flink sql join hbase demo

lookup join mysql demo：  flink lookup join mysql demo

## join rowkey

-- Lookup Source
-- kafka source
CREATE TABLE user_log (
user_id STRING
,item_id STRING
,category_id STRING
,behavior STRING
,ts TIMESTAMP(3)
,process_time as proctime()
, WATERMARK FOR ts AS ts - INTERVAL '5' SECOND
) WITH (
'connector' = 'kafka'
,'topic' = 'user_behavior'
,'properties.bootstrap.servers' = 'localhost:9092'
,'properties.group.id' = 'user_log'
,'scan.startup.mode' = 'group-offsets'
,'format' = 'json'
);

drop table if exists hbase_behavior_conf ;
CREATE TEMPORARY TABLE hbase_behavior_conf (
rowkey STRING
,cf ROW(item_id STRING
,category_id STRING
,behavior STRING
,ts TIMESTAMP(3))
) WITH (
'connector' = 'hbase-2.2'
,'zookeeper.quorum' = 'thinkpad:12181'
,'table-name' = 'user_log'
,'lookup.cache.max-rows' = '10000'
,'lookup.cache.ttl' = '10 second'
,'lookup.async' = 'true'
);

---sinkTable
CREATE TABLE kakfa_join_mysql_demo (
user_id STRING
,item_id STRING
,category_id STRING
,behavior STRING
,behavior_map STRING
,ts TIMESTAMP(3)
-- ,primary key (user_id) not enforced
) WITH (
'connector' = 'kafka'
,'topic' = 'user_behavior_1'
,'properties.bootstrap.servers' = 'localhost:9092'
,'properties.group.id' = 'user_log'
,'scan.startup.mode' = 'group-offsets'
,'format' = 'json'
);

INSERT INTO kakfa_join_mysql_demo(user_id, item_id, category_id, behavior, behavior_map, ts)
SELECT a.user_id, a.item_id, a.category_id, a.behavior, concat('map_', c.cf.item_id), a.ts
FROM user_log a
left join hbase_behavior_conf FOR SYSTEM_TIME AS OF a.process_time AS c
ON a.user_id = rowkey
where a.behavior is not null;

测试 hbase 维表Lookup 功能正常，可以正常缓存数据，缓存也会定时失效，透查Hbase

* 注： 随便测试了一下性能，Hbase 维表有2 万多条数据，输入数据的关联字段都是Hbase 表主键，lookup.cache.ttl 为 1分钟，关联的 TPS 轻松到达： 2W

## join 非 rowkey

join 非主键时，hbase 维表启动时一次性读取 hbase 表全部数据，缓存到内存中，hbase source 状态 finish

INSERT INTO kakfa_join_mysql_demo(user_id, item_id, category_id, behavior, behavior_map, ts)
SELECT a.user_id, a.item_id, a.category_id, a.behavior, concat('map_', c.cf.item_id), a.ts
FROM user_log a
left join hbase_behavior_conf c ON a.item_id = cf.item_id
where a.behavior is not null;

* 注： 这种情况在 flink 1.13 版本，不能完成 checkpoint

2021-08-20 09:12:39,313 INFO org.apache.flink.runtime.executiongraph.ExecutionGraph [] - Source: TableSourceScan(table=[[default_catalog, default_database, hbase_behavior_conf, project=[cf]]], fields=[cf]) -> Calc(select=[cf, cf.item_id AS $f2]) (1/1) (55be6048b81e2eef95f25d78b3705a34) switched from RUNNING to FINISHED.
2021-08-20 09:13:30,356 INFO org.apache.flink.runtime.checkpoint.CheckpointCoordinator [] - Failed to trigger checkpoint for job 971bbb75c7334b0c2b9d218005efbf00 since some tasks of job 971bbb75c7334b0c2b9d218005efbf00 has been finished, abort the checkpoint Failure reason: Not all required tasks are currently running.

Hbase 关联只有在关联键是Hbase 表的主键的时候，才能应用 Lookup 功能，非主键一次性加载，维表数据没办法更新，而且不能做 Checkpoint 影响 Flink job 的一致性。

在之前版本，SQL 功能不完善的时候，我们使用 UDF 的方式关联 Hbase，可以在 UDF 里面自己关联缓存、透查Hbase，也比较灵活。（没找到之前的代码，空了自己写一个，可以再水一篇博客）

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