flink postgresql cdc实时同步（含pg安装配置等）

要使用Flink进行PostgreSQL的CDC实时同步，你需要安装并配置PostgreSQL数据库，并确保启用了逻辑复制(也称为逻辑解码)。以下是基本步骤：

1. 安装PostgreSQL：

   • 在你的系统上安装PostgreSQL 10或更高版本。
   • 确保数据库用户具有适当的权限，并可以进行逻辑复制。

2. 配置PostgreSQL的逻辑复制：

   • 修改postgresql.conf文件，设置以下参数：

     
     
     
     wal_level = logical
     max_wal_senders = 3  # 根据需要设置
     max_replication_slots = 3  # 根据需要设置

   • 重启PostgreSQL服务以应用更改。

   • 创建逻辑复制插槽：

     
     
     
     SELECT * FROM pg_create_logical_replication_slot('flink_slot', 'test_decoding');

3. 在Flink中设置CDC源连接PostgreSQL：

   • 使用Flink提供的JDBC连接器来连接PostgreSQL。
   • 使用Flink CDC库来处理变更数据捕获。

以下是一个简化的示例代码，展示如何使用Flink的Table API配置CDC源：

import org.apache.flink.streaming.api.environment.StreamExecutionEnvironment;
import org.apache.flink.table.api.bridge.java.StreamTableEnvironment;
import org.apache.flink.table.api.*;
import org.apache.flink.table.planner.factories.TestFormatFactory;
 
public class PgCdcExample {
    public static void main(String[] args) throws Exception {
        StreamExecutionEnvironment env = StreamExecutionEnvironment.getExecutionEnvironment();
        StreamTableEnvironment tableEnv = StreamTableEnvironment.create(env);
 
        String sourceDDL = "" +
                "CREATE TABLE pg_source (" +
                "   id INT," +
                "   name STRING," +
                "   price DECIMAL(32, 2)" +
                ") WITH (" +
                "   'connector' = 'postgres-cdc'," +
                "   'hostname' = 'your_postgresql_host'," +
                "   'port' = '5432'," +
                "   'username' = 'your_username'," +
                "   'password' = 'your_password'," +
                "   'database-name' = 'your_db_name'," +
                "   'schema-name' = 'your_schema_name'," +
                "   'table-name' = 'your_table_name'," +
                "   'scan.startup.mode' = 'latest-offset'" +
                ")";
 
        tableEnv.executeSql(sourceDDL);
 
        // 定义sink（例如Kafka，Elasticsearch等）
        String sinkDDL = "" +
                "CREATE TABLE kafka_sink (" +
                "   id INT," +
                "   name STRING," +
                "   price DECIMAL(32, 2)" +
                ") WITH (" +
                "   'connector' = '...'," + // 指定Kafka连接器
                "   ..." + // Kafka连接器参数
                ")";