1. When to Use
The main benefit of Integrated Replicat is the parallel processing. Integrated Replicat can automatically check dependencies and auto tune parallelism based on the workload. The parallelism is controlled by two parameters in the replicat parameter file PARALLELISM and MAX_PARALLELISM .
- PARALLELISM is the minimum number of parallel apply processes. Default is 4.
- MAX_PARALLELISM is the maximum number of apply servers. Default is 50.
2. Comparing with other Delivery Options
Different from the Classic Replicat,
- integrated replicat is a two-step process. We know that Classic Replicat directly connects to the target database via OCI (Oracle Call Interface) and delivers the SQL transactions. However, Integrated Replicat process only reads the GoldenGate trail files, constructs logical change records (LCR), and then delivers the LCRs to the Inbound Server. The Inbound Server runs inside the Oracle database, which collects the LCRs, calculates the dependencies, group transactions, and then applies the transactions to the target database. The replicat process still performs data filtering, mapping and transformations but doesn't apply the DML and DDL operations.
Different from Coordinated Replicat,
- Integrated replicat keeps the transaction boundaries. However, the transactions are applied asynchronously, which means if there is no dependency, the transactions are applied in parallel with random orders to optimize the performance. (Coordinated replicat breaks the transaction boundaries for parallel processing.)
- Integrated replicat automatically check dependencies while coordinated replicat requires you to make sure there is no dependency across replication threads.
When using the integrated replication, you need to know the following features [4]:
- EAGER_SIZE: Sets a threshold for the size of a transaction (in number of LCRs) after which Oracle GoldenGate starts applying data before the commit record is received. The default for Oracle GoldenGate is 9500. This is also called the "eager apply: features.
- MAX_SGA_SIZE: Controls the amount of shared memory used by the inbound server.
- MAX_PARALLELISM: Limits the number of apply servers that can be used when the load is heavy
The following is an example parameter file of an integrated replicat:
Replicat rep01 UserIdAlias oggadm DBOPTIONS INTEGRATEDPARAMS(parallelism 2) DiscardFile ./dirrpt/rpdw.dsc, Purge Map oggsrc.*, target oggtrg.*;
add replicat rep01 integrated exttrail ./dirdat/pn
Please refer to Tuning the Performance of Integrated Replicat for the details.
- Oracle Tutorials: Configuring Integrated Extract and Integrated Replicat Using Oracle GoldenGate 12c on Linux
- Understand Integrated Replicat Performance using the GGSCI STATS Command, September 17, 2015
- Latest GoldenGate/Database (OGG/RDBMS) Patch recommendations (Doc ID 2193391.1)
- Oracle GoldenGate Documentation 12.1.2: Additional Parameter Options for Integrated Replicat.