Replicate data from PostgreSQL to MySQL

Before you begin

To successfully complete this quicktart, you must have the following:

A PostgreSQL installation to serve as the source database (Installation instructions follow in Environment set up).
Open port 5432 in your VCN's security list to be able to access PostgreSQL on its default port.
An HeatWave Database to serve as the target database.

Environment set up: PostgreSQL

To set up the environment for this Quickstart:

Run the following commands to install PostgreSQL.
1. Install PostgreSQL server:
```
sudo yum install postgresql-server
```
2. Install postgresql-contrib module to avoid this SQL exception:
```
sudo yum install postgresql-contrib
```
3. Create a new PostgreSQL database cluster:
```
sudo postgresql-setup --initdb
```
4. Enable the postgresql.service:
```
sudo systemctl enable postgresql.service
```
5. Start the postgresql.service:
```
sudo systemctl start postgresql.service
```
By default, PostgreSQL only allows local connections. Allow remote connectivity to PostgreSQL.
1. In /var/lib/pgsql/data/postgresql.conf, prepare the database for replication.
2. Locate and uncomment listen_addresses = 'localhost' and change localhost to an asterisk (*):
```
listen_addresses = '*'
```
3. Set the following parameters as follows:
  - wal_level = logical
  - max_replication_slots = 1
  - max_wal_senders = 1
  - track_commit_timestamp = on
  Note:
  Configure /var/lib/pgsql/data/pg_hba.conf to ensure that client authentication is set to allow connections from an Oracle GoldenGate host. For example, add the following:
```
#Allow connections from remote hosts
host    all    all    0.0.0.0/0    md5
```
  See The pg_hba.conf File for more information.
4. Restart PostgreSQL server:
```
sudo systemctl restart postgresql.service
```

If using Oracle Cloud Compute to host PostgreSQL, open port 5432:

sudo firewall-cmd --permanent --add-port=5432/tcp
sudo firewall-cmd --reload
sudo firewall-cmd --list-all

Open port 5432 in your VCN's security list.
Connect to PostgreSQL.
```
> sudo su - postgres
> psql
```
Note:
Alternatively, you can enter sudo su - postgres psql if the above example doesn't work.
Set up PostgreSQL.
1. Download and run seedSRCOCIGGLL_PostgreSQL.sql to set up the database and load the sample data.
2. Run the following commands to set up the user (ensure you replace <password> with an actual password):
```
create user ggadmin with password '<password>';
alter user ggadmin with SUPERUSER;
GRANT ALL PRIVILEGES ON DATABASE ociggll TO ggadmin;
```

Environment set up: MySQL

Open Port 3306, through which OCI GoldenGate can connect.
1. In the Oracle Cloud console, locate the subnet that the HeatWave database uses.
2. In the security list of the subnet, create an Ingress rule for Port TCP/3306.

Create a ggadmin user using the following script. Remember to replace <ggadmin-password> with a valid password:

CREATE USER 'ggadmin' IDENTIFIED BY '<ggadmin-password>';
GRANT SELECT, REPLICATION SLAVE, REPLICATION CLIENT, CREATE,CREATE VIEW, EVENT, INSERT, UPDATE, DROP,EXECUTE, DELETE ON *.* TO 'ggadmin';

Create target tables using sample schema.

Ensure the tables and user have been succesfully created.

Task 1: Create the OCI GoldenGate Resources

This quickstart example requires deployments and connections for both the source and target.

Create a deployment for the source PostgreSQL database.
Create a MySQL deployment for the target HeatWave Database.
Create a PostgreSQL connection.
1. For Type, select PostgreSQL Server from the dropdown.
2. For Database name, enter ociggll.
3. For Host, enter the public IP of the Compute instance that PostgreSQL runs on.
4. For Port, enter 5432.
5. For Username, enter ggadmin.
6. For Password, enter your password.
7. For Security Protocol, select Plain from the dropdown.
Create a HeatWave connection.
(Optional) If your HeatWave Database doesn't have a public endpoint, then create a connection to GoldenGate, and then assign this connection to the source PostgreSQL deployment.
Assign the source connection to the source PostgreSQL deployment.
Assign the target connection to the target MySQL deployment.

Task 2: Enable supplemental logging

To enable supplemental logging:

Launch the PostgreSQL GoldenGate deployment console:
1. From the Deployments page, select the PostgreSQL deployment to view its details.
2. On the PostgreSQL deployment details page, click Launch console.
3. On the deployment console sign in page, enter the GoldenGate admin credentials provided in Task 1, step 1.
In GoldenGate 23ai, click DB Connections in the left navigation, then the source PostgreSQL database, and then Trandata.
On the Trandata page, next to TRANDATA Information, click Add Trandata (plus icon).
In the Trandata panel, for Schema Name, enter src_ociggll.*, and then click Submit.

Note:
Use the search field to search for src_ociggll and verify the tables were added.

Task 3: Create the Extracts

Add the Change Data Capture Extract:
1. In the left navigation, click Extracts,
2. On the Extracts page, click Add Extract (plus icon), and then complete the fields as follows:
  - On the Extract Information page:
    1. For Extract type, select Change Data Capture Extract.
    2. For Process Name, enter a name for the Extract, such as ECDC.
    3. Click Next.
  - On the Extract Options page:
    1. For Source credentials, select Oracle GoldenGate from the Domain dropdown
    2. Select the source PostgreSQL database from the Alias dropdown.
    3. For Extract Trail Name, enter a two-character trail name, such as C1.
    4. Click Next.
  - On the Extract Parameters page, replace MAP *.*, TARGET *.*; with the following:
```
TABLE SRC_OCIGGLL.*;
```
3. Click Create and Run.
Add the Initial Load Extract:
1. On the Extracts page, click Add Extract, and then complete the Add Extract form as follows:
  - On the Extract Information page:
    1. For Extract type, select Initial Load Extract.
    2. For Process Name, enter a name, such as EIL.
    3. Click Next.
  - On the Extract Options page:
    1. For Source credentials, select Oracle GoldenGate from the Domain dropdown.
    2. Select the PostgreSQL database from the Alias, dropdown.
    3. For Extract Trail Name, enter a two-character trail name, such as I1.
    4. Click Next.
  - On the Extract Parameters page, replace the contents of the text area with the following:
```
EXTRACT EIL
USERIDALIAS PostgreSQL_Compute, DOMAIN OracleGoldenGate
EXTFILE I1, PURGE
TABLE src_ociggll.*;
```
    Note:
    Ensure that you remove the SOURCEDB parameter in front of USERIDALIAS before you move on.
2. Click Create and Run.

You return to the Extracts page, where you can observe the Extract starting.

Task 4: Create the Distribution Path for Initial Load Extract

To create a Distribution Path for Initial Load Extract, complete the following:

In the Oracle Cloud console, on the Deployments page, select the target MySQL deployment.
On the deployment details page, click Launch Console, and log in using the admin detailed created in task 1, step 2.
If using IAM credential store, proceed to the Create a Distribution Path step. If using GoldenGate credential store, create a user with which the source GoldenGate uses to connect to the target GoldenGate.
1. In the navigation menu, click User Administration.
2. Click Add New User (plus icon), complete the fields as follows, and then click Submit:
  - For Username, enter ggsnet.
  - For Role, select Operator.
  - Enter the password twice for verification.
In the source PostgreSQL deployment console, create a Path Connection for the user created in the previous step.
1. In the navigaton menu, click Path Connections.
2. Click Add Path Connection (plus icon), complete the fields as follows, and then click Submit:
  - For Credential Alias, enter dpuser.
  - For User ID, enter ggsnet
  - For Password, enter the same password used in the previous step.
Create a Distribution Path.
1. In the service menu bar, click Distribution Service, and then click Add Distribution Path (plus icon).
2. Complete the Add Path form as follows:
  - On the Path Information page:
    1. For Path Name, enter a name for this path.
    2. Click Next.
  - On the Source Options page:
    1. For Source Extract, leave blank.
    2. For Trail Name, enter the Initial Load Extract trail name (I1).
    3. Click Next.
  - On the Target Options page:
    1. For Target, select wss.
    2. For Target Host, enter the target deployment URL, without the https:// or any trailing slashes.
    3. For Port Number, enter 443.
    4. For Trail Name, enter I1.
    5. For Target Authentication Method, select UserID Alias.
    6. For Domain, enter the domain name created in the previous step.
    7. For Alias, enter the alias created in the previous step (dpuser).
    8. Click Next.
3. Click Create and Run.
You return to the Distribution Service page where you can review the path created.
In the target MySQL deployment console, review the Receiver path created as a result of the Distribution Path:
1. Click Receiver Service.
2. Review the Distribution Path details.

Task 5: Add the Replicat for Initial Load

In the target MySQL deployment console, add a Checkpoint table.
1. In the navigation menu, select DB Connections, the target HeatWave Database, and then Checkpoints.
2. Click Add Checkpoint (plus icon).
3. In the Checkpoint pane, For Schema Table, enter SRCMIRROR_OCIGGLL.CHECKTABLE.
4. Click Submit.
Add the Initial Load Replicat.
1. In the navigation menu, click Replicats, and then click Add Replicat (plus icon).
2. On the Replicats page, then complete the Add Replicat fields as follows:
  1. On the Replicat Information page:
    1. For Replicat type, select Parallel or Coordinated.
    2. For Process Name, enter a name, such as RIL.
    3. Click Next.
  2. On the Replicat Options page:
    1. For Replicat Trail Name, enter the name of the Trail from Task 2 (I1).
    2. For Target Credentials, select the Domain and Alias for the HeatWave Database connection.
    3. For Checkpoint Table, select the Checkpoint table you created in Step 1.
    4. Click Next.
  3. On the Parameter File page, add the following mapping:
```
MAP src_ociggll.*, TARGET SRCMIRROR_OCIGGLL.*;
```
3. Click Create and Run.
You return to the Replicats page, where you can review the Replicat details.
Verify the Initial Load:
1. In Cloud Shell, connect to the VCN and subnet used by your HeatWave instance.
2. Once connected, run the following command :
```
mysqlsh <user>@<MySQL DB Private IP>:3306 --sql
```
3. Run the following script to verify the data:
```
select * from SRCMIRROR_OCIGGLL.SRC_CITY;
select * from SRCMIRROR_OCIGGLL.SRC_CUSTOMER;
```
  The output should return the data that was loaded into the target database tables as a result of the Initial Load.

Task 6: Create the Distribution Path for Change Data Capture

To create a Distribution Path for Change Data Capture, complete the following:

In the source PostgreSQL deployment console, click Distribution Service.
Click Add Distribution Path.
Complete the Add Path form as follows:
1. On the Path Information page:
  1. For Path Name, enter a name.
  2. Click Next.
2. On the Source Options page:
  1. For Source Extract, select the Change Data Capture Extract (ECDC).
  2. For Trail Name, select the Change Data Capture trail file (C1).
  3. Click Next.
3. On the Target Options page:
  1. For Target, select wss.
  2. For Target Host, enter the target deployment console URL (you can find this on the deployment details page, without the https:// or any trailing slashes.
  3. For Port Number, enter 443.
  4. For Trail Name, enter C1.
  5. For Target Authentication Method, select UserID Alias.
  6. For Domain, enter the domain name.
  7. For Alias, enter the alias.
4. Click Create Path and Run.
In the target MySQL deployment console, click Receiver Service, and then review the Receiver Path created.

Task 7: Add a Replicat for Change Data Capture

Perform updates to the source PostgreSQL database to verify replication to target HeatWave Database.

Add Replicat:
1. In the target deployment console, click Administration Service, and then in the navigation menu, click Replicats.
2. On the Replicats page, click Add Replicat (plus icon), and then complete the Add Replicat form as follows:
  - On the Replicat Information page:
    1. For Replicat type, select Nonintegrated Replicat.
    2. For Process Name, enter a name, such as RCDC.
    3. Click Next.
  - On the Replicat Options page:
    1. For Replicat Trail Name, enter the name of the Trail from Task 3 (C1).
    2. For Target Credentials, select the Domain and Alias for the HeatWave connection.
    3. For Checkpoint Table, select the Checkpoint table.
3. On the Replicat Parameters page, replace MAP *.*, TARGET *.*; with the following mapping:
```
MAP src_ociggll.*, TARGET SRCMIRROR_OCIGGLL.*;
```
4. Click Create and Run.
  
  You return to the Replicats page, where you can review the Replicat details.

Verify Change Data Capture:

Perform updates to the source PostgreSQL database to verify replication to the target HeatWave Database. Run the following script to perform inserts into the PostgreSQL database:

Insert into src_ociggll.src_city (CITY_ID,CITY,REGION_ID,POPULATION) values (1000,'Houston',20,743113);
Insert into src_ociggll.src_city (CITY_ID,CITY,REGION_ID,POPULATION) values (1001,'Dallas',20,822416);
Insert into src_ociggll.src_city (CITY_ID,CITY,REGION_ID,POPULATION) values (1002,'San Francisco',21,157574);
Insert into src_ociggll.src_city (CITY_ID,CITY,REGION_ID,POPULATION) values (1003,'Los Angeles',21,743878);
Insert into src_ociggll.src_city (CITY_ID,CITY,REGION_ID,POPULATION) values (1004,'San Diego',21,840689);
Insert into src_ociggll.src_city (CITY_ID,CITY,REGION_ID,POPULATION) values (1005,'Chicago',23,616472);
Insert into src_ociggll.src_city (CITY_ID,CITY,REGION_ID,POPULATION) values (1006,'Memphis',23,580075);
Insert into src_ociggll.src_city (CITY_ID,CITY,REGION_ID,POPULATION) values (1007,'New York City',22,124434);
Insert into src_ociggll.src_city (CITY_ID,CITY,REGION_ID,POPULATION) values (1008,'Boston',22,275581);
Insert into src_ociggll.src_city (CITY_ID,CITY,REGION_ID,POPULATION) values (1009,'Washington D.C.',22,688002);

In the source PostgreSQL deployment console, select the Change Data Capture Extract name (ECDC), click Details, and then click Statistics. Verify that src_ociggll.src_city has 10 inserts.

Note:
If the Extract captured no inserts, then restart the ECDC Extract.
In the target MySQL deployment, select the RCDC Replicat, review its Details and Statistics to verify the number of Inserts.