I just set ARCHIVE_LAG_TARGET to 15 min and this has what I got in last few hours: DAY HOUR LOGSWITCH COUNT ---------- ---- ---------------------- 2013-02-19 16 17 2013-02-19 17 20 2013-02-19 18 22 On Tue, Feb 19, 2013 at 1:50 PM, Andrew Kerber <andrew.kerber@xxxxxxxxx>wrote: > Oracle has a setting, archive_lag_target, that will force a log switch if > one has not been done in the time frame specified by archive_lag_target. > So when the redo activity is uneven, I usually set that parameter and set > the redo logs to a very large size. > > On Tue, Feb 19, 2013 at 11:48 AM, Paul Houghton < > Paul.Houghton@xxxxxxxxxxxxxxx> wrote: > >> Hi >> >> According to a number of oracle support notes, e.g. 147468.1 performance >> will be impacted if log switches more often than about once every 15 >> minutes. That note specifically says that performance will be impacted by >> switching once every 3 minutes, which is around what you are doing. >> >> So yes, you should increase the size of the redo logs to 4.5 - 6 times >> their current size unless you are sure you can reduce the number of >> switches by reducing the workload. >> >> We have a cron job which switches the log file every 15 minutes to ensure >> the standby is up to date, though I am not sure if this is needed any more >> (11.2). >> >> You may be able to talk with the application people to get them to spread >> the load. Sometimes you get a trendy time to start a batch process (say >> 2am) and everyone starts their process at this time, though I can't see a >> pattern in the data you posted. Does the application keep some kind of log >> or audit of what it was doing which you could consult to find out what was >> being run, or use AWR reports if you have tuning pack, or even statspack >> and tune that area of the application or move it to a quieter time? >> >> Hope this helps >> >> PaulH >> >> >> -- >> //www.freelists.org/webpage/oracle-l >> >> >> > > > -- > Andrew W. Kerber > > 'If at first you dont succeed, dont take up skydiving.' -- //www.freelists.org/webpage/oracle-l