创建 AWR 快照并生成两个快照之间的 AWR 报告

命令

-- 1) Manual snapshot before and after the event (run in CDB root):
EXEC DBMS_WORKLOAD_REPOSITORY.CREATE_SNAPSHOT;

-- 2) List snapshots:
SELECT snap_id,
       TO_CHAR(begin_interval_time,'YYYY-MM-DD HH24:MI') AS begin_time,
       TO_CHAR(end_interval_time,'YYYY-MM-DD HH24:MI')   AS end_time
FROM   dba_hist_snapshot
WHERE  dbid = (SELECT dbid FROM v$database)
ORDER  BY snap_id DESC
FETCH FIRST 24 ROWS ONLY;

-- 3a) Interactive report (prompts for HTML/TEXT and snapshot range):
-- @?/rdbms/admin/awrrpt.sql      (RAC: awrgrpt.sql, specific instance: awrrpti.sql)

-- 3b) TEXT report from a script:
SET LINESIZE 8000 PAGESIZE 0 TRIMSPOOL ON HEADING OFF FEEDBACK OFF
SPOOL /tmp/awr_<begin_snap>_<end_snap>.txt
SELECT output
FROM   TABLE(DBMS_WORKLOAD_REPOSITORY.AWR_REPORT_TEXT(
         l_dbid     => (SELECT dbid FROM v$database),
         l_inst_num => (SELECT instance_number FROM v$instance),
         l_bid      => <begin_snap>,
         l_eid      => <end_snap>));
SPOOL OFF
-- For HTML: DBMS_WORKLOAD_REPOSITORY.AWR_REPORT_HTML (same parameters)

作用

生成覆盖问题时间窗口的两个 AWR 快照之间的报告：负载概况、Top 等待事件、Top SQL 和实例统计信息。表函数可让你从脚本或调度作业中获取报告。

适用场景

分析特定时间窗口内的性能下降、负载测试或批处理前后对比，以及容量报告时。

注意

需要 Diagnostics Pack 许可（CONTROL_MANAGEMENT_PACK_ACCESS='DIAGNOSTIC' 或 'DIAGNOSTIC+TUNING'）；没有许可时，将该参数设为 'NONE' 并使用 Statspack。报告不能跨越实例重启。超过一小时的范围会被平均化并掩盖短时尖峰；请保持窗口紧凑。