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 |
