Oracle 修改Archive歸檔時間

archive_lag_target  單位是秒 預設是0(不啟動)
低於30分鐘可能影響資料庫效能
建議值落於 1800~7200之間
alter system set archive_lag_target=1800 scope=both;




oracle的說明 Oracle針對redo log的說明

Setting the ARCHIVE_LAG_TARGET Initialization Parameter

When you set the ARCHIVE_LAG_TARGET initialization parameter, you cause Oracle to examine an instance's current online redo log periodically. If the following conditions are met the instance will switch the log:

• The current log was created prior to n seconds ago, and the estimated archival time for the current log is m seconds (proportional to the number of redo blocks used in the current log), where n + mexceeds the value of the ARCHIVE_LAG_TARGET initialization parameter.
• The current log contains redo records.

In an Oracle Real Application Clusters environment, the instance also nudges other threads into switching and archiving logs if they are falling behind. This can be particularly useful when one instance in the cluster is more idle than the other instances (as when you are running a 2-node primary/secondary configuration of Oracle Real Application Clusters).

Initialization parameter ARCHIVE_LAG_TARGET specifies the target of how many seconds of redo the standby could lose in the event of a primary shutdown or crash if the Data Guard environment is not configured in a no-data-loss mode. It also provides an upper limit of how long (in the number of seconds) the current log of the primary database can span. Because the estimated archival time is also considered, this is not the exact log switch time.

The following initialization parameter setting sets the log switch interval to 30 minutes (a typical value).

ARCHIVE_LAG_TARGET = 1800

A value of 0 disables this time-based log switching functionality. This is the default setting.

You can set the ARCHIVE_LAG_TARGET initialization parameter even if there is no standby database. For example, the ARCHIVE_LAG_TARGET parameter can be set specifically to force logs to be switched and archived.

ARCHIVE_LAG_TARGET is a dynamic parameter and can be set with the ALTER SYSTEM SET statement.

Caution: The ARCHIVE_LAG_TARGET parameter must be set to the same value in all instances of an Oracle Real Application Clusters environment. Failing to do so results in unspecified behavior and is strongly discouraged.