You can use multiple process groups to support certain kinds of tables that tend to interfere with normal processing and cause latency to build on the target. For example:

• Extract may need to perform a fetch from the database because of the data type of the column, because of parameter specifications, or to perform SQL procedures. When data must be fetched from the database, it affects the performance of Extract. You can get fetch statistics from the STATS EXTRACT command if you include the STATOPTIONS REPORTFETCH parameter in the Extract parameter file. You can then isolate those tables into their own Extract groups, assuming that transactional integrity can be maintained.

• In its classic mode, Replicat process can be a source of performance bottlenecks because it is a single-threaded process that applies operations one at a time by using regular SQL. Even with BATCHSQL enabled (see Reference for Oracle GoldenGate) Replicat may take longer to process tables that have large or long-running transactions, heavy volume, a very large number of columns that change, and LOB data. You can then isolate those tables into their own Replicat groups, assuming that transactional integrity can be maintained.