wait等待事件及其处理方法：
1、db file sequential read
调整SQL,增加buffer cache,加快磁盘读写速度
2、log file sync
减少事务提交，将redo文件存放于高速硬盘
3、db file scattered read
FTS-调整SQL,增加索引，加快磁盘读写速度
4、latch free – need p1,p2,p3
5、enqueue – need p1,p2,p3 and SQL
6、SQL*Net more data from client
减少数据传输，网络优化
7、direct path read
排序问题，调整IO或者减少排序
8、direct path write
直接路径访问问题，加快磁盘读写速度
9、buffer busy waits – need p1,p2,p3 and SQL
10.SQL*Net more data to client
减少数据传输，网络优化
11.log buffer space
加大log buffer
12.log file switch completion
加大log文件尺寸大小
13.library cache pin
减少相同游标的并发解析，比如绑定变量
14.SQL*Net break/reset to client
检查SQL语句是否出错
15.file open
减少log文件打开
16.free buffer waits
增加buffer cache size
17.db file parallel read
调整SQL，优化IO，加大buffer cache
18.write complete waits
增加buffer cache ，或者优化DBWR
20.library cache lock
避免同一时间进行硬解析
21.SQL*Net more data from dblink
减少数据传输，网络优化
22.log file switch (checkpoint incomplete)
增加log文件，或者调整加大log文件的大小
23.library cache load lock
避免同一时间cursor进行硬解析
24.row cache lock
need p1
25.local write wait
truncates / reduce cache size
降低cache size
26.sort segment request
SMON busy, process rollback problem
SMON进出繁忙，rollback问题
27.process startup
在MTS情况下，增加init.ORA文件中min servers and dispatchers参数
28.file identify
降低CHECKPOINTS，保持文件打开
29.pipe put
加快pipe管道读
30.switch logfile command
避免频繁进行log切换
31.SQL*Net break/reset to dblink
检查sql是否有误
32.log file switch (archiving needed)
归档空间不足
33.direct path write (lob)
优化IO，减少lob读写
34.undo segment extension
Use UNDO or with RBS, increase RBS size, avoid OPTIMAL
35.undo segment tx slot
Use UNDO, increae # of RBS segs
