lookup join 使用缓存参数和不使用缓存参数的执行前后对比

0.先看结论

bash 复制代码

#缓存开启参数，默认关闭
  'lookup.cache.max-rows' = '1000',  -- 设置最大缓存条目数为 1000
  'lookup.cache.ttl' = '10 min'     -- 设置缓存条目的最大存活时间为 10 分钟

启用缓存

查询时性能较高，因为数据直接从缓存中读取。
缓存未过期时，MySQL 的查询负载较低。
适用于维表数据变化较少的场景。

不启用缓存

每次查询都会访问 MySQL，性能取决于 MySQL 查询效率。
MySQL 负载较高，不适合高频查询场景。

1.kafka准备工作

bash 复制代码

#(1)启动zk
[root@node1 server]# /export/server/zookeeper/bin/zkServer.sh start

#确认 Zookeeper 是否在 2181 端口监听：
[root@node1 server]# netstat -tulnp | grep 2181
tcp6       0      0 :::2181                 :::*                    LISTEN      4651/java  

结果显示在监听中，没问题

#(2)启动kafka
[root@node1 bin]# cd /export/server/kafka/bin
[root@node1 bin]# kafka-server-start.sh -daemon /export/server/kafka/config/server.properties
[root@node1 bin]# netstat -tulnp | grep 9092
tcp6       0      0 192.168.77.161:9092     :::*                    LISTEN      23613/java    

结果显示在监听中，没问题

#(3)创建topic
[root@node1 bin]# kafka-topics.sh --create \
    --bootstrap-server node1:9092 \
    --replication-factor 1 \
    --partitions 1 \
    --topic orders_topic

#检查是否创建成功
[root@node1 bin]# ./kafka-topics.sh --bootstrap-server node1:9092 --list | grep orders_topic
orders_topic

有显示表示创建成功

#(4)生产数据
[root@node1 bin]# cd /export/server/kafka/bin
[root@node1 bin]# kafka-console-producer.sh --broker-list node1:9092 --topic orders_topic

{"order_id": 1, "customer_id": 101, "order_time": "2024-01-01 10:00:00"}
{"order_id": 2, "customer_id": 102, "order_time": "2024-01-01 10:05:00"}
{"order_id": 3, "customer_id": 103, "order_time": "2024-01-01 10:10:00"}


#(5)测试kafka消费数据
/export/server/kafka/bin/kafka-console-consumer.sh --bootstrap-server node1:9092 --topic orders_topic --from-beginning
/export/server/kafka/bin/kafka-console-consumer.sh --bootstrap-server node1:9092 --topic orders_topic --group group_test --from-beginning


-----备用-------
#删除kafka toopic
/export/server/kafka/bin/kafka-topics.sh --delete --topic orders_topic --bootstrap-server node1:9092
#重新创建相同的 Topic：
/export/server/kafka/bin/kafka-topics.sh --create --topic orders_topic --bootstrap-server node1:9092 --partitions 1 --replication-factor 1

------------

2.mysql准备工作

bash 复制代码

#创建表 和插入数据
CREATE DATABASE IF NOT EXISTS test;
USE test;

CREATE TABLE dim_customer (
    customer_id BIGINT PRIMARY KEY,
    customer_name VARCHAR(255)
);


INSERT INTO dim_customer (customer_id, customer_name) VALUES
(101, 'Alice'),
(102, 'Bob'),
(103, 'Charlie');

3.flinksql

bash 复制代码

#hadoop，我的checkpoint 数据是存hdfs的，所以要启动
start-dfs.sh

#启动flink
cd /export/server/flink
bin/start-cluster.sh

#启动flink sql客户端
sql-client.sh

sql 复制代码

#创建一个从 Kafka 读取订单流数据的表
CREATE TABLE orders (
    order_id BIGINT,
    customer_id BIGINT,
    order_time TIMESTAMP(3),
    proc_time AS PROCTIME() -- 定义 Processing Time
) WITH (
    'connector' = 'kafka',
    'topic' = 'orders_topic',
    'properties.bootstrap.servers' = 'node1:9092',
    'properties.group.id' = 'flink_group',
    'format' = 'json',
    'scan.startup.mode' = 'earliest-offset'
);


select * from orders limit 5;

#创建一个从 MySQL 查询客户信息的维表：
CREATE TABLE dim_customer (
    customer_id BIGINT,
    customer_name STRING,
    PRIMARY KEY (customer_id) NOT ENFORCED
) WITH (
    'connector' = 'jdbc',
    'url' = 'jdbc:mysql://node1:3306/test',
    'table-name' = 'dim_customer',
    'username' = 'root',
    'password' = '123456',
    'lookup.cache.max-rows' = '1000',  -- 最大缓存行数
    'lookup.cache.ttl' = '10 min'     -- 缓存有效时间为 10 分钟
);
select * from dim_customer;

#实现订单流与客户信息的 Lookup Join：
SELECT
    o.order_id,
    o.customer_id,
    c.customer_name,
    o.order_time
FROM orders AS o
LEFT JOIN dim_customer FOR SYSTEM_TIME AS OF o.proc_time AS c
ON o.customer_id = c.customer_id;


---------不启动缓存查询---------
CREATE TABLE dim_customer_no_cache (
    customer_id BIGINT,
    customer_name STRING,
    PRIMARY KEY (customer_id) NOT ENFORCED
) WITH (
    'connector' = 'jdbc',
    'url' = 'jdbc:mysql://node1:3306/test',
    'table-name' = 'dim_customer',
    'username' = 'root',
    'password' = '123456'
);

SELECT
    o.order_id,
    o.customer_id,
    c.customer_name,
    o.order_time
FROM orders AS o
LEFT JOIN dim_customer_no_cache FOR SYSTEM_TIME AS OF o.order_time AS c
ON o.customer_id = c.customer_id;

sql 复制代码

更新维表数据（在查询过程中）：

UPDATE dim_customer SET customer_name = 'Alice Updated' WHERE customer_id = 101;
UPDATE dim_customer SET customer_name = 'Bob Updated' WHERE customer_id = 102;

bash 复制代码

1. 启用缓存
表现：
(1)如果缓存未过期，查询结果不会反映 dim_customer 表的实时更新。
(2)更新 dim_customer 后，直到缓存失效（TTL 到期），才会刷新缓存并获取最新数据。
(3)预期结果如下
初始查询结果：无变化
+------------+-------------+---------------+---------------------+
| order_id   | customer_id | customer_name | order_time          |
+------------+-------------+---------------+---------------------+
| 1          | 101         | Alice         | 2024-01-01 10:00:00 |
| 2          | 102         | Bob           | 2024-01-01 10:05:00 |
| 3          | 103         | Charlie       | 2024-01-01 10:10:00 |
+------------+-------------+---------------+---------------------+

更新 dim_customer 后（缓存未过期）：无变化
+------------+-------------+---------------+---------------------+
| order_id   | customer_id | customer_name | order_time          |
+------------+-------------+---------------+---------------------+
| 1          | 101         | Alice         | 2024-01-01 10:00:00 |
| 2          | 102         | Bob           | 2024-01-01 10:05:00 |
| 3          | 103         | Charlie       | 2024-01-01 10:10:00 |
+------------+-------------+---------------+---------------------+
缓存过期后（10 分钟 TTL 到期）：更新了
+------------+-------------+------------------+---------------------+
| order_id   | customer_id | customer_name    | order_time          |
+------------+-------------+------------------+---------------------+
| 1          | 101         | Alice Updated    | 2024-01-01 10:00:00 |
| 2          | 102         | Bob Updated      | 2024-01-01 10:05:00 |
| 3          | 103         | Charlie          | 2024-01-01 10:10:00 |
+------------+-------------+------------------+---------------------+
------------------------------------------------------------------------------------
2. 不启用缓存
表现：
(1)每次查询都会直接访问 MySQL，查询结果能够实时反映 dim_customer 表的最新数据。
(2)实时性强，但性能可能较差。
(3)预期结果如下： 

初始查询结果：
+------------+-------------+---------------+---------------------+
| order_id   | customer_id | customer_name | order_time          |
+------------+-------------+---------------+---------------------+
| 1          | 101         | Alice         | 2024-01-01 10:00:00 |
| 2          | 102         | Bob           | 2024-01-01 10:05:00 |
| 3          | 103         | Charlie       | 2024-01-01 10:10:00 |
+------------+-------------+---------------+---------------------+

更新 dim_customer 后：
+------------+-------------+------------------+---------------------+
| order_id   | customer_id | customer_name    | order_time          |
+------------+-------------+------------------+---------------------+
| 1          | 101         | Alice Updated    | 2024-01-01 10:00:00 |
| 2          | 102         | Bob Updated      | 2024-01-01 10:05:00 |
| 3          | 103         | Charlie          | 2024-01-01 10:10:00 |
+------------+-------------+------------------+---------------------+