Oracle GoldenGate – Initial Load Methods, Prerequisites and Limitations

Initial Load: Advantages of Oracle GoldenGate Methods

  • Work across heterogeneous database types and platforms
  • Does not require application down time
  • Read directly from source tables without locking tables
  • Fetch data in arrays to speed up performance
  • Use parallel processing with Where or SQLPredicate clauses, or the @Range function
  • Distribute data over multiple network controllers
  • Include flexible load alternatives, such as native bulk-load utilities
  • Enable change delivery to handle collisions with initial load
  • Support Big Data Targets using GoldenGate for Big Data

Initial Load Methods – GoldenGate

File to Replicate (Trail: Canonical Format) – Replicat via SQL
File to Database Utility (Formatted Text File) – Database Utility
Direct Load (Replicat directly) – Replicat via SQL
Direct Bulk Load (Replicat directly) – Replicat via SQL*Loader API

CA Initial Load: Oracle GoldenGate Methods

Extract to File (to Replicat)
Extract to File to Database Utility (e.g. SQLLDR)
Direct Load (Extract to Replicat)
Bulk Load (Extract to Replicat using Oracle SQL Loader API)

Initial Load: Resource Limitations

  1. How close are your systems?
  2. How large are your tables?
  3. What are the outage time constraints?
  4. How much disk space do you have to store changes?

Prerequisites for Initial Load

  1. Verify that all open transactions that existed when the real-time Extract was started are completed.
  2. Disable DDL processing.
  3. Prepare target tables.
  4. Configure the Manager process.
  5. Create a Data Definition file (if the source and target databases have dissimilar definitions).
  6. Create change-synchronization groups (for capture/replication transactional changes during the initial load).
  7. Share parameters between process groups.

Initial Load Methods – non GoldenGate

RMAN Clone with Replicat using START..ATCSN (Best Practice)
Oracle Database Data Pump with Replicat using DBOPTIONS ENABLE_INSTANTIATION_FILTERING (12.2+) (Best Practice)
Oracle Database Data Pump with Replicat sing START…AFTERCSN(Best Practice)
exp | imp
TTS (Transportable Tablespace)
CTAS (Create Table As Select)
Oracle Data Integrator (ODI) Load Plan
12c: Unplug and Plug a PDB (Can be used to patch or upgrade a PDB)
12c: Full Transportable Export/Import (Variation of TTS)
12c: Clone a PDB
12c: Clone a PDB with SNAPSHOT COPY
12c: Plug a Non CDB into a CDB (Can be used to upgrade or consolidate)
12c: Clone a Non CDB into a CDB (12.1.0.2.0)
12c: EM 12c DBaaS Snap Clone using EMC, ZFS or NetApp storage with CoW (Copy-On-Write Technology)
12c: Multitenant Pluggable Database Snapshot Cloning using ACFS, ZFS, or NetApp storage with CoW
12c: SQL Develop (Export Cart) (Used with Database Cloud Service and Migration)

Note: Copy-on-write (COW), sometimes referred to as implicit sharing or shadowing, is a resource-management technique used in computer programming to efficiently implement a “duplicate” or “copy” operation on modifiable resources. If a resource is duplicated but not modified, it is not necessary to create a new resource; the resource can be shared between the copy and the original. Modifications must still create a copy, hence the technique: the copy operation is deferred until the first write. By sharing resources in this way, it is possible to significantly reduce the resource consumption of unmodified copies, while adding a small overhead to resource-modifying operations.

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Muhammad Rawish Siddiqui

Master in Computer Science (Database Engineering) and PGD in Management Information System.
45+ Online Certifications, which includes EDRP (EC-Council Disaster Recovery Professional), Data Management, Security+, DBaaS - Cloud Certified Expert, Oracle Cloud Autonomous Database Specialist, Oracle Database Cloud Certified Professional, Oracle Cloud Infrastructure, OCP 7.3, 10g, 11g, 11i, R12, OCE/OCS 11i System Administration, Solaris, Linux and Real Application Cluster 10g, 11g, Oracle Autonomous Database, Real Application Cluster, Oracle Data Guard and Performance Tuning etc. .

Foremost interested areas include, Data Management, Oracle Databases and EBS Health Checks, Real Application Cluster, Disaster Recovery, GoldenGate and Oracle Cloud.
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