CAUSE
This warning message may be logged because the NO_LOG and TRUNCATE_ONLY options of the BACKUP statement truncate the transaction log files, and you might need transaction logs for the full recovery of the database.
MORE INFORMATION
You might see the message only when you have the database in full recovery mode, and you try to back up the transaction log by using either the NO_LOG or the TRUNCATE_ONLY options. You may not receive the error message when you do not have the database in full recovery mode, or when you do not use the NO_LOG or TRUNCATE_ONLY options when you back up the transaction log.
Note The NO_LOG or TRUNCATE_ONLY options truncate the transaction log. When you use these options, you might not receive a full database backup.
To view the SQL Server error log, you can use the sqldiag command prompt utility. The sqldiag utility gathers and stores both diagnostic information, and the contents of the query history trace (if running). By default, you might find the output file SQLDiag.txt in the following location:
:\Program Files\Microsoft SQL Server\MSSQL\LOG
The output file includes the text of all the SQL Server error logs.
For more information about how to use the sqldiag utility, visit the following Microsoft Web site:
sqldiag Utility
Steps to Reproduce the Behavior
To reproduce the behavior, follow these steps:
Open SQL Query Analyzer.
Create a new database, and name it test. For example:CREATE DATABASE test GO
Set the database recovery mode to FULL. For example:ALTER DATABASE test SET RECOVERY FULLGO
Create a new table and name it testtab in the database. Enter some data in testtab. For example:CREATE TABLE testtab( numbers int )GODECLARE @i intSET @i=1WHILE @i<=100BEGININSERT INTO testtab VALUES(@i)SET @i=@i+1ENDGO
Back up the database that is named test to a disk device. For example:BACKUP DATABASE test TO DISK = 'c:\Testdb.dmp'GO
Make a few changes to the table that is named testtab in the database that is named test.
For example, delete some rows from the table testtab:DELETE FROM testtab WHERE numbers<=10GO
Back up the transaction: BACKUP LOG test TO DISK = 'c:\Testlog.dmp'GO
Note Check the Application Log in Event Viewer. No error message appears for the backup.
Make some more changes to the data, and then back up the transaction log again by using the NO_LOG option. For example:DELETE FROM testtab WHERE numbers<=20BACKUP LOG test WITH NO_LOGGO
Note Check the Application Log in Event Viewer. You can find the error message for the backup.
Create a full database backup for the database that is named test:BACKUP DATABASE test TO DISK = 'c:\testdb.dmp'GO
Note Check the Application Log in Event Viewer. No error message appears for the backup.