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, whereasWHERE
just selects rows.FILTER
can also use GoldenGate's built-in functions. - Noncomplex: This filtering is achieved through the
WHERE
clause in aTABLE
(Extract) orMAP
(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 ...
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