What can cause a rapid frequency of log switches?

Oracle 9.2.0.4 / AIX 5.1

I'm looking at an issue with redo log switches.
As far as I know, a log switch will only happen
A) if the log is full
B) if someone enters an "alter system switch logfile"
C) if archive_log_target is set

I've been asked why there would be a log switch in less than a minute
(the redo logs are all 400 MB in size). The only answer I could think of
is that there is a lot of activity in the database. Is there some
possibility I'm overlooking?

In this case I don't have access to the server, but here is a short
snippet from the alert log:
----
Sun May  9 01:25:58 2004
Beginning log switch checkpoint up to RBA [0x31231.2.10], SCN:
0x025d.246ab5bd
Thread 1 advanced to log sequence 201265
  Current log# 22 seq# 201265 mem# 0: /oracle/PD2/origlogB/log_g22m1.dbf
  Current log# 22 seq# 201265 mem# 1: /oracle/PD2/mirrlogB/log_g22m2.dbf
Sun May  9 01:25:58 2004
ARC1: Evaluating archive   log 21 thread 1 sequence 201264
ARC1: Beginning to archive log 21 thread 1 sequence 201264
Creating archive destination LOG_ARCHIVE_DEST_1:
'/oracle/PD2/saparch/PD2arch1_201264.dbf'
ARC1: Completed archiving  log 21 thread 1 sequence 201264
Sun May  9 01:26:00 2004
Completed checkpoint up to RBA [0x31230.2.10], SCN: 0x025d.246a6860
Beginning global checkpoint up to RBA [0x31231.10fa9.10], SCN:
0x025d.246ab65b
Completed checkpoint up to RBA [0x31231.10fa9.10], SCN: 0x025d.246ab65b
Completed checkpoint up to RBA [0x31231.2.10], SCN: 0x025d.246ab5bd
Sun May  9 01:26:34 2004
Beginning log switch checkpoint up to RBA [0x31232.2.10], SCN:
0x025d.246abab2
Thread 1 advanced to log sequence 201266
  Current log# 27 seq# 201266 mem# 0: /oracle/PD2/origlogA/log_g27m1.dbf
  Current log# 27 seq# 201266 mem# 1: /oracle/PD2/mirrlogA/log_g27m2.dbf
---

----------------------------------------------------------------
Please see the official ORACLE-L FAQ: http://www.orafaq.com
----------------------------------------------------------------
To unsubscribe send email to:  oracle-l-request@xxxxxxxxxxxxx
put 'unsubscribe' in the subject line.
--
Archives are at http://www.freelists.org/archives/oracle-l/
FAQ is at http://www.freelists.org/help/fom-serve/cache/1.html
-----------------------------------------------------------------

Other related posts: