SQL Server Tips

SQL Server Log File Too Big

Updated
2 min read
Written by
Mark Varnas

Log files are larger than data files

It is not common to have SQL Server log files larger than data files.

If it is, this may indicate a potential problem:

How to find databases with log files larger than database files?

You can use the script below. It will return all databases with log files (over 1GB) larger than the data file.

SELECT DB_NAME(a.database_id) AS DatabaseName
	,CAST((CAST(a.size AS BIGINT) * 8 / 1000000) AS NVARCHAR(20)) AS 'LogFileSize_GB'
FROM sys.master_files a
WHERE a.type = 1
	AND DB_NAME(a.database_id) > 4
	AND a.size > 125000 /* Size is measured in pages here, so this gets us log files over 1GB. */
	AND a.size > (
		SELECT SUM(CAST(b.size AS BIGINT))
		FROM sys.master_files b
		WHERE a.database_id = b.database_id
			AND b.type = 0
		)
	AND a.database_id IN (
		SELECT database_id
		FROM sys.databases
		WHERE source_database_id IS NULL
		)

How can I fix the issue?

To address the issue, follow the instructions provided below:

  1. Check if you are using the correct recovery model.
  2. Verify the maintenance plans.
  3. Shrink the transaction log file.

References:

Article by
Mark Varnas
Founder | CEO | SQL Veteran
Hey, I'm Mark, one of the guys behind Red9. I make a living performance tuning SQL Servers and making them more stable.

1 thought on “SQL Server Log File Too Big”

  1. Hey Jose,

    thanks for this script (even though a little buggy…). It helped point out some issues around recovery models and types of backups that were set up and what changes needed to be made.

    Cheers!

    Reply

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