We have been troubleshooting severe performance problems all day, on a busy web application that uses SQL server 2008 R2. The database is 120 GB. In order to try to reproduce the problem in the test / dev environment we took a full backup of the database using Management studio.

The strange thing is ... after we did the backup ... the performance issues are gone!

We have since figured out that no full backup has been run for over 1 month and no maintenance jobs are scheduled on the SQL server The recovery mode is set to Simple

My question is: I you don't ever perform a full backup. Can that give performance issues? I am thinking about that the transaction log is never commited.

or is this just pure coincidence?