
196 7.3 Tools for Tuning Queries
Note: The IDLEEVENT function filters events on the V$SESSION_
WAIT view.
A faster result is possible for the above query by joining DBA_
EXTENTS.FILE_ID and DBA_EXTENTS.BLOCK_ID, retrieving only
wait events for extent headers as follows:
sw.block_id BETWEEN de.block_id AND de.block_id + blocks -1
Idle Events
An idle event is idle because nothing is happening. An idle event is a result
of a process that is busy waiting for something else to respond. Idle events
are generally insignificant as far as performance is concerned, although they
can sometimes show a distinct lack of activity, a lack of use of resources or
simply over ...