Oracle Wait Interface: A Practical Guide to Performance Diagnostics & Tuning
by Richmond Shee, Kirtikumar Deshpande, K Gopalakrishnan
What Is a Wait Event?
An event can be defined as a particular function, or task, that the Oracle kernel performs on behalf of the user session or its own background process. Tasks such as reading and writing data blocks to and from data files, waiting for latch acquisitions before accessing or manipulating data in the memory, interprocess postings and communications, and so on are known as database events, and they have specific names.
But why are these events called wait events?
Every session that is connected to an Oracle instance needs resources to perform its tasks. A resource may be a data buffer, a latch, an enqueue (lock), a pin, or a database object. Whenever a session has to wait for something, the wait time is tracked and charged to ...
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