Oracle GoldenGate 12c Implementer's Guide

Data selection and filtering

In addition to column mapping, GoldenGate offers two data filtering options:

• Complex: Complex data evaluations use the FILTER clause. FILTER can select rows and columns for a given operation, whereas WHERE just selects rows. FILTER can also use GoldenGate's built-in functions.
• Noncomplex: This filtering is achieved through the WHERE clause in a TABLE (Extract) or MAP (Replicat) statement.

As a rule of thumb, it is best practice to adopt the following strategy to avoid any performance overhead associated with data selection and filtering:

• Avoid data filtering on the primary Extract group, thus avoiding slow extract of LCRs from the database redo logs.
• Use a secondary Extract group (data pump) to filter data and potentially ...