5.1. Oracle Replication using Redo Reader

Replication Operation Support
Statements Replicated No
Rows Replicated Yes
Schema Replicated Yes, with limitations
ddlscan Supported Yes, supported for mixed Oracle/MySQL, and data warehouse targets

To extract information from an Oracle database two options are available, the CDC process (for more information, see Section 5.7, “Deploying Oracle Replication using CDC”), and a system that reads information directly from the Oracle redo log. This includes another process that runs alongside the Replicator and extracts events from the Oracle Redo Log. The functionality listed here is only available in the release named vmware-continuent-replication-oracle-source. Contact your sales representative if you don't have access to that build.

Replication with the Oracle Read Reader operates as follows:

  • A separate VMware Redo Reader process accesses and parses the content from the Oracle redo and supplemental logs, generating the individual transaction information into a format called the PLOG. The information in the PLOG contains each individual transaction, including limited DDL statements, in a format that can be processed by the Tungsten Replicator. This component is configured and installed automatically during the standard Tungsten Replicator deployment process.

  • The Tungsten Replicator reads the information from the PLOG and converts it into the Transaction History Log (THL) used by the replicator to store events and transactions. Once the transactions have been converted into the internal THL format, the information can be used by any downstream replicator to apply the data into another Oracle instance, or heterogeneous target such as MySQL or data warehouses.

Figure 5.1. Topologies: Oracle to Oracle with Redo Reader

Topologies: Oracle to Oracle with Redo Reader

Tungsten Replicator with Redo Log processing is supported within the following environments:

  • Oracle 9.2 (Experimental), 10g, 11g, 12c

  • Enterprise Edition (EE), Standard Edition (SE), Standard One (SE1) and Express Edition (XE)

  • Oracle RAC (Experimental)

In addition, the following requirements and limitations are in effect: