Working with the EXTRACT and REPLICAT utilities of Oracle GoldenGate - Amazon Relational Database Service
Running the Oracle GoldenGate EXTRACT utilityRunning the Oracle GoldenGate REPLICAT utility

Working with the EXTRACT and REPLICAT utilities of Oracle GoldenGate

The Oracle GoldenGate utilities EXTRACT and REPLICAT work together to keep the source and target databases in sync via incremental transaction replication using trail files. All changes that occur on the source database are automatically detected by EXTRACT, then formatted and transferred to trail files on the Oracle GoldenGate on-premises or Amazon EC2 instance hub. After initial load is completed, the data is read from these files and replicated to the target database by the REPLICAT utility.

Running the Oracle GoldenGate EXTRACT utility

The EXTRACT utility retrieves, converts, and outputs data from the source database to trail files. The basic process is as follows:

  1. EXTRACT queues transaction details to memory or to temporary disk storage.

  2. The source database commits the transaction.

  3. EXTRACT writes the transaction details to a trail file.

  4. The trail file routes these details to the Oracle GoldenGate on-premises or the Amazon EC2 instance hub and then to the target database.

The following steps start the EXTRACT utility, capture the data from EXAMPLE.TABLE in source database OGGSOURCE, and create the trail files.

To run the EXTRACT utility

  1. Configure the EXTRACT parameter file on the Oracle GoldenGate hub (on-premises or Amazon EC2 instance). The following listing shows an example EXTRACT parameter file named $GGHOME/dirprm/eabc.prm.

    EXTRACT EABC
 
USERID oggadm1@OGGSOURCE, PASSWORD "my-password"
EXTTRAIL /path/to/goldengate/dirdat/ab 
 
IGNOREREPLICATES
GETAPPLOPS
TRANLOGOPTIONS EXCLUDEUSER OGGADM1
	 
TABLE EXAMPLE.TABLE;

  2. On the Oracle GoldenGate hub, log in to the source database and launch the Oracle GoldenGate command line interface ggsci. The following example shows the format for logging in.

    dblogin oggadm1@OGGSOURCE

  3. Add transaction data to turn on supplemental logging for the database table.

    add trandata EXAMPLE.TABLE

  4. Using the ggsci command line, enable the EXTRACT utility using the following commands.

    add extract EABC tranlog, INTEGRATED tranlog, begin now
add exttrail /path/to/goldengate/dirdat/ab 
   extract EABC, 
   MEGABYTES 100

  5. Register the EXTRACT utility with the database so that the archive logs are not deleted. This task allows you to recover old, uncommitted transactions if necessary. To register the EXTRACT utility with the database, use the following command.

    register EXTRACT EABC, DATABASE

  6. Start the EXTRACT utility with the following command.

    start EABC

Running the Oracle GoldenGate REPLICAT utility

The REPLICAT utility "pushes" transaction information in the trail files to the target database.

The following steps enable and start the REPLICAT utility so that it can replicate the captured data to the table EXAMPLE.TABLE in target database OGGTARGET.

To run the REPLICATE utility

  1. Configure the REPLICAT parameter file on the Oracle GoldenGate hub (on-premises or EC2 instance). The following listing shows an example REPLICAT parameter file named $GGHOME/dirprm/rabc.prm.

    REPLICAT RABC
 
USERID oggadm1@OGGTARGET, password "my-password"
 
ASSUMETARGETDEFS
MAP EXAMPLE.TABLE, TARGET EXAMPLE.TABLE;
    Note

    Specify a password other than the prompt shown here as a security best practice.

  2. Log in to the target database and launch the Oracle GoldenGate command line interface (ggsci). The following example shows the format for logging in.

    dblogin userid oggadm1@OGGTARGET

  3. Using the ggsci command line, add a checkpoint table. The user indicated should be the Oracle GoldenGate user account, not the target table schema owner. The following example creates a checkpoint table named gg_checkpoint.

    add checkpointtable oggadm1.oggchkpt

  4. To enable the REPLICAT utility, use the following command.

    add replicat RABC EXTTRAIL /path/to/goldengate/dirdat/ab CHECKPOINTTABLE oggadm1.oggchkpt

  5. Start the REPLICAT utility by using the following command.

    start RABC