OGG has 2 functionalities, one it is used for Online data Replication and second for Initial Loading.

If you are replicating data between 2 homogeneous databases then the best method is to use database specific method (Exp/Imp, RMAN, Transportable tablespaces, Physical Standby and so on). Database specific methods are usually faster than the other methods.

—If you are replicating data between 2 heterogeneous databases or your replicat involves complex transformations, then the database specific method can’t be used. In those cases you can ALWAYS use Oracle GoldenGate to perform initial load.

Within Oracle GoldenGate you have 4 different ways to perform initial load.

• Direct Load – Faster but doesn’t SUPPORT LOB data types (12c include support for LOB)
• Direct Bulk Load – Uses SQL*LOAD API for Oracle and SSIS for MS SQL SERVER
• File to replicat – Fast but the rmtfile limit is 2GB. If the table can’t be fit in 1 rmtfile you can use maxfiles but the replicat NEED to be registered on the target OGG home to read the rmtfiles from source.
• File to Database utility – depending on the target database, use SQL*LOAD for Oracle and SSIS for MS SQL SERVER and so on.

Oracle GoldenGate initial loading reads data directly from the source database tables without locking them. So you don’t need downtime but it will use database resources and can cause performance issues. Take extra precaution to perform the initial load during the non-peak time so that you don’t run into resource contention.

OGG has 2 functionalities, one it is used for Online data Replication and second for Initial Loading.

If you are replicating data between 2 homogeneous databases then the best method is to use database specific method (Exp/Imp, RMAN, Transportable tablespaces, Physical Standby and so on). Database specific methods are usually faster than the other methods.

—If you are replicating data between 2 heterogeneous databases or your replicat involves complex transformations, then the database specific method can’t be used. In those cases you can always use Oracle GoldenGate to perform initial load.

Within Oracle GoldenGate you have 4 different ways to perform initial load.

Oracle GoldenGate initial loading reads data directly from the source database tables without locking them. So you don’t need downtime but it will use database resources and can cause performance issues. Take extra precaution to perform the initial load during the non-peak time so that you don’t run into resource contention.