|
wait等待事件及其处理方法 db file sequential read 调整SQL增加buffer cache加快磁盘读写速度 log file sync 减少事务提交将redo文件存放于高速硬盘 db file scattered read FTS调整SQL增加索引加快磁盘读写速度 latch free – need ppp enqueue – need ppp and SQL SQL*Net more data from client 减少数据传输网络优化 direct path read 排序问题调整IO或者减少排序 direct path write 直接路径访问问题加快磁盘读写速度 buffer busy waits – need ppp and SQL SQL*Net more data to client 减少数据传输网络优化 log buffer space 加大log buffer log file switch completion 加大log文件尺寸大小 library cache pin 减少相同游标的并发解析比如绑定变量 SQL*Net break/reset to client 检查SQL语句是否出错 file open 减少log文件打开 free buffer waits 增加buffer cache size db file parallel read 调整SQL优化IO加大buffer cache write complete waits 增加buffer cache 或者优化DBWR library cache lock 避免同一时间进行硬解析 SQL*Net more data from dblink 减少数据传输网络优化 log file switch （checkpoint incomplete） 增加log文件或者调整加大log文件的大小 library cache load lock 避免同一时间cursor进行硬解析 row cache lock need p local write wait truncates / reduce cache size 降低cache size sort segment request SMON busy process rollback problem SMON进出繁忙rollback问题 process startup 在MTS情况下增加initORA文件中min servers and dispatchers参数 file identify 降低CHECKPOINTS保持文件打开 pipe put 加快pipe管道读 switch logfile command 避免频繁进行log切换 SQL*Net break/reset to dblink 检查sql是否有误 log file switch （archiving needed） 归档空间不足 direct path write （lob） 优化IO减少lob读写 undo segment extension Use UNDO or with RBS increase RBS size avoid OPTIMAL undo segment tx slot Use UNDO increae # of RBS segs |
