With Oracle GoldenGate 12c (22.214.171.124.x), you can now quickly load empty target tables with data from your source database. You could always do this in previous releases of Oracle GoldenGate, but the process has now been simplified using REST APIs and some scripting know-how. In this post, I’m going to show you, high level, how you can use the REST APIs and a bit of scripting to do an initial load of a two table with a single command.
In previous releases of Oracle GoldenGate, a similar task could be done, but it required you to include the Oracle Database Export/Import data pumps or some other drawn out process. With this new process, you can effectively get around that and only need to use trail files to perform the initial load.
In this scenario, I have two table with a total of 14,000 records in them. This will be a small example of an initial load, but you should get the idea behind how this will work. This approach will also work for adding tables into an existing replication scheme.
The below architcture diagram illistrates how the architecture would look with an existing GoldenGate capture running and incorprating an File-Based Initial Load process to load a few tables.
This may look a bit confusing, but this is quite simple to understand. The red items are the GoldenGate extract, trails (local and remote), and the GoldenGate replicat. This is an existing replication stream. The GoldenGate extract is capturing from the source database, moving transactions to the local trail file (aa). Then the DistroService picks up/reads the local trail and ships the transactions across the GoldenGate Path to the ReceiverService. The Receiver Service then writes to the remote trail (ab) where the GoldenGate replicat processes the transactions into the target database. Pretty simple and this is doing a continuous replication of transactions.
Now, you want to just setup a few new tables, but do not want to take the day or two it would take to configure, export, import, apply and then catch up. Along the bottom, is the initial load path (green) using a File-Based approach to initially load tables. This process is what I’ve scripted out to using cURL and Shell scripts. Normally, you would spend time doing an export/import for the table(s) that you want to move to the target system after setting up the initial load extract.
Using Oracle GoldenGate Microservices architecture, this initial load process can be simplied and done very quickly. Below is a link to a script which I wrote to perform an File-Based Initial Load within Oracle GoldenGate Microservices.
FB_InitialLoad.sh <— Use at your own risk! This is only an example script of how this can be done.
What this script does, is creates the File-Based Initial Load process and populates the two tables I’ve identified in the target system.
As you run this script, everything I needed to build has been reduced down to functions that I can call when needed within the script. Granted this script if very simple but it orchatrates the whole initial load process for the tables I wanted. After the tables have been loaded, then they can be merged into the existing replication stream.