clickhouse-sink-connector/sink-connector-lightweight

Altinity Replicator for ClickHosue

Getting started (MySQL)

Currently the configuration is passed to the application as environment variables.
(sink-connector-lightweight/docker/docker.env)

Configuration

export database.hostname="mysql-master"
export database.port="3306"
export database.user="root"
export database.password="root"
export database.include.list=sbtest
export clickhouse.server.url="clickhouse"
export clickhouse.server.user="root"
export clickhouse.server.pass="root"
export clickhouse.server.port="8123"
#export table.include.list=sbtest1
export database.allowPublicKeyRetrieval"="true"
export snapshot.mode="schema_only"
export connector.class="io.debezium.connector.mysql.MySqlConnector"
export clickhouse.server.database="test"
export auto.create.tables=true
export replacingmergetree.delete.column="_sign"
export metrics.port=8083

After the environment variables are set, start the docker container A Sample docker-compose is provided , it starts the docker container
registry.gitlab.com/altinity-public/container-images/clickhouse_debezium_embedded:latest

cd sink-connector-lightweight
cd docker
docker-compose up

Getting Started (PostgreSQL)

(sink-connector-lightweight/docker/docker_postgres.env)

Configuration

export database.hostname="postgres"
export database.port="5432"
export database.user="root"
export database.password="root"
export snapshot.mode="schema_only"
export clickhouse.server.url="clickhouse"
export clickhouse.server.user="root"
export clickhouse.server.pass="root"
export clickhouse.server.port="8123"
export connector.class="io.debezium.connector.postgresql.PostgresConnector"
export plugin.name="pgoutput"
export table.include.list="public.tm"
export clickhouse.server.database="test"
export auto.create.tables=true
export replacingmergetree.delete.column="_sign"
export metrics.port=8083

After the environment variables are set, start the docker container

cd sink-connector-lightweight
cd docker
docker-compose up -f docker-compose-postgres.yml

Getting Started (MongoDB)

(sink-connector-lightweight/docker/docker_mongo.env)

Configuration

export mongodb.connection.string="mongodb://localhost:49252"
export mongodb.members.auto.discover="true"
export topic.prefix="mongo-ch"
export collection.include.list="project.items"
export snapshot.include.collection.list="project.items"
export database.include.list="project"
export database.dbname="project"
export database.user="project"
export database.password="project"
export snapshot.mode="initial"
export connector.class="io.debezium.connector.mongodb.MongoDbConnector"
export offset.storage="org.apache.kafka.connect.storage.FileOffsetBackingStore"
export offset.flush.interval.ms="60000"
export auto.create.tables="true"
export clickhouse.server.url="clickhouse"
export clickhouse.server.port="8123"
export clickhouse.server.user="root"
export clickhouse.server.pass="root"
export clickhouse.server.database="project"
export replacingmergetree.delete.column="_sign"
export metrics.port="8087"
export database.allowPublicKeyRetrieval="true"

After the environment variables are set, start the docker container

cd sink-connector-lightweight
cd docker
docker-compose up -f docker-compose-mongo.yml

Getting Started (Helm Charts)

Helm Charts

Update the MySQL/PostgreSQL and ClickHouse configuration values `

  - name: database.hostname
    value: "127.0.0.1"
  - name: database.port
    value: "3306"
  - name: database.dbname
    value: "public"
  - name: database.user
    value: "root"
  - name: database.password
    value: "adminpass"
  - name: snapshot.mode
    value: "initial"
  - name: connector.class
    value: "io.debezium.connector.postgresql.PostgresConnector"
  - name: plugin.name
    value: "pgoutput"
  - name: table.include.list
    value: "public.tm"
  - name: offset.storage
    value: "org.apache.kafka.connect.storage.FileOffsetBackingStore"
  - name: offset.storage.file.filename
    value: "filename"
  - name: offset.flush.interval.ms
    value: "60000"
  - name: auto.create.tables
    value: "true"
  - name: clickhouse.server.url
    value: "localhost"
  - name: clickhouse.server.port
    value: "8123"
  - name: clickhouse.server.user
    value: "default"
  - name: clickhouse.server.pass
    value: "2"
  - name: clickhouse.server.database
    value: "public"
  - name: replacingmergetree.delete.column
    value: "_sign"
  - name: database.allowPublicKeyRetrieval
    value: "true"
  - name: metrics.enable
    value: "true"
  - name: metrics.port
    value: "8083"

cd helm
helm install clickhouse-debezium-embedded .

Building from sources

Build the JAR file mvn clean install

DDL Support:

With Datatype conversion(From MySQL to ClickHouse)

ALTER TABLE

MySQL	ClickHouse
ADD COLUMN
ADD COLUMN NULL/NOT NULL
ADD COLUMN DEFAULT
ADD COLUMN FIRST, AFTER
DROP COLUMN
MODIFY COLUMN data_type
MODIFY COLUMN data_type NULL/NOT NULL
MODIFY COLUMN data_type DEFAULT
MODIFY COLUMN FIRST, AFTER
MODIFY COLUMN old_name new_name datatype NULL/NOT NULL
RENAME COLUMN col1 to col2
CHANGE COLUMN FIRST, AFTER	MODIFY COLUMN
ALTER COLUMN col_name ADD DEFAULT	Not supported by grammar
ALTER COLUMN col_name ADD DROP DEFAULT	Not supported by grammar
ADD PRIMARY KEY	Cannot modify primary key in CH

TABLE operations

MySQL	ClickHouse
RENAME TABLE name_1 to name_2
TRUNCATE TABLE
DROP TABLE name_1
DROP TABLE name_1, name_2
ALTER TABLE table_name to new_table_name	RENAME table_name to new_table_name
CREATE TABLE PARTITION BY KEY(col1)	PARTITION BY col1
CREATE TABLE PARTITION BY RANGE(col1,col2, col3)	PARTITION BY col1, col2, col3

DATABASE operations

MySQL	ClickHouse
CREATE DATABASE
USE DATABASE

Not supported:

MySQL	ClickHouse
ADD INDEX	Secondary indexes in CH, what about type and index granularity?
ADD CONSTRAINT (CHECK)
ADD CONSTRAINT	Add constraint with Primary key(Not supported)
DROP CONSTRAINT	Add constraint with Primary key(Not supported)