以下脚本可以用于列出最近Oracle数据库每小时估算的redo重做日志产生量,因为估算数据来源于archivelog的产生量和大小,所以数据是近似值,可供参考:
WITH times AS (SELECT /*+ MATERIALIZE */ hour_end_time FROM (SELECT (TRUNC(SYSDATE, 'HH') + (2 / 24)) - (ROWNUM / 24) hour_end_time FROM DUAL CONNECT BY ROWNUM <= (1 * 24) + 3), v$database WHERE log_mode = 'ARCHIVELOG') SELECT hour_end_time, NVL(ROUND(SUM(size_mb), 3), 0) size_mb, i.instance_name FROM( SELECT hour_end_time, CASE WHEN(hour_end_time - (1 / 24)) > lag_next_time THEN(next_time + (1 / 24) - hour_end_time) * (size_mb / (next_time - lag_next_time)) ELSE 0 END + CASE WHEN hour_end_time < lead_next_time THEN(hour_end_time - next_time) * (lead_size_mb / (lead_next_time - next_time)) ELSE 0 END + CASE WHEN lag_next_time > (hour_end_time - (1 / 24)) THEN size_mb ELSE 0 END + CASE WHEN next_time IS NULL THEN(1 / 24) * LAST_VALUE(CASE WHEN next_time IS NOT NULL AND lag_next_time IS NULL THEN 0 ELSE(size_mb / (next_time - lag_next_time)) END IGNORE NULLS) OVER( ORDER BY hour_end_time DESC, next_time DESC) ELSE 0 END size_mb FROM( SELECT t.hour_end_time, arc.next_time, arc.lag_next_time, LEAD(arc.next_time) OVER( ORDER BY arc.next_time ASC) lead_next_time, arc.size_mb, LEAD(arc.size_mb) OVER( ORDER BY arc.next_time ASC) lead_size_mb FROM times t,( SELECT next_time, size_mb, LAG(next_time) OVER( ORDER BY next_time) lag_next_time FROM( SELECT next_time, SUM(size_mb) size_mb FROM( SELECT DISTINCT a.sequence#, a.next_time, ROUND(a.blocks * a.block_size / 1024 / 1024) size_mb FROM v$archived_log a,( SELECT /*+ no_merge */ CASE WHEN TO_NUMBER(pt.VALUE) = 0 THEN 1 ELSE TO_NUMBER(pt.VALUE) END VALUE FROM v$parameter pt WHERE pt.name = 'thread') pt WHERE a.next_time > SYSDATE - 3 AND a.thread# = pt.VALUE AND ROUND(a.blocks * a.block_size / 1024 / 1024) > 0) GROUP BY next_time)) arc WHERE t.hour_end_time = (TRUNC(arc.next_time(+), 'HH') + (1 / 24))) WHERE hour_end_time > TRUNC(SYSDATE, 'HH') - 1 - (1 / 24)), v$instance i WHERE hour_end_time <= TRUNC(SYSDATE, 'HH') GROUP BY hour_end_time, i.instance_name ORDER BY hour_end_time /
Sample Output:
HOUR_END_TIME SIZE_MB INSTANCE_NAME ------------- ---------- ---------------- 2011/9/29 1:0 2.92 VPROD1 2011/9/29 2:0 2.92 VPROD1 2011/9/29 3:0 2.92 VPROD1 2011/9/29 4:0 2.92 VPROD1 2011/9/29 5:0 2.92 VPROD1 2011/9/29 6:0 2.92 VPROD1 2011/9/29 7:0 2.92 VPROD1 2011/9/29 8:0 2.92 VPROD1 2011/9/29 9:0 2.92 VPROD1 2011/9/29 10: 2.92 VPROD1 2011/9/29 11: 2.92 VPROD1 2011/9/29 12: 3.537 VPROD1 2011/9/29 13: 3.55 VPROD1 2011/9/29 14: 3.55 VPROD1 2011/9/29 15: 3.55 VPROD1 2011/9/29 16: 3.55 VPROD1 2011/9/29 17: 3.55 VPROD1 2011/9/29 18: 3.55 VPROD1 2011/9/29 19: 3.55 VPROD1 2011/9/29 20: 3.55 VPROD1
另一方法:可以通过awr中的每个快照的信息去收集redo size
SELECT to_date(end_time, ‘yyyy-mm-dd hh24:mi:ss’) as day
,trunc(redo_size/1024/60/60) “redo_size_KB/s”
— ,500000 baseline
FROM (SELECT to_char(c.end_interval_time, ‘yyyy-mm-dd hh24:mi:ss’) AS end_time
,decode(sign(a.value – b.value),-1,0,a.value – b.value) AS redo_size
FROM sys.wrh$_sysstat a
,sys.wrh$_sysstat b
,sys.wrm$_snapshot c
WHERE a.stat_id = 1236385760
AND b.stat_id = 1236385760
AND a.snap_id = b.snap_id + 1
AND a.instance_number = 1
AND b.instance_number = 1
AND c.instance_number=1
AND a.snap_id = c.snap_id
ORDER BY a.snap_id) x
good!
两种方法的估算误差太大了,还是先手工切换日志,然后用操作系统的文件大小来算比较接近实际情况的