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什么是CDC?
CDC是(Change Data Capture 变更数据获取)的简称。核心思想是,监测并捕获数据库的变动(包括数据 或 数据表的插入INSERT、更新UPDATE、删除DELETE等),将这些变更按发生的顺序完整记录下来,写入到消息中间件中以供其他服务进行订阅及消费。

1. 环境准备
-
mysql
-
hbase
-
flink 1.13.5 on yarn
说明:如果没有安装hadoop,那么可以不用yarn,直接用flink standalone环境吧。
2. 下载下列依赖包
下面两个地址下载flink的依赖包,放在lib目录下面。
如果你的Flink是其它版本,可以来这里下载。
我是flink1.13,这里flink-sql-connector-mysql-cdc,需要1.4.0以上版本。

如果你是更高版本的flink,可以自行https://github.com/ververica/flink-cdc-connectors下载新版mvn clean install -DskipTests 自己编译。

这是我编译的最新版2.2,传上去发现太新了,如果重新换个版本,我得去gitee下载源码,不然github速度太慢了,然后用IDEA编译打包,又得下载一堆依赖。我投降,我直接去网上下载了个1.4的直接用了。
我下载的jar包,放在flink的lib目录下面:

flink-sql-connector-hbase-1.4_2.11-1.13.5.jar flink-sql-connector-mysql-cdc-1.4.0.jar
3. 启动flink-sql client
- 先在yarn上面启动一个application,进入flink13.5目录,执行:
bin/yarn-session.sh -d -s 2 -jm 1024 -tm 2048 -qu root.sparkstreaming -nm flink-cdc-hbase
- 进入flink sql命令行
bin/sql-client.sh embedded -s flink-cdc-hbase

4. 同步数据
这里有一张mysql表:
CREATE TABLE `product_view` ( `id` int(11) NOT NULL AUTO_INCREMENT, `user_id` int(11) NOT NULL, `product_id` int(11) NOT NULL, `server_id` int(11) NOT NULL, `duration` int(11) NOT NULL, `times` varchar(11) NOT NULL, `time` datetime NOT NULL, PRIMARY KEY (`id`), KEY `time` (`time`), KEY `user_product` (`user_id`,`product_id`) USING BTREE, KEY `times` (`times`) USING BTREE ) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4; -- 样本数据 INSERT INTO `product_view` VALUES ('1', '1', '1', '1', '120', '120', '2020-04-24 13:14:00'); INSERT INTO `product_view` VALUES ('2', '1', '1', '1', '120', '120', '2020-04-24 13:14:00'); INSERT INTO `product_view` VALUES ('3', '1', '1', '3', '120', '120', '2020-04-24 13:14:00'); INSERT INTO `product_view` VALUES ('4', '1', '1', '2', '120', '120', '2020-04-24 13:14:00'); INSERT INTO `product_view` VALUES ('5', '8', '1', '1', '120', '120', '2020-05-14 13:14:00'); INSERT INTO `product_view` VALUES ('6', '8', '1', '2', '120', '120', '2020-05-13 13:14:00'); INSERT INTO `product_view` VALUES ('7', '8', '1', '3', '120', '120', '2020-04-24 13:14:00'); INSERT INTO `product_view` VALUES ('8', '8', '1', '3', '120', '120', '2020-04-23 13:14:00'); INSERT INTO `product_view` VALUES ('9', '8', '1', '2', '120', '120', '2020-05-13 13:14:00');
- 创建数据表关联mysql
CREATE TABLE product_view_source ( `id` int, `user_id` int, `product_id` int, `server_id` int, `duration` int, `times` string, `time` timestamp, PRIMARY KEY (`id`) NOT ENFORCED ) WITH ( 'connector' = 'mysql-cdc', 'hostname' = '192.168.1.2', 'port' = '3306', 'username' = 'bigdata', 'password' = 'bigdata', 'database-name' = 'test', 'table-name' = 'product_view' );
这样,我们在flink sql client操作这个表相当于操作mysql里面的对应表。
- 创建数据表关联hbase
CREATE TABLE product_view_hbase ( rowkey INT, family1 ROW<user_id INT, product_id INT, server_id INT, duration INT>, PRIMARY KEY (rowkey) NOT ENFORCED ) WITH ( 'connector' = 'hbase-1.4', 'table-name' = 'product_view', 'zookeeper.quorum' = 'cdh-001:2181' );
这里,需要提前在hbase里面创建好product_view这个主题。
- 同步数据

建立同步任务,可以使用sql如下:
insert into product_view_hbase select id as rowkey, ROW(user_id, product_id, server_id, duration) from product_view_source;
这个时候是可以退出flink sql-client的,然后进入flink web-ui,可以看到mysql表数据已经同步到hbase中了,对mysql进行插入,hbase都是同步更新的。
进入hbase shell,可以看到数据已经从mysql同步到hbase了:
hbase(main):009:0> scan 'product_view' ROW COLUMN+CELL x00x00x00x01 column=family1:duration, timestamp=1663223736391, value=x00x00x00x x00x00x00x01 column=family1:product_id, timestamp=1663223736391, value=x00x00x00x01 x00x00x00x01 column=family1:server_id, timestamp=1663223736391, value=x00x00x00x01 x00x00x00x01 column=family1:user_id, timestamp=1663223736391, value=x00x00x00x01 x00x00x00x02 column=family1:duration, timestamp=1663223736391, value=x00x00x00x x00x00x00x02 column=family1:product_id, timestamp=1663223736391, value=x00x00x00x01 x00x00x00x02 column=family1:server_id, timestamp=1663223736391, value=x00x00x00x01 x00x00x00x02 column=family1:user_id, timestamp=1663223736391, value=x00x00x00x01 x00x00x00x03 column=family1:duration, timestamp=1663223736391, value=x00x00x00x x00x00x00x03 column=family1:product_id, timestamp=1663223736391, value=x00x00x00x01 x00x00x00x03 column=family1:server_id, timestamp=1663223736391, value=x00x00x00x03 x00x00x00x03 column=family1:user_id, timestamp=1663223736391, value=x00x00x00x01 x00x00x00x04 column=family1:duration, timestamp=1663223736391, value=x00x00x00x x00x00x00x04 column=family1:product_id, timestamp=1663223736391, value=x00x00x00x01 x00x00x00x04 column=family1:server_id, timestamp=1663223736391, value=x00x00x00x02 x00x00x00x04 column=family1:user_id, timestamp=1663223736391, value=x00x00x00x01 x00x00x00x05 column=family1:duration, timestamp=1663223736391, value=x00x00x00x x00x00x00x05 column=family1:product_id, timestamp=1663223736391, value=x00x00x00x01 x00x00x00x05 column=family1:server_id, timestamp=1663223736391, value=x00x00x00x01 x00x00x00x05 column=family1:user_id, timestamp=1663223736391, value=x00x00x00x08 x00x00x00x06 column=family1:duration, timestamp=1663223736391, value=x00x00x00x x00x00x00x06 column=family1:product_id, timestamp=1663223736391, value=x00x00x00x01 x00x00x00x06 column=family1:server_id, timestamp=1663223736391, value=x00x00x00x02 x00x00x00x06 column=family1:user_id, timestamp=1663223736391, value=x00x00x00x08 x00x00x00x07 column=family1:duration, timestamp=1663223736391, value=x00x00x00x x00x00x00x07 column=family1:product_id, timestamp=1663223736391, value=x00x00x00x01 x00x00x00x07 column=family1:server_id, timestamp=1663223736391, value=x00x00x00x03 x00x00x00x07 column=family1:user_id, timestamp=1663223736391, value=x00x00x00x08 x00x00x00x09 column=family1:duration, timestamp=1663223736391, value=x00x00x00x x00x00x00x09 column=family1:product_id, timestamp=1663223736391, value=x00x00x00x01 x00x00x00x09 column=family1:server_id, timestamp=1663223736391, value=x00x00x00x03 x00x00x00x09 column=family1:user_id, timestamp=1663223736391, value=x00x00x00x08 x00x00x00x0A column=family1:duration, timestamp=1663223736391, value=x00x00x00x x00x00x00x0A column=family1:product_id, timestamp=1663223736391, value=x00x00x00x01 x00x00x00x0A column=family1:server_id, timestamp=1663223736391, value=x00x00x00x02 x00x00x00x0A column=family1:user_id, timestamp=1663223736391, value=x00x00x00x08 9 row(s) Took 0.1656 seconds
直接在flink-sql client里面查询hbase数据,也是可以的:
Flink SQL> select * from product_view_hbase ; 2022-09-15 15:38:23,205 INFO org.apache.flink.yarn.YarnClusterDescriptor [] - No path for the flink jar passed. Using the location of class org.apache.flink.yarn.YarnClusterDescriptor to locate the jar 2022-09-15 15:38:23,207 INFO org.apache.hadoop.yarn.client.ConfiguredRMFailoverProxyProvider [] - Failing over to rm72 2022-09-15 15:38:23,212 INFO org.apache.flink.yarn.YarnClusterDescriptor [] - Found Web Interface cdh-001:35225 of application 'application_1633924491541_7321'.
执行上面查询sql,就会进入界面,这就是hbase里面的数据了:

5. 关联查询
在这个flink-sql client环境中,这里有两张表:product_view_source(mysql的表)和product_view_hbase(hbase的表),后者是有前者查询导入的,这里为了简单,我没有再关联其它第三张表,就用这两张表,做关联查询,达到演示的目的。
select product_view_source.*, product_view_hbase.* from product_view_source inner join product_view_hbase on product_view_source.id = product_view_hbase.rowkey;
这里做了个简单的关联查询,通过id跟rowkey关联,然后打开web-ui,通过flink web-ui结果可以看出,这里是个hash join,两个source,到join,一共3个task。

看看查出来的结果吧,这是flnk-sql client:

比如我选中这一行,进来后是这条数据的详细情况,是没有问题的:

参考资料
https://nightlies.apache.org/flink/flink-docs-release-1.13/zh/docs/connectors/table/hbase/