you to anticipate and mitigate issues before they escalate. Keep exploring SQL Server’s extensive logging and monitoring capabilities to enhance your database management strategies.