My Crusade

V$SYSTEM_EVENT视图
V$SYSTEM_EVENT视图显示了数据库实例（instance）启动以来所有会话（session）所遇到的所有等待事件的累计统计信息（aggregated statistics）。
SQL> desc v$system_event
Name                                      Null?    Type
—————————————– ——– —————————-
EVENT                                              VARCHAR2(64)
TOTAL_WAITS                                  NUMBER
TOTAL_TIMEOUTS                            NUMBER
TIME_WAITED                                   NUMBER
AVERAGE_WAIT                                 NUMBER
TIME_WAITED_MICRO                       NUMBER
TOTAL_WAITS_FG                              NUMBER
TOTAL_TIMEOUTS_FG                        NUMBER
TIME_WAITED_FG                               NUMBER
AVERAGE_WAIT_FG                            NUMBER
TIME_WAITED_MICRO_FG                   NUMBER
EVENT_ID                                           NUMBER
WAIT_CLASS_ID                                  NUMBER
WAIT_CLASS#                                      NUMBER
WAIT_CLASS                                       VARCHAR2(64)
其中EVENT列包含了等待事件的名称，TOTAL_WAITS列包含了会话等待该事件的次数。TIME_WAITED显示了等待该事件所花费的总时间。
V$SESSION_EVENT视图
V$SESSION_EVENT视图显示了当前连接到实例上的所有会话的等待事件的累计统计信息。
SQL> desc v$session_event
Name                                      Null?    Type
—————————————–
SID                                                   NUMBER
EVENT                                              VARCHAR2(64)
TOTAL_WAITS                                  NUMBER
TOTAL_TIMEOUTS                            NUMBER
TIME_WAITED                                   NUMBER
AVERAGE_WAIT                                 NUMBER
MAX_WAIT                                         NUMBER
TIME_WAITED_MICRO                        NUMBER
EVENT_ID                                          NUMBER
WAIT_CLASS_ID                                 NUMBER
WAIT_CLASS#                                     NUMBER
WAIT_CLASS                                      VARCHAR2(64)

Oracle OpenWorld 2008 will be held from September 21 to September 25 in San Francisco. And here is the agenda.
This year, there are 4 members of our group (in OARDC Shenzhen) have the opportuinity to participate this world’s largest conference for Oracle customers and technologists. But for me, I think I have to wait for [...]

A Data Guard configuration consists of one production database and one or more standby databases. The database in a Data Guard configuration are connected by Oracle Net and may be dispersed geographically. There are no restrictions on where the databases are located, provided they can communicate with each other.
You can manage primary and standby databases [...]