Nor more Checkpoints at every log-switch in 10.2 ?

Question

Hi,
i working with Oracle about 12 years but i havn´t seen this before:
REM There is no work/application in the database now:
select group#,status from v$log;
GROUP# STATUS
1 CURRENT
2 ACTIVE
4 ACTIVE
5 ACTIVE
6 ACTIVE
First as i know only one or two (for a short time) shiould be active.
OK wait 90 seconds:
SQL> /
GROUP# STATUS
1 CURRENT
2 ACTIVE
4 ACTIVE
5 ACTIVE
6 ACTIVE
Try a log switch:
alter system switch logfile;
SQL> select group#,status from v$log;
GROUP# STATUS
1 ACTIVE
2 CURRENT
4 ACTIVE
5 ACTIVE
6 ACTIVE
How can i now drop one of the redo-logs ?
=> Solution:
alter system checkpoint;
select group#,status from v$log;
GROUP# STATUS
1 INACTIVE
2 CURRENT
4 INACTIVE
5 INACTIVE
6 INACTIVE
Does anybody know what Oracle changed here ?
Thanks in advance
Marco

Answer 1

hi,
welcome to Oracle10g:
show paramater FAST_START_MTTR_TARGET
if it is '0', then auto-checking-pointing is DISABLED, this happens to be the default on Oracle XE (under review)
By default, Oracle 10g supports automatic checkpoint tuning by making the best effort to write out SGA buffer cache dirty buffers w/o impacting the throughput of runtime physical I/O, thus achieving reasonable crash recovery time.
Setting the FAST_START_MTTR_TARGET parameter to a non-zero value or not setting this parameter enables automatic checkpoint tuning. The STATISTICS_LEVEL must be TYPICAL OR ALL. After a period of time, see V$MTTR_TARGET_ADVICE for various value for this parameter.