Book Image

Oracle Goldengate 12c Implementers Guide

Book Image

Oracle Goldengate 12c Implementers Guide

Overview of this book

Table of Contents (21 chapters)
Oracle GoldenGate 12c Implementer's Guide
Credits
About the Author
About the Reviewers
www.PacktPub.com
Preface
GGSCI Commands
GoldenGate Installed Components
Acronyms
Index

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 reduce data volume for transmission to the target system.

  • Use a data pump on an intermediate system to filter data, thus avoiding any performance overhead on the source and target systems.

  • Use a Replicat to optimize data filtering on the target....