1.Flink cdc 概念
CDC 的全称是 Change Data Capture ，在广义的概念上，只要能捕获数据变更的技术，我们都可以称为 CDC 。通常我们说的 CDC 技术主要面向
数据库的变更，是一种用于捕获数据库中数据变更的技术。
2.应用场景
1. 数据同步，用于备份，容灾
2. 数据分发，一个数据源分发给多个下游
3. 数据采集(E)，面向数据仓库/数据湖的 ETL 数据集成
3.cdc 技术
目前业界主流的实现机制的可以分为两种：
1.基于查询的 CDC
a.离线调度查询作业，批处理。
b.无法保障数据一致性。
c.不保障实时性。
2.基于日志的 CDC
a.实时消费日志，流处理。
b.保障数据一致性。
c.提供实时数据。
4.常见的开源cdc 方案
5. source 官网
https://github.com/ververica/flink-cdc-connectors
6. 支持的连接
| Database | Version |
|---|---|
| MySQL | Database: 5.7, 8.0.x JDBC Driver: 8.0.16 |
| PostgreSQL | Database: 9.6, 10, 11, 12 JDBC Driver: 42.2.12 |
| MongoDB | Database: 4.0, 4.2, 5.0MongoDB Driver: 4.3.1 |
7.pom 文件
<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<parent>
<artifactId>Flink-learning</artifactId>
<groupId>com.wudl.flink</groupId>
<version>1.0-SNAPSHOT</version>
</parent>
<modelVersion>4.0.0</modelVersion>
<artifactId>Flink-cdc2.0</artifactId>
<properties>
<flink-version>1.13.0</flink-version>
<maven.compiler.source>1.8</maven.compiler.source>
<maven.compiler.target>1.8</maven.compiler.target>
</properties>
<dependencies>
<dependency>
<groupId>org.projectlombok</groupId>
<artifactId>lombok</artifactId>
<version>1.18.2</version>
<scope>provided</scope>
</dependency>
<dependency>
<groupId>org.apache.flink</groupId>
<artifactId>flink-java</artifactId>
<version>${flink-version}</version>
</dependency>
<dependency>
<groupId>org.apache.flink</groupId>
<artifactId>flink-streaming-java_2.12</artifactId>
<version>${flink-version}</version>
</dependency>
<dependency>
<groupId>org.apache.flink</groupId>
<artifactId>flink-clients_2.12</artifactId>
<version>${flink-version}</version>
</dependency>
<dependency>
<groupId>org.apache.hadoop</groupId>
<artifactId>hadoop-client</artifactId>
<version>3.1.3</version>
</dependency>
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<version>5.1.49</version>
</dependency>
<dependency>
<groupId>org.apache.flink</groupId>
<artifactId>flink-table-planner-blink_2.12</artifactId>
<version>${flink-version}</version>
</dependency>
<dependency>
<groupId>com.ververica</groupId>
<!-- add the dependency matching your database -->
<artifactId>flink-connector-mysql-cdc</artifactId>
<version>2.0.2</version>
</dependency>
<dependency>
<groupId>com.alibaba</groupId>
<artifactId>fastjson</artifactId>
<version>1.2.75</version>
</dependency>
</dependencies>
<build>
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-assembly-plugin</artifactId>
<version>3.0.0</version>
<configuration>
<descriptorRefs>
<descriptorRef>jar-with-dependencies</descriptorRef>
</descriptorRefs>
</configuration>
<executions>
<execution>
<id>make-assembly</id>
<phase>package</phase>
<goals>
<goal>single</goal>
</goals>
</execution>
</executions>
</plugin>
</plugins>
</build>
</project>
8. 代码
package com.wud.cdc2;
import com.ververica.cdc.connectors.mysql.MySqlSource;
import com.ververica.cdc.connectors.mysql.table.StartupOptions;
import com.ververica.cdc.debezium.DebeziumDeserializationSchema;
import com.ververica.cdc.debezium.DebeziumSourceFunction;
import com.ververica.cdc.debezium.StringDebeziumDeserializationSchema;
import org.apache.flink.runtime.state.filesystem.FsStateBackend;
import org.apache.flink.streaming.api.CheckpointingMode;
import org.apache.flink.streaming.api.datastream.DataStreamSource;
import org.apache.flink.streaming.api.environment.CheckpointConfig;
import org.apache.flink.streaming.api.environment.StreamExecutionEnvironment;
import org.apache.flink.streaming.api.environment.StreamPipelineOptions;
import org.apache.flink.table.api.Table;
import org.apache.flink.table.api.bridge.java.StreamTableEnvironment;
import org.apache.flink.types.Row;
import static org.apache.flink.table.api.Expressions.$;
/**
* @ClassName : FlinkCdc
* @Description :
* @Author :wudl
* @Date: 2021-10-02 20:15
*/
public class FlinkCDC {
public static void main(String[] args) throws Exception {
StreamExecutionEnvironment env = StreamExecutionEnvironment.getExecutionEnvironment();
env.setParallelism(1);
StreamTableEnvironment tabEnv = StreamTableEnvironment.create(env);
env.enableCheckpointing(5000L);
env.getCheckpointConfig().setCheckpointingMode(CheckpointingMode.EXACTLY_ONCE);
// 设置任务关闭时候保留最后一次checkpoint 的数据
env.getCheckpointConfig().enableExternalizedCheckpoints(CheckpointConfig.ExternalizedCheckpointCleanup.RETAIN_ON_CANCELLATION);
// 指定ck 的自动重启策略
env.setStateBackend(new FsStateBackend("hdfs://192.168.1.161:8020/cdc2.0-test/ck"));
// 设置hdfs 的访问用户名
System.setProperty("HADOOP_USER_NAME","hdfs");
DebeziumSourceFunction<String> mySqlSource = MySqlSource.<String>builder()
.hostname("192.168.1.180")
.port(3306)
.username("root")
.password("123456")
.databaseList("test")
.tableList("test.Flink_iceberg")
.deserializer(new StringDebeziumDeserializationSchema())
.startupOptions(StartupOptions.initial())
.build();
DataStreamSource<String> dataStreamSource = env.addSource(mySqlSource);
dataStreamSource.print();
env.execute();
}
}
9执行结果
SourceRecord{sourcePartition={server=mysql_binlog_source}, sourceOffset={ts_sec=1633178585, file=mysql-bin.000036, pos=765, snapshot=true}} ConnectRecord{topic='mysql_binlog_source.test.Flink_iceberg', kafkaPartition=null, key=null, keySchema=null, value=Struct{after=Struct{id=10011,name=flink-mysql,age=19,dt=2021-09-24},source=Struct{version=1.5.2.Final,connector=mysql,name=mysql_binlog_source,ts_ms=1633178585007,snapshot=true,db=test,table=Flink_iceberg,server_id=0,file=mysql-bin.000036,pos=765,row=0},op=r,ts_ms=1633178585013}, valueSchema=Schema{mysql_binlog_source.test.Flink_iceberg.Envelope:STRUCT}, timestamp=null, headers=ConnectHeaders(headers=)}
SourceRecord{sourcePartition={server=mysql_binlog_source}, sourceOffset={ts_sec=1633178585, file=mysql-bin.000036, pos=765, snapshot=true}} ConnectRecord{topic='mysql_binlog_source.test.Flink_iceberg', kafkaPartition=null, key=null, keySchema=null, value=Struct{after=Struct{id=10012,name=flink-mysqA,age=19,dt=2021-09-24},source=Struct{version=1.5.2.Final,connector=mysql,name=mysql_binlog_source,ts_ms=1633178585015,snapshot=true,db=test,table=Flink_iceberg,server_id=0,file=mysql-bin.000036,pos=765,row=0},op=r,ts_ms=1633178585016}, valueSchema=Schema{mysql_binlog_source.test.Flink_iceberg.Envelope:STRUCT}, timestamp=null, headers=ConnectHeaders(headers=)}
SourceRecord{sourcePartition={server=mysql_binlog_source}, sourceOffset={ts_sec=1633178585, file=mysql-bin.000036, pos=765, snapshot=true}} ConnectRecord{topic='mysql_binlog_source.test.Flink_iceberg', kafkaPartition=null, key=null, keySchema=null, value=Struct{after=Struct{id=10012,name=flink-mysqA,age=19,dt=2021-09-24},source=Struct{version=1.5.2.Final,connector=mysql,name=mysql_binlog_source,ts_ms=1633178585017,snapshot=true,db=test,table=Flink_iceberg,server_id=0,file=mysql-bin.000036,pos=765,row=0},op=r,ts_ms=1633178585017}, valueSchema=Schema{mysql_binlog_source.test.Flink_iceberg.Envelope:STRUCT}, timestamp=null, headers=ConnectHeaders(headers=)}
SourceRecord{sourcePartition={server=mysql_binlog_source}, sourceOffset={ts_sec=1633178585, file=mysql-bin.000036, pos=765, snapshot=true}} ConnectRecord{topic='mysql_binlog_source.test.Flink_iceberg', kafkaPartition=null, key=null, keySchema=null, value=Struct{after=Struct{id=10011,name=flink-mysql,age=19,dt=2021-09-24},source=Struct{version=1.5.2.Final,connector=mysql,name=mysql_binlog_source,ts_ms=1633178585017,snapshot=true,db=test,table=Flink_iceberg,server_id=0,file=mysql-bin.000036,pos=765,row=0},op=r,ts_ms=1633178585017}, valueSchema=Schema{mysql_binlog_source.test.Flink_iceberg.Envelope:STRUCT}, timestamp=null, headers=ConnectHeaders(headers=)}
SourceRecord{sourcePartition={server=mysql_binlog_source}, sourceOffset={ts_sec=1633178585, file=mysql-bin.000036, pos=765, snapshot=true}} ConnectRecord{topic='mysql_binlog_source.test.Flink_iceberg', kafkaPartition=null, key=null, keySchema=null, value=Struct{after=Struct{id=10011,name=flink-mysql,age=19,dt=2021-09-24},source=Struct{version=1.5.2.Final,connector=mysql,name=mysql_binlog_source,ts_ms=1633178585017,snapshot=true,db=test,table=Flink_iceberg,server_id=0,file=mysql-bin.000036,pos=765,row=0},op=r,ts_ms=1633178585017}, valueSchema=Schema{mysql_binlog_source.test.Flink_iceberg.Envelope:STRUCT}, timestamp=null, headers=ConnectHeaders(headers=)}
SourceRecord{sourcePartition={server=mysql_binlog_source}, sourceOffset={ts_sec=1633178585, file=mysql-bin.000036, pos=765, snapshot=true}} ConnectRecord{topic='mysql_binlog_source.test.Flink_iceberg', kafkaPartition=null, key=null, keySchema=null, value=Struct{after=Struct{id=10012,name=flink-mysqA,age=19,dt=2021-09-24},source=Struct{version=1.5.2.Final,connector=mysql,name=mysql_binlog_source,ts_ms=1633178585017,snapshot=true,db=test,table=Flink_iceberg,server_id=0,file=mysql-bin.000036,pos=765,row=0},op=r,ts_ms=1633178585017}, valueSchema=Schema{mysql_binlog_source.test.Flink_iceberg.Envelope:STRUCT}, timestamp=null, headers=ConnectHeaders(headers=)}
SourceRecord{sourcePartition={server=mysql_binlog_source}, sourceOffset={ts_sec=1633178585, file=mysql-bin.000036, pos=765, snapshot=true}} ConnectRecord{topic='mysql_binlog_source.test.Flink_iceberg', kafkaPartition=null, key=null, keySchema=null, value=Struct{after=Struct{id=10013,name=flink-mysqA3,age=19,dt=2021-09-24},source=Struct{version=1.5.2.Final,connector=mysql,name=mysql_binlog_source,ts_ms=1633178585017,snapshot=true,db=test,table=Flink_iceberg,server_id=0,file=mysql-bin.000036,pos=765,row=0},op=r,ts_ms=1633178585017}, valueSchema=Schema{mysql_binlog_source.test.Flink_iceberg.Envelope:STRUCT}, timestamp=null, headers=ConnectHeaders(headers=)}
SourceRecord{sourcePartition={server=mysql_binlog_source}, sourceOffset={ts_sec=1633178585, file=mysql-bin.000036, pos=765, snapshot=true}} ConnectRecord{topic='mysql_binlog_source.test.Flink_iceberg', kafkaPartition=null, key=null, keySchema=null, value=Struct{after=Struct{id=10014,name=flink-mysqA4,age=19,dt=2021-09-28},source=Struct{version=1.5.2.Final,connector=mysql,name=mysql_binlog_source,ts_ms=1633178585017,snapshot=true,db=test,table=Flink_iceberg,server_id=0,file=mysql-bin.000036,pos=765,row=0},op=r,ts_ms=1633178585017}, valueSchema=Schema{mysql_binlog_source.test.Flink_iceberg.Envelope:STRUCT}, timestamp=null, headers=ConnectHeaders(headers=)}
SourceRecord{sourcePartition={server=mysql_binlog_source}, sourceOffset={ts_sec=1633178585, file=mysql-bin.000036, pos=765, snapshot=true}} ConnectRecord{topic='mysql_binlog_source.test.Flink_iceberg', kafkaPartition=null, key=null, keySchema=null, value=Struct{after=Struct{id=10011,name=flink-mysql,age=19,dt=2021-09-24},source=Struct{version=1.5.2.Final,connector=mysql,name=mysql_binlog_source,ts_ms=1633178585017,snapshot=true,db=test,table=Flink_iceberg,server_id=0,file=mysql-bin.000036,pos=765,row=0},op=r,ts_ms=1633178585017}, valueSchema=Schema{mysql_binlog_source.test.Flink_iceberg.Envelope:STRUCT}, timestamp=null, headers=ConnectHeaders(headers=)}
SourceRecord{sourcePartition={server=mysql_binlog_source}, sourceOffset={ts_sec=1633178585, file=mysql-bin.000036, pos=765, snapshot=true}} ConnectRecord{topic='mysql_binlog_source.test.Flink_iceberg', kafkaPartition=null, key=null, keySchema=null, value=Struct{after=Struct{id=10012,name=flink-mysqA,age=19,dt=2021-09-24},source=Struct{version=1.5.2.Final,connector=mysql,name=mysql_binlog_source,ts_ms=1633178585017,snapshot=true,db=test,table=Flink_iceberg,server_id=0,file=mysql-bin.000036,pos=765,row=0},op=r,ts_ms=1633178585018}, valueSchema=Schema{mysql_binlog_source.test.Flink_iceberg.Envelope:STRUCT}, timestamp=null, headers=ConnectHeaders(headers=)}
SourceRecord{sourcePartition={server=mysql_binlog_source}, sourceOffset={ts_sec=1633178585, file=mysql-bin.000036, pos=765, snapshot=true}} ConnectRecord{topic='mysql_binlog_source.test.Flink_iceberg', kafkaPartition=null, key=null, keySchema=null, value=Struct{after=Struct{id=10012,name=flink-mysqA,age=19,dt=2021-09-24},source=Struct{version=1.5.2.Final,connector=mysql,name=mysql_binlog_source,ts_ms=1633178585018,snapshot=true,db=test,table=Flink_iceberg,server_id=0,file=mysql-bin.000036,pos=765,row=0},op=r,ts_ms=1633178585018}, valueSchema=Schema{mysql_binlog_source.test.Flink_iceberg.Envelope:STRUCT}, timestamp=null, headers=ConnectHeaders(headers=)}
SourceRecord{sourcePartition={server=mysql_binlog_source}, sourceOffset={ts_sec=1633178585, file=mysql-bin.000036, pos=765, snapshot=true}} ConnectRecord{topic='mysql_binlog_source.test.Flink_iceberg', kafkaPartition=null, key=null, keySchema=null, value=Struct{after=Struct{id=10011,name=flink-mysql,age=19,dt=2021-09-24},source=Struct{version=1.5.2.Final,connector=mysql,name=mysql_binlog_source,ts_ms=1633178585018,snapshot=true,db=test,table=Flink_iceberg,server_id=0,file=mysql-bin.000036,pos=765,row=0},op=r,ts_ms=1633178585018}, valueSchema=Schema{mysql_binlog_source.test.Flink_iceberg.Envelope:STRUCT}, timestamp=null, headers=ConnectHeaders(headers=)}
SourceRecord{sourcePartition={server=mysql_binlog_source}, sourceOffset={ts_sec=1633178585, file=mysql-bin.000036, pos=765, snapshot=true}} ConnectRecord{topic='mysql_binlog_source.test.Flink_iceberg', kafkaPartition=null, key=null, keySchema=null, value=Struct{after=Struct{id=10011,name=flink-mysql,age=19,dt=2021-09-24},source=Struct{version=1.5.2.Final,connector=mysql,name=mysql_binlog_source,ts_ms=1633178585018,snapshot=true,db=test,table=Flink_iceberg,server_id=0,file=mysql-bin.000036,pos=765,row=0},op=r,ts_ms=1633178585018}, valueSchema=Schema{mysql_binlog_source.test.Flink_iceberg.Envelope:STRUCT}, timestamp=null, headers=ConnectHeaders(headers=)}
SourceRecord{sourcePartition={server=mysql_binlog_source}, sourceOffset={ts_sec=1633178585, file=mysql-bin.000036, pos=765, snapshot=true}} ConnectRecord{topic='mysql_binlog_source.test.Flink_iceberg', kafkaPartition=null, key=null, keySchema=null, value=Struct{after=Struct{id=10012,name=flink-mysqA,age=19,dt=2021-09-24},source=Struct{version=1.5.2.Final,connector=mysql,name=mysql_binlog_source,ts_ms=1633178585018,snapshot=true,db=test,table=Flink_iceberg,server_id=0,file=mysql-bin.000036,pos=765,row=0},op=r,ts_ms=1633178585018}, valueSchema=Schema{mysql_binlog_source.test.Flink_iceberg.Envelope:STRUCT}, timestamp=null, headers=ConnectHeaders(headers=)}
SourceRecord{sourcePartition={server=mysql_binlog_source}, sourceOffset={ts_sec=1633178585, file=mysql-bin.000036, pos=765, snapshot=true}} ConnectRecord{topic='mysql_binlog_source.test.Flink_iceberg', kafkaPartition=null, key=null, keySchema=null, value=Struct{after=Struct{id=10013,name=flink-mysqA3,age=19,dt=2021-09-24},source=Struct{version=1.5.2.Final,connector=mysql,name=mysql_binlog_source,ts_ms=1633178585018,snapshot=true,db=test,table=Flink_iceberg,server_id=0,file=mysql-bin.000036,pos=765,row=0},op=r,ts_ms=1633178585018}, valueSchema=Schema{mysql_binlog_source.test.Flink_iceberg.Envelope:STRUCT}, timestamp=null, headers=ConnectHeaders(headers=)}
SourceRecord{sourcePartition={server=mysql_binlog_source}, sourceOffset={ts_sec=1633178585, file=mysql-bin.000036, pos=765, snapshot=true}} ConnectRecord{topic='mysql_binlog_source.test.Flink_iceberg', kafkaPartition=null, key=null, keySchema=null, value=Struct{after=Struct{id=10014,name=flink-mysqA4,age=19,dt=2021-09-28},source=Struct{version=1.5.2.Final,connector=mysql,name=mysql_binlog_source,ts_ms=1633178585018,snapshot=true,db=test,table=Flink_iceberg,server_id=0,file=mysql-bin.000036,pos=765,row=0},op=r,ts_ms=1633178585018}, valueSchema=Schema{mysql_binlog_source.test.Flink_iceberg.Envelope:STRUCT}, timestamp=null, headers=ConnectHeaders(headers=)}
SourceRecord{sourcePartition={server=mysql_binlog_source}, sourceOffset={ts_sec=1633178585, file=mysql-bin.000036, pos=765}} ConnectRecord{topic='mysql_binlog_source.test.Flink_iceberg', kafkaPartition=null, key=null, keySchema=null, value=Struct{after=Struct{id=10050,name=flink-cdc-add,age=21,dt=2021-10-2},source=Struct{version=1.5.2.Final,connector=mysql,name=mysql_binlog_source,ts_ms=1633178585018,snapshot=last,db=test,table=Flink_iceberg,server_id=0,file=mysql-bin.000036,pos=765,row=0},op=r,ts_ms=1633178585018}, valueSchema=Schema{mysql_binlog_source.test.Flink_iceberg.Envelope:STRUCT}, timestamp=null, headers=ConnectHeaders(headers=)}
10 .集群执行
10.1执行命令
[root@basenode flink-1.13.2]# bin/flink run -c com.wud.cdc2.FlinkCDC /opt/datas/Flink-cdc2.0-1.0-SNAPSHOT-jar-with-dependencies.jar
Job has been submitted with JobID 137b680a6bb934e43568f14f6583b62c
10.2 手动执行savepoint
给当前程序创建保存点-savepoint
[root@basenode flink-1.13.2]# bin/flink savepoint e8e918c2517a777e817c630cf1d6b932 hdfs://192.168.1.161:8020/cdc-test/savepoint
Triggering savepoint for job e8e918c2517a777e817c630cf1d6b932.
Waiting for response...
Savepoint completed. Path: hdfs://192.168.1.161:8020/cdc-test/savepoint/savepoint-e8e918-9ef094f349be
You can resume your program from this savepoint with the run command.
[root@basenode flink-1.13.2]#
10.3 界面停止flink 程序
然后再mysql 中添加数据
10.4 启动flink 程序
执行命令：bin/flink run -s hdfs://192.168.1.161:8020/cdc-test/savepoint/savepoint-e8e918-9ef094f349be -c com.wud.cdc2.FlinkCDC /opt/datas/Flink-cdc2.0-1.0-SNAPSHOT-jar-with-dependencies.jar
[root@basenode flink-1.13.2]# bin/flink run -s hdfs://192.168.1.161:8020/cdc-test/savepoint/savepoint-e8e918-9ef094f349be -c com.wud.cdc2.FlinkCDC /opt/datas/Flink-cdc2.0-1.0-SNAPSHOT-jar-with-dependencies.jar
Job has been submitted with JobID 474a0da99820aa6025203f9806b9fcad
查看日志：
