Data Guard alter database add supplemental log data Oracle Database Tips by Donald BurlesonDecember 14, 2015

10g Data Guard Supplemental Logging

Oracle Database 10g introduces two new options for identification key logging at the database level. With database-level identification key logging, the DBA can enable database-wide before image logging for all updates. In addition to PRIMARY KEY and UNIQUE INDEX, the following two new identification keys can also be used:

•  ALL - This option specifies that when a row is updated, all the columns of that row, except for columns of type LOB, LONG, LONG RAW, and user-defined types, are placed in the redo log file.
   

• FOREIGN KEY - This option causes the Oracle database to place all columns of a row's foreign key in the redo log file, if any column belonging to the foreign key is modified.

When identification key logging is enabled at the database level, minimal supplemental logging is enabled implicitly.

Table supplemental logging specifies, at the table level, which columns are to be supplementally logged. Identification key logging or user-defined conditional and unconditional supplemental log groups can be used to log supplemental information.

Identification of key logging at the table level offers the same options as those provided at the database level: all, primary key, foreign key, and unique index. However, when identification key logging is specified at the table level, only the specified table is affected.

Starting with Oracle Database 10g, supplemental logging statements are cumulative. For example, if two consecutive alter database add supplemental log data commands are issued, each with a different identification key, both keys are supplementally logged.