1.频繁commit或者rollback
无伴生
AWR看Key Instance Activity Stats
该图表示，总提交123w次，平均每秒339次
2.IO缓慢
伴生log file parallel write等待事件
可能是io紧张，导致lgwr写的慢，也可以去看lgwr的trc日志，20ms以下是正常的
根据snap_id分时间，测io的平均、峰值、等待。看峰值
SELECT
TO_CHAR(s.END_INTERVAL_TIME, 'YYYY-MM-DD HH24:MI') AS end_time,
s.instance_number,
ms.metric_name,
ROUND(ms.average, 2) AS avg_value,
ROUND(ms.maxval, 2) AS max_value,
ROUND(ms.minval, 2) AS min_value
FROM
dba_hist_sysmetric_summary ms,
dba_hist_snapshot s
WHERE
ms.snap_id = s.snap_id
AND ms.dbid = s.dbid
AND ms.instance_number = s.instance_number
AND ms.metric_name IN ('Physical Read Total IO Requests Per Sec', 'Physical Write Total IO Requests Per Sec', 'Physical Read Total Bytes Per Sec', 'Physical Write Total Bytes Per Sec')
AND s.END_INTERVAL_TIME BETWEEN TO_DATE('2025-03-01 00:00:00', 'YYYY-MM-DD HH24:MI:SS') AND TO_DATE('2025-03-31 23:59:59', 'YYYY-MM-DD HH24:MI:SS')
ORDER BY
s.END_INTERVAL_TIME;
3.过大的日志缓冲区(Log Buffer)
4.CPU负载高。
无伴生
5.RAC私有网络性能差,导致LMS同步commit SCN慢
伴生gc等待事件
6.控制文件争用
（rman频繁、asm控制文件的具体磁盘io满、v$视图频繁、控制文件过大）
伴生control file sequential read
AWR看IOStat by Filetype summary
7.bug（11203）(Doc ID 13074706.8)
