Oracle 动态视图4 V$SESSION_WAIT & V$SESSION_EVENT

一、视图V$SESSION_WAIT显示了session的当前等待事

Column	Datatype	Description
SID	NUMBER	Session identifier
SEQ#	NUMBER	Sequence number that uniquely identifies this wait. Incremented for each wait.
EVENT	VARCHAR2(64)	session当前等待的事件，或者最后一次等待事件
P1TEXT	VARCHAR2(64)	Description of the first additional parameter
P1	NUMBER	First additional parameter
P1RAW	RAW(4)	First additional parameter
P2TEXT	VARCHAR2(64)	Description of the second additional parameter
P2	NUMBER	Second additional parameter
P2RAW	RAW(4)	Second additional parameter
P3TEXT	VARCHAR2(64)	Description of the third additional parameter
P3	NUMBER	Third additional parameter
P3RAW	RAW(4)	Third additional parameter
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
WAIT_TIME	NUMBER	WAIT_TIME <> 0  上次实际等待时间；WAIT_TIME=0  session正在等待当前的事件
SECONDS_IN_WAIT	NUMBER	WAIT_TIME=0  SECONDS_IN_WAIT是在当前等待条件下的等待时间； WAIT_TIME>0  SECONDS_IN_WAIT是指从上次等待的起始时间到当前时间，SECONDS_IN_WAIT - WAIT_TIME /100 是从上次等待结束时间点到当前时间(即活动时间)
STATE	VARCHAR2(19)	Wait state:
		0 - WAITING (session正在等待当前的事件)
		-2 - WAITED UNKNOWN TIME (duration of last wait is unknown)
		-1 - WAITED SHORT TIME (last wait <1/100th of a second)
		>0 - WAITED KNOWN TIME (WAIT_TIME = 上次实际等待时间)

二、视图V$SESSION_EVENT记录了session自启动起所有的事件

Column	Datatype	Description
SID	NUMBER	ID of the session
EVENT	VARCHAR2(64)	Name of the wait event
TOTAL_WAITS	NUMBER	此session当前事件的总等待数
TOTAL_TIMEOUTS	NUMBER	等待超时次数
TIME_WAITED	NUMBER	此session总等待时间(单位，百分之一秒)
AVERAGE_WAIT	NUMBER	此session当前事件平均等待时间(单位，百分之一秒)
MAX_WAIT	NUMBER	Maximum time waited for the event by the session (in hundredths of a second)
TIME_WAITED_MICRO	NUMBER	Total amount of time waited for the event by the session (in microseconds)
EVENT_ID	NUMBER	Identifier of the wait event
WAIT_CLASS_ID	NUMBER	Identifier of the class of the wait event
WAIT_CLASS#	NUMBER	Number of the class of the wait event
WAIT_CLASS	VARCHAR2(64)	Name of the class of the wait event