Very often in these forums I get asked the question regarding data types which GoldenGate supports or Oracle software versions or questions like can it work with a database running in NOARCHIVELOG mode or does it support Partitioned and Index Organised tables and so forth.
I have included some snippets taken from the official documentation as well as some of my own experiences and hopefully it will help answer many of the those frequently asked questions.
What Oracle Versions are supported?
Oracle 9.2 and above, Oracle 10.1 and 10.2 and Oracle 11gR1 and 11gR2
How many Extract or Replicat processes can we start?
GoldenGate supports upto 300 Extract and Replicat processes per GoldenGate instance. But keep in mind that each process consumes around 50 MB of memory.
What Oracle Data Types are supported?
BLOB (SECUREFILE and BASICFILE are both supported.)
XML data types
User defined types
Oracle GoldenGate supports user defined types (UDT) when the source and target objects have the same structure. The schema names can be different.
Oracle GoldenGate does not support REF types.
Oracle GoldenGate supports SDO_GEOMETRY, SDO_TOPO_GEOMETRY, and SDO_GEORASTER for Oracle 10g and later.
Non-Supported Data Types
Oracle GoldenGate supports the following DML operations made to regular tables, index organized tables, clustered tables, and materialized views.
Oracle GoldenGate supports tables with virtual columns, but does not capture change.
Tables created as EXTERNAL are not supported.
Tables created with table compression or OLTP table compression are not supported.
Materialized views created WITH ROWID are not supported.
Support for Sequences
Oracle GoldenGate supports the replication of sequence values by means of the SEQUENCE parameter
The cache size and the increment interval of the source and target sequences must be identical.
DDL Replication Support
Oracle Goldengate supports DDL operations on the following database objects:
Oracle GoldenGate supports the synchronization of TRUNCATE statements as well as part of the DDL synchronization support.
DDL On Oracle Reserved Schemas is not supported.
Because of a known issue in Oracle 10g, the Oracle recycle bin must be turned off to support Oracle GoldenGate DDL replication.
Source and Target database charactersets
The character set of the target database must be a superset of the character set of the source database.
Can I run the source database in NOARCHIVELOG mode?
Oracle GoldenGate reads the online redo logs by default, but will read the archived logs if an online log is not available. If using in NOARCHIVELOG mode ensure that the redo log files are created with a larger size and more memebsrs are created to prevent then form being recycled before the Extract process has completed processing them.
GoldenGate using Data Guard Standby as a source
You can configure the Extract process to read exclusively from the archived logs. This is known as Archived Log Only (ALO) mode. In this mode, Extract only reads from archived logs that are stored in a specified location. ALO mode allows Oracle GoldenGate to use production log files that are shipped over to a standby database as a data source for Oracle GoldenGate. The online logs will not be used.
Oracle GoldenGate will connect to the secondary database to get metadata and other required data as needed. Supplemental logging at the table level and the database level must be enabled for the tables from the source database.
How do we handle Triggers and ON-DELETE cascade constraints on the target?
For Oracle 10.2.0.5 and later patches, and for Oracle 188.8.131.52 and later, you can use the Replicat parameter DBOPTIONS with the SUPPRESSTRIGGERS option to cause Replicat to disable the triggers during its session.
For Oracle 184.108.40.206 and later, you can use the Replicat parameter DBOPTIONS with the DEFERREFCONST option to delay checking and enforcement of integrity constraints until the Replicat transaction commits.