Schema evolution

Schema Evolution means that the schema of a data table can be changed and the data synchronization task can automatically adapt to the changes of the new table structure without any other operations.

Supported engines

• Zeta

Supported schema change event types

• ADD COLUMN
• DROP COLUMN
• RENAME COLUMN
• MODIFY COLUMN

Supported connectors

Source

Mysql-CDC Oracle-CDC

Sink

Jdbc-Mysql Jdbc-Oracle Jdbc-Postgres StarRocks Doris Paimon Elasticsearch

Note: The schema evolution is not support the transform at now. The schema evolution of different types of databases（Oracle-CDC -> Jdbc-Mysql）is currently not supported the default value of the column in ddl.

When you use the Oracle-CDC，you can not use the username named SYS or SYSTEM to modify the table schema, otherwise the ddl event will be filtered out which can lead to the schema evolution not working. Otherwise, If your table name start with ORA_TEMP_ will also has the same problem.

Enable schema evolution

Schema evolution is disabled by default in CDC source. You need configure schema-changes.enabled = true which is only supported in CDC to enable it.

Examples

Mysql-CDC -> Jdbc-Mysql

env {
  # You can set engine configuration here
  parallelism = 5
  job.mode = "STREAMING"
  checkpoint.interval = 5000
  read_limit.bytes_per_second=7000000
  read_limit.rows_per_second=400
}

source {
  MySQL-CDC {
    server-id = 5652-5657
    username = "st_user_source"
    password = "mysqlpw"
    table-names = ["shop.products"]
    base-url = "jdbc:mysql://mysql_cdc_e2e:3306/shop"
    
    schema-changes.enabled = true
  }
}

sink {
  jdbc {
    url = "jdbc:mysql://mysql_cdc_e2e:3306/shop"
    driver = "com.mysql.cj.jdbc.Driver"
    user = "st_user_sink"
    password = "mysqlpw"
    generate_sink_sql = true
    database = shop
    table = mysql_cdc_e2e_sink_table_with_schema_change_exactly_once
    primary_keys = ["id"]
    is_exactly_once = true
    xa_data_source_class_name = "com.mysql.cj.jdbc.MysqlXADataSource"
  }
}

Oracle-cdc -> Jdbc-Oracle

env {
  # You can set engine configuration here
  parallelism = 1
  job.mode = "STREAMING"
  checkpoint.interval = 5000
}

source {
  # This is a example source plugin **only for test and demonstrate the feature source plugin**
  Oracle-CDC {
    plugin_output = "customers"
    username = "dbzuser"
    password = "dbz"
    database-names = ["ORCLCDB"]
    schema-names = ["DEBEZIUM"]
    table-names = ["ORCLCDB.DEBEZIUM.FULL_TYPES"]
    base-url = "jdbc:oracle:thin:@oracle-host:1521/ORCLCDB"
    source.reader.close.timeout = 120000
    connection.pool.size = 1
    
    schema-changes.enabled = true
  }
}

sink {
    Jdbc {
      plugin_input = "customers"
      driver = "oracle.jdbc.driver.OracleDriver"
      url = "jdbc:oracle:thin:@oracle-host:1521/ORCLCDB"
      user = "dbzuser"
      password = "dbz"
      generate_sink_sql = true
      database = "ORCLCDB"
      table = "DEBEZIUM.FULL_TYPES_SINK"
      batch_size = 1
      primary_keys = ["ID"]
      connection.pool.size = 1
    }
}

Oracle-cdc -> Jdbc-Mysql

env {
  # You can set engine configuration here
  parallelism = 1
  job.mode = "STREAMING"
  checkpoint.interval = 5000
}

source {
  # This is a example source plugin **only for test and demonstrate the feature source plugin**
  Oracle-CDC {
    plugin_output = "customers"
    username = "dbzuser"
    password = "dbz"
    database-names = ["ORCLCDB"]
    schema-names = ["DEBEZIUM"]
    table-names = ["ORCLCDB.DEBEZIUM.FULL_TYPES"]
    base-url = "jdbc:oracle:thin:@oracle-host:1521/ORCLCDB"
    source.reader.close.timeout = 120000
    connection.pool.size = 1
    
    schema-changes.enabled = true
  }
}

sink {
  jdbc {
    plugin_input = "customers"
    url = "jdbc:mysql://oracle-host:3306/oracle_sink"
    driver = "com.mysql.cj.jdbc.Driver"
    user = "st_user_sink"
    password = "mysqlpw"
    generate_sink_sql = true
    # You need to configure both database and table
    database = oracle_sink
    table = oracle_cdc_2_mysql_sink_table
    primary_keys = ["ID"]
  }
}

Mysql-cdc -> StarRocks

env {
  # You can set engine configuration here
  parallelism = 1
  job.mode = "STREAMING"
  checkpoint.interval = 5000
}

source {
  MySQL-CDC {
    username = "st_user_source"
    password = "mysqlpw"
    table-names = ["shop.products"]
    base-url = "jdbc:mysql://mysql_cdc_e2e:3306/shop"
    
    schema-changes.enabled = true
  }
}

sink {
  StarRocks {
    nodeUrls = ["starrocks_cdc_e2e:8030"]
    username = "root"
    password = ""
    database = "shop"
    table = "${table_name}"
    base-url = "jdbc:mysql://starrocks_cdc_e2e:9030/shop"
    max_retries = 3
    enable_upsert_delete = true
    schema_save_mode="RECREATE_SCHEMA"
    data_save_mode="DROP_DATA"
    save_mode_create_template = """
    CREATE TABLE IF NOT EXISTS shop.`${table_name}` (
        ${rowtype_primary_key},
        ${rowtype_fields}
        ) ENGINE=OLAP
        PRIMARY KEY (${rowtype_primary_key})
        DISTRIBUTED BY HASH (${rowtype_primary_key})
        PROPERTIES (
                "replication_num" = "1",
                "in_memory" = "false",
                "enable_persistent_index" = "true",
                "replicated_storage" = "true",
                "compression" = "LZ4"
          )
    """
  }
}

Mysql-CDC -> Doris

env {
  # You can set engine configuration here
  parallelism = 1
  job.mode = "STREAMING"
  checkpoint.interval = 5000
}

source {
  MySQL-CDC {
    server-id = 5652-5657
    username = "st_user_source"
    password = "mysqlpw"
    table-names = ["shop.products"]
    base-url = "jdbc:mysql://mysql_cdc_e2e:3306/shop"
    schema-changes.enabled = true
  }
}

sink {
  Doris {
    fenodes = "doris_e2e:8030"
    username = "root"
    password = ""
    database = "shop"
    table = "products"
    sink.label-prefix = "test-cdc"
    sink.enable-2pc = "true"
    sink.enable-delete = "true"
    doris.config {
      format = "json"
      read_json_by_line = "true"
    }
  }
}

Mysql-CDC -> Jdbc-Postgres

env {
  # You can set engine configuration here
  parallelism = 5
  job.mode = "STREAMING"
  checkpoint.interval = 5000
  read_limit.bytes_per_second=7000000
  read_limit.rows_per_second=400
}

source {
  MySQL-CDC {
    server-id = 5652-5657
    username = "st_user_source"
    password = "mysqlpw"
    table-names = ["shop.products"]
    base-url = "jdbc:mysql://mysql_cdc_e2e:3306/shop"

    schema-changes.enabled = true
  }
}

sink {
  jdbc {
    url = "jdbc:postgresql://postgresql:5432/shop"
    driver = "org.postgresql.Driver"
    user = "postgres"
    password = "postgres"
    generate_sink_sql = true
    database = shop
    table = "public.sink_table_with_schema_change"
    primary_keys = ["id"]

    # Validate ddl update for sink writer multi replica
    multi_table_sink_replica = 2
  }
}