Wednesday, September 12, 2012

Rate of Redo Log Switching

This was tested on Oracle 9. You can produce a simple report to show how often your redo logs are switching by querying V$LOGHIST like this:

SQL> l
  1  select sequence#,
  2  to_char(first_time,'dd:MON:yy hh24:mi:ss')
  3  date_and_time
  4  from v$loghist
  5  where first_time > '03-SEP-12'
  6* order by sequence#
SQL> /

SEQUENCE# DATE_AND_TIME
---------- ------------------
    101579 03:SEP:12 00:16:51
    101580 03:SEP:12 00:21:11
    101581 03:SEP:12 00:24:23
    101582 03:SEP:12 00:29:05
    101583 03:SEP:12 02:14:01
    101584 03:SEP:12 02:17:48
    101585 03:SEP:12 02:18:50
    101586 03:SEP:12 02:19:21
    101587 03:SEP:12 02:19:56
    101588 03:SEP:12 02:42:49
    101589 03:SEP:12 02:44:45
    101590 03:SEP:12 02:44:58
    101591 03:SEP:12 02:45:14
    101592 03:SEP:12 02:45:33
    101593 03:SEP:12 03:03:59
    101594 03:SEP:12 03:04:09
    101595 03:SEP:12 03:04:18
    101596 03:SEP:12 03:04:27
    101597 03:SEP:12 03:04:38
    101598 03:SEP:12 03:04:55
    101599 03:SEP:12 03:05:17
    101600 03:SEP:12 03:05:43
    101601 03:SEP:12 03:06:04
    101602 03:SEP:12 03:06:27
    101603 03:SEP:12 03:07:43
    101604 03:SEP:12 03:08:23
    101605 03:SEP:12 03:10:39
    101606 03:SEP:12 03:11:26
    101607 03:SEP:12 03:12:07
    101608 03:SEP:12 03:12:36
    101609 03:SEP:12 03:13:07
    101610 03:SEP:12 03:13:32
    101611 03:SEP:12 03:14:08
    101612 03:SEP:12 03:14:24
    101613 03:SEP:12 03:14:36
    101614 03:SEP:12 03:15:20
    101615 03:SEP:12 03:18:13
    101616 03:SEP:12 03:22:50
    101617 03:SEP:12 03:24:58
    101618 03:SEP:12 03:25:17
    101619 03:SEP:12 03:27:32
    101620 03:SEP:12 03:34:42
    101621 03:SEP:12 03:36:47
    101622 03:SEP:12 03:40:00
    101623 03:SEP:12 03:42:27
    101624 03:SEP:12 03:47:02
    101625 03:SEP:12 03:58:22
Etc

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