flink sql lookup join学习demo

flink sql lookup join demo

本文主要是通过一个小的案例，记录使用flinksql lookup join的使用，其中mysql作为lookup join的维表

1.source数据源准备

-- 在mysql中创建表source源表
DROP TABLE IF EXISTS `show_log`;
CREATE TABLE `show_log` (
  `log_id` int(11) NOT NULL,
  `timestamp` datetime DEFAULT NULL,
  `user_id` varchar(255) DEFAULT NULL,
  PRIMARY KEY (`log_id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4;

-- 插入数据
INSERT INTO `show_log` VALUES ('1', '2021-11-01 00:01:03', 'a'), ('2', '2021-11-01 00:03:00', 'b'), ('3', '2021-11-01 00:05:00', 'c'), ('4', '2021-11-01 00:06:00', 'b'), ('5', '2021-11-01 00:07:00', 'c');

2.维表数据准备

-- 在mysql中创建维度表
DROP TABLE IF EXISTS `user_profile`;
CREATE TABLE `user_profile` (
  `user_id` varchar(255) NOT NULL,
  `age` varchar(255) DEFAULT NULL,
  `sex` varchar(255) DEFAULT NULL,
  PRIMARY KEY (`user_id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4;

-- 插入数据
INSERT INTO `user_profile` VALUES ('a', '12-18', '男'), ('b', '18-24', '女'), ('c', '18-24', '男');

3.创建flink映射表

3.1创建source端映射表

CREATE TABLE show_log (
    log_id BIGINT,
    `timestamp` as cast(CURRENT_TIMESTAMP as timestamp(3)),
    user_id STRING,
    proctime AS PROCTIME()
)
WITH (
    'connector' = 'mysql-cdc',
    'hostname' = 'localhost',
    'username' = 'xx',
    'port' = '3306',
    'password' = 'xxx',
    'database-name' = 'flink',
    'table-name' = 'show_log',
    'scan.startup.mode' = 'initial',
    'scan.incremental.snapshot.enabled' = 'false'
);

3.2创建维度映射表

CREATE TABLE user_profile (
    user_id STRING,
    age STRING,
    sex STRING
    ) WITH (
        'connector' = 'jdbc',
        'url' = 'jdbc:mysql://localhost:3306/flink?characterEncoding=UTF8',
        'username' = 'xx',
        'password' = 'xx',
        'table-name' = 'user_profile',
        'lookup.cache.max-rows' = '100',
        'lookup.cache.ttl' = '6000s'
);

3.3创建sink端映射表

-- 使用print connector在flink web ui中打印输出
CREATE TABLE sink_table (
    log_id BIGINT,
    `timestamp` TIMESTAMP(3),
    user_id STRING,
    proctime TIMESTAMP(3),
    age STRING,
    sex STRING
) WITH (
  'connector' = 'print'
);

4sql-client提交

INSERT INTO sink_table
SELECT 
    s.log_id as log_id
    , s.`timestamp` as `timestamp`
    , s.user_id as user_id
    , s.proctime as proctime
    , u.sex as sex
    , u.age as age
FROM show_log AS s
LEFT JOIN user_profile FOR SYSTEM_TIME AS OF s.proctime AS u
ON s.user_id = u.user_id;

5flink web ui查看任务信息

如果任务在运行过程中taskmanager日志有报GC，可查看taskmanager metrics信息，观察对应指标是否打满，从而重新修改对应配置文件的参数重启集群。