V$SYSTEM_WAIT_CLASS

Oracle 11gR1

V$SYSTEM_WAIT_CLASS displays the instance-wide time totals for each registered wait class.

Column	Datatype	Description
WAIT_CLASS_ID	NUMBER	Identifier of the wait class
WAIT_CLASS#	NUMBER	Number of the wait class
WAIT_CLASS	VARCHAR2(64)	Name of the wait class
TOTAL_WAITS	NUMBER	Number of times waits of the class occurred
TIME_WAITED	NUMBER	Amount of time spent in the wait by all sessions in the instance
TOTAL_WAITS_FG	NUMBER	Number of times waits of the class occurred, in the foreground session
TIME_WAITED_FG	NUMBER	Amount of time spent in the wait, in the foreground session

Note:

1.

select * from V$SYSTEM_WAIT_CLASS where wait_class like '%I/O%';

WAIT_CLASS_ID	WAIT_CLASS#	WAIT_CLASS	TOTAL_WAITS	TIME_WAITED
1740759767	8	User I/O	513514014	287258245
4108307767	9	System I/O	268399846	44366878

Oracle dynamic performance views