Limitations and Requirements for Using ALO Mode

Observe the following limitations and requirements when using Extract in ALO mode.

• Log resets (RESETLOG) cannot be done on the source database after the standby database is created.

• ALO cannot be used on a standby database if the production system is Oracle RAC and the standby database is non-RAC. In addition to both systems being Oracle RAC, the number of nodes on each system must be identical.

• ALO on Oracle RAC requires a dedicated connection to the source server. If that connection is lost, Oracle GoldenGate processing will stop.

• It is a best practice to use separate archive log directories when using Oracle GoldenGate for Oracle RAC in ALO mode. This will avoid any possibility of the same file name showing up twice, which could result in Extract returning an "out of order scn" error.

• The LOGRETENTION parameter defaults to DISABLED when Extract is in ALO mode. You can override this with a specific LOGRETENTION setting, if needed.