This documentation is for an unreleased version of Apache Flink CDC. We recommend you use the latest stable version.

Demo: Oracle CDC to Elasticsearch #

Create docker-compose.yml file using following contents:

version: '2.1'
services:
  oracle:
    image: goodboy008/oracle-19.3.0-ee:non-cdb
    ports:
      - "1521:1521"
  elasticsearch:
    image: elastic/elasticsearch:7.6.0
    environment:
      - cluster.name=docker-cluster
      - bootstrap.memory_lock=true
      - "ES_JAVA_OPTS=-Xms512m -Xmx512m"
      - discovery.type=single-node
    ports:
      - "9200:9200"
      - "9300:9300"
    ulimits:
      memlock:
        soft: -1
        hard: -1
      nofile:
        soft: 65536
        hard: 65536
  kibana:
    image: elastic/kibana:7.6.0
    ports:
      - "5601:5601"
    volumes:
      - /var/run/docker.sock:/var/run/docker.sock

The Docker Compose environment consists of the following containers:

Oracle: Oracle 19c database.
Elasticsearch: store the join result of the orders and products table.
Kibana: mainly used to visualize the data in Elasticsearch

To start all containers, run the following command in the directory that contains the docker-compose.yml file.

docker-compose up -d

This command automatically starts all the containers defined in the Docker Compose configuration in a detached mode. Run docker ps to check whether these containers are running properly. You can also visit http://localhost:5601/ to see if Kibana is running normally.

Don’t forget to run the following command to stop all containers after you finished the tutorial:

docker-compose down

Download following JAR package to <FLINK_HOME>/lib

Download links are available only for stable releases, SNAPSHOT dependencies need to be built based on master or release-branches by yourself.

Preparing data in Oracle database

Introduce the tables in Oracle:

docker-compose exec oracle sqlplus debezium/dbz@localhost:1521/ORCLCDB

BEGIN
EXECUTE IMMEDIATE 'DROP TABLE DEBEZIUM.PRODUCTS';
EXCEPTION
   WHEN OTHERS THEN
      IF SQLCODE != -942 THEN
         RAISE;
END IF;
END;
/

CREATE TABLE DEBEZIUM.PRODUCTS (
  ID NUMBER(9, 0) NOT NULL,
  NAME VARCHAR(255) NOT NULL,
  DESCRIPTION VARCHAR(512),
  WEIGHT FLOAT,
  PRIMARY KEY(ID)
);

BEGIN
EXECUTE IMMEDIATE 'DROP TABLE DEBEZIUM.ORDERS';
EXCEPTION
   WHEN OTHERS THEN
      IF SQLCODE != -942 THEN
         RAISE;
END IF;
END;
/

CREATE TABLE DEBEZIUM.ORDERS (
  ID NUMBER(9, 0) NOT NULL,
  ORDER_DATE TIMESTAMP(3) NOT NULL,
  PURCHASER VARCHAR(255) NOT NULL,
  QUANTITY NUMBER(9, 0) NOT NULL,
  PRODUCT_ID NUMBER(9, 0) NOT NULL,
  PRIMARY KEY(ID)
);

ALTER TABLE DEBEZIUM.PRODUCTS ADD SUPPLEMENTAL LOG DATA (ALL) COLUMNS;
ALTER TABLE DEBEZIUM.ORDERS ADD SUPPLEMENTAL LOG DATA (ALL) COLUMNS;

INSERT INTO DEBEZIUM.PRODUCTS VALUES (101, 'scooter', 'Small 2-wheel scooter', 3.14);
INSERT INTO DEBEZIUM.PRODUCTS VALUES (102, 'car battery', '12V car battery', 8.1);
INSERT INTO DEBEZIUM.PRODUCTS VALUES (103, '12-pack drill bits', '12-pack of drill bits with sizes ranging from #40 to #3', 0.8);
INSERT INTO DEBEZIUM.PRODUCTS VALUES (104, 'hammer', '12oz carpenter''s hammer', 0.75);
INSERT INTO DEBEZIUM.PRODUCTS VALUES (105, 'hammer', '14oz carpenter''s hammer', 0.875);
INSERT INTO DEBEZIUM.PRODUCTS VALUES (106, 'hammer', '16oz carpenter''s hammer', 1.0);
INSERT INTO DEBEZIUM.PRODUCTS VALUES (107, 'rocks', 'box of assorted rocks', 5.3);
INSERT INTO DEBEZIUM.PRODUCTS VALUES (108, 'jacket', 'water resistent black wind breaker', 0.1);
INSERT INTO DEBEZIUM.PRODUCTS VALUES (109, 'spare tire', '24 inch spare tire', 22.2);

INSERT INTO DEBEZIUM.ORDERS VALUES (1001, TO_TIMESTAMP('2020-07-30 10:08:22.001000', 'YYYY-MM-DD HH24:MI:SS.FF'), 'Jark', 1, 101);
INSERT INTO DEBEZIUM.ORDERS VALUES (1002, TO_TIMESTAMP('2020-07-30 10:11:09.001000', 'YYYY-MM-DD HH24:MI:SS.FF'), 'Sally', 2, 102);
INSERT INTO DEBEZIUM.ORDERS VALUES (1003, TO_TIMESTAMP('2020-07-30 12:00:30.001000', 'YYYY-MM-DD HH24:MI:SS.FF'), 'Edward', 2, 103);
INSERT INTO DEBEZIUM.ORDERS VALUES (1004, TO_TIMESTAMP('2020-07-30 15:22:00.001000', 'YYYY-MM-DD HH24:MI:SS.FF'), 'Jark', 1, 104);

Launch a Flink cluster and start a Flink SQL CLI

Execute following SQL statements in the Flink SQL CLI:

-- Flink SQL
-- checkpoint every 3000 milliseconds                       
Flink SQL> SET execution.checkpointing.interval = 3s;

Flink SQL> CREATE TABLE products (
    ID INT,
    NAME STRING,
    DESCRIPTION STRING,
    PRIMARY KEY (ID) NOT ENFORCED
  ) WITH (
    'connector' = 'oracle-cdc',
    'hostname' = 'localhost',
    'port' = '1521',
    'username' = 'dbzuser',
    'password' = 'dbz',
    'database-name' = 'ORCLCDB',
    'schema-name' = 'DEBEZIUM',  
    'table-name' = 'products'
  );

Flink SQL> CREATE TABLE orders (
   ID INT,
   ORDER_DATE TIMESTAMP(3),
   PURCHASER STRING,
   QUANTITY INT,
   PRODUCT_ID INT,
   ORDER_STATUS BOOLEAN
 ) WITH (
   'connector' = 'oracle-cdc',
   'hostname' = 'localhost',
   'port' = '1521',
   'username' = 'dbzuser',
   'password' = 'dbz',
   'database-name' = 'ORCLCDB',
   'schema-name' = 'DEBEZIUM',  
   'table-name' = 'orders'
 );

Flink SQL> CREATE TABLE enriched_orders (
   ORDER_ID INT,
   ORDER_DATE TIMESTAMP(3),
   PURCHASER STRING,
   QUANTITY INT,
   PRODUCT_NAME STRING,
   PRODUCT_DESCRIPTION STRING,
   PRIMARY KEY (ORDER_ID) NOT ENFORCED
 ) WITH (
     'connector' = 'elasticsearch-7',
     'hosts' = 'http://localhost:9200',
     'index' = 'enriched_orders_1'
 );

Flink SQL> INSERT INTO enriched_orders
 SELECT o.ID,o.ORDER_DATE,o.PURCHASER,o.QUANTITY, p.NAME, p.DESCRIPTION
 FROM orders AS o
 LEFT JOIN products AS p ON o.PRODUCT_ID = p.ID;

Check result in Elasticsearch

Check the data has been written to Elasticsearch successfully, you can visit Kibana to see the data.

Make changes in Oracle and watch result in Elasticsearch

Enter Oracle’s container to make some changes in Oracle, then you can see the result in Elasticsearch will change after executing every SQL statement:

docker-compose exec oracle sqlplus debezium/dbz@localhost:1521/ORCLCDB

INSERT INTO DEBEZIUM.ORDERS VALUES (1005, TO_TIMESTAMP('2020-07-30 15:22:00.001000', 'YYYY-MM-DD HH24:MI:SS.FF'), 'Jark', 5, 105);

UPDATE DEBEZIUM.ORDERS SET QUANTITY = 10 WHERE ID = 1002;

DELETE FROM DEBEZIUM.ORDERS WHERE ID = 1004;