Delayed commits determine the rate of response a database provides to a COMMIT statement.
When the rate of committed changes to a database is high, the rate of transaction log writes can be the single largest factor in determining overall database performance. If you are trying to improve transaction log performance, you can set the delayed_commits option to On. When set to On, the database server replies to a COMMIT statement immediately instead of waiting until the transaction log entry for the COMMIT has been written to disk. When set to Off, the application must wait until the COMMIT is written to disk. Turning on the delayed_commits option results in fewer transaction log writes by avoiding multiple re-writes of partially filled log pages, and you can set the option per connection or for all connections. When the delayed_commits option is turned on, there is a risk that committed operations may be lost if the server goes down before the transaction log pages are flushed to disk.