It’s time for T-SQL Tuesday again, and I’m happy to participate again. This is a monthly blog party started by Adam Machanic (Blog|Twitter )that asks people to write on a particular topic all on the same day.
This month’s theme is misconceptions in SQL Server, hosted by Sankar Reddy. You can read the rules for the party and get information from his blog.
The Most Common Misconception
I read a lot of forum posts, literally hundreds a week on all topics in SQL Server. One thing that I consistently see asked is the dreaded:
“My transaction log has grown so large it filled the disk”
That’s a common occurrence, too common in my opinion, and while there are people that forget to setup any backups, I also find in the majority of cases people just don’t understand one thing:
A full backup does not clear the transaction log.
Too many people assume that the log will get managed by a full backup. It doesn’t. While some log record get included in a full backup, they do not get marked as “backed up” and the space re-used.
If there is one thing that I wish everyone managing a SQL Server knew, it would be that they need to make full and log backups to properly manage the disk space usage by their logs.