Friday, April 9, 2010

How to force log switch on every XXXX minutes (ARCHIVE_LAG_TARGET)

For performance reason It is preferred that redo switches should not be less than 15 minutes .So we must resize our redo logs optimally (for deatil look Redo logs sizing advisory article


When we plan our redo logs for peak hours.while off peak-hours the redo switch does not occur for hours .This sitiuation has some risk


  1. In a case of catastrophic hardware failure, we may lose our current redo log having a enormous long redo data.There is no way to recover transactions that are sitting in the current redo log .

  2. Standby and Primary database may not be close synchronous If you useMAXIMUM AVAILABILITY

so It will be better to switch log for each specified interval.ARCHIVE_LAG_TARGET parameter simply forces a log switch at a specified interval, and that can be very useful.


In order to set 15 minutes (900 seconds )


ALTER SYSTEM SET ARCHIVE_LAG_TARGET = 900 SCOPE=BOTH;


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