V$WAITSTAT

V$WAITSTAT displays block contention statistics. This table is only updated when timed statistics are enabled.

Column	Datatype	Description
CLASS	VARCHAR2(18)	Class of the block
COUNT	NUMBER	Number of waits by this OPERATION for this CLASS of block
TIME	NUMBER	Sum of all wait times for all the waits by this OPERATION for this CLASS of block

Note:

1.

select * from V$WAITSTAT;

CLASS	COUNT	TIME
data block	847238	382988
sort block	0	0
save undo block	0	0
segment header	1635	245
save undo header	0	0
free list	0	0
extent map	0	0
1st level bmb	31	23
2nd level bmb	24	14
3rd level bmb	0	0
bitmap block	0	0
bitmap index block	0	0
file header block	1116	17
unused	0	0
system undo header	0	0
system undo block	0	0
undo header	4604	133
undo block	701312	21200

Oracle data dictionary views

Oracle dynamic performance views