SQL Server log file too big

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

If it is, this may indicate a potential problem:

By the way, this check is a part of our SQL Server Health Check service.

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

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

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?

Read the details below for information on how to:

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


Microsoft – A transaction log grows unexpectedly or becomes full in SQL Server

Microsoft Manage the size of the transaction log file

Let our expert SQL Server Consulting team handle the technical complexities, so you can focus on driving your business forward with confidence.

Picture of Mark Varnas

Mark Varnas

Hey I'm Mark, one of the guys behind Red9. I make a living performance tuning SQL Servers and making them more stable. I channel my SQL into our SQL Managed Services, SQL Consulting and our internal database products.

One Response

  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.


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