Oracle Wait Interface: A Practical Guide to Performance Diagnostics & Tuning

OWI Components

Oracle Wait Interface is a collection of a few dynamic performance views and an extended SQL trace file.

Oracle Wait Interface provides statistics for wait events to tell you how many times and how long the session waited for an event to complete. To get the “how long” part, however, you must set the initialization parameter, TIMED_STATISTICS, to TRUE. Old documentation associated high overhead with this parameter and scared a lot of DBAs away. But take comfort: these days, setting this parameter to TRUE does not add any appreciable overhead to the database performance on most platforms because most machines provide hardware support for fast timers. It provides critical and required timing information for all performance improvement ...