While including background process service and queue time is important and useful when analyzing an entire system, it can become less useful when focused on a single or a few sessions or processes. This normally does not present a problem, because session-focused collection will naturally include only time related to a specific session or group of sessions. So, what may seem like quite a technical challenge turns out to be not that big of a deal.

Depending on the Oracle release, Statspack and AWR reports may separate background process time. This makes our job even easier. But if the time is not separated, simply manually exclude any background process-related time.

When gathering data using your own scripts, remember to make the appropriate adjustments. The significant time-consuming background process wait events should be of no surprise: log file parallel write and db file parallel write. There are others, of course, but these are the most common. The other wait events are easily recognizable by their event name being associated with a background process. If you are unsure, refer to Oracle documentation or search Metalink. Even better, sample from v$session_wait or, for Oracle Database 10g and later, sample from v$active_session_history or v$session, to see which sessions are posting the wait event in question.