Configuring a Replicat for Java Delivery

9.4.1.2.1 Configuring a Replicat for Java Delivery

The Oracle GoldenGate Replicat process can be configured to send transaction data to the Oracle GoldenGate for Java module. Replicat consumes a local trail (for example dirdat/aa) and sends the data to the Java Delivery module. The Java module is responsible for processing all the data and applying it to the desired target.

Following is an example of adding a Replicat process:

ADD REPLICAT javarep, EXTTRAIL ./dirdat/aa

The process names and trail names used in the preceding example can be replaced with any valid name. Process names must be 8 characters or less, trail names must to be two characters. In the Replicat parameter file (javarep.prm), specify the location of the user exit library.

The Replicat process has transaction grouping built into the application. Transaction grouping can significantly improve performance when streaming data to a target database. Transaction grouping can also significantly improve performance when streaming data to Big Data applications. The Replicat parameter to control transaction grouping is the GROUPTRANSOPS variable in the Replicat configuration file. The default value of this variable is 1000 which means the Replicat process will attempt to group 1000 operations into single target transaction. Performance testing has generally shown that the higher the GROUPTRANSOPS the better the performance when streaming data to Big Data applications. Setting the GROUPTRANSOPS variable to 1 means that the original transaction boundaries from the source trail file (source database) will be maintained.

Table 9-1 User Exit Replicat Parameters

Parameter	Explanation
REPLICAT javarep	All Replicat parameter files start with the Replicat name
SOURCEDEFS ./dirdef/tcust.def	(Optional) If the input trail files do not contain the metadata records, the Replicat process requires metadata describing the trail data. This can come from a database or a source definitions file. This metadata defines the column names and data types in the trail being read (`./dirdat/aa`).
TARGETDB LIBFILE libggjava.so SET properties= dirprm/javarep.properties	The `TARGETDB LIBFILE` `libggjava.so` parameter serves as a trigger to initialize the Java module. The `SET` clause to specify the Java properties file is optional. If specified, it should contain an absolute or relative path (relative to the Replicat executable) to the properties file for the Java module. The default value is `replicat_name`.`properties` in the `dirprm` directory.
MAP schema., TARGET .*;	The tables to pass to the Java module; tables not included will be skipped. If mapping from source to target tables is required, one can use the `MAP source_specification TARGET target_specification` as describe in "Mapping and Manipulating Data" in Administering Oracle GoldenGate.
GROUPTRANSOPS 1000	Group source transactions into a single larger target transaction for improved performance. `GROUPTRANSOPS` of 1000 is the default setting. `GROUPTRANSOPS` sets a minimum value rather than an absolute value, to avoid splitting apart source transactions. Replicat waits until it receives all operations from the last source transaction in the group before applying the target transaction. For example, if transaction 1 contains 200 operations, and transaction 2 contains 400 operations, and transaction 3 contains 500 operations, then Replicat transaction contains all 1,100 operations even though `GROUPTRANSOPS` is set to the default of 1,000. Conversely, Replicat might apply a transaction before reaching the value set by `GROUPTRANSOPS` if there is no more data in the trail to process.

Parent topic: Configuring Oracle GoldenGate for Java Delivery