122. You received complaints about the degradation of SQL query performance. You identified top SQL queries that consume time. What would be your next step to find out recommendations about statistics collection and restructuring of the SQL statement to improve query performance?
A) run Segment Advisor
B) run SQL Tuning Advisor on top SQL statements
C) run the Automatic Workload Repository (AWR) report
D) run the Automatic Database Diagnostic Monitor (ADDM) on top SQL statements
答案：B
当你发现sql执行慢等sql问题时，你使用top sql发现耗费时间的sql语句。这是你需要使用SQL Tuning Advisor推荐数据收集和重建sql语句。
可以使用 SQL 优化指导分析 SQL 语句，并获得性能建议案。通常，会将此指导作为ADDM 性能判断工具来运行。
Editor’s note: ADDM is like awr,it is using for monitor sql for system.not for top sql.
awr:auto workload repository ,体系的核心,statspack 的进一步改进(不收集操作系统信息，没有db time等),awr属于sys用户,存在sysaux表空间上,每1小时收集一次,在磁盘上保留7天select * from dba_hist_wr_control
addm:auto database diagonstic(诊断) monitor 提供建议
来自 “ ITPUB博客 ” ，链接：https://blog.itpub.net/11312660/viewspace-718624/ ，如需转载，请注明出处，否则将追究法律责任。
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