重磅!解锁Apache Flink读写Apache Hudi新姿势
感谢阿里云 Blink 团队Danny Chan的投稿及完善Flink与Hudi集成工作。
Hudi 和 Fink 在 0.8.0 版本(0.8.0版本将在近期发布,也可直接编译master分支获取hudi-flink-bundle.jar包)做了大量的集成工作[1]。核心的工作包括:
•实现了新的 Flink Streaming Writer•支持 Flink SQL API•支持 batch 和 streaming 的模式 Reader
本文用 Flink SQL Client 来简单的演示通过 Flink SQL API 的方式实现 Hudi 表的读写,包括 batch 模式的读写和 streaming 模式的读。
1. 环境准备
本文使用 Flink Sql Client[2] 作为演示工具,Sql CLI 可以比较方便的执行 SQL 的交互操作。
1.1 下载 Flink jar
Hudi 集成了 Flink 的 1.11 版本。您可以参考 这里[3] 来设置 Flink 环境。hudi-flink-bundle jar 是一个集成了 Flink 相关的 jar 的 uber jar, 目前推荐使用 scala 2.11 来编译。
1.2 设置 Flink 集群
启动一个 standalone 的 Flink 集群。启动之前,建议将 Flink 的集群配置设置如下:
•在 $FLINK_HOME/conf/flink-conf.yaml 中添加配置项 taskmanager.numberOfTaskSlots: 4•在 $FLINK_HOME/conf/workers 中将条目 localhost 设置成 4 行,这里的行数代表了本地启动的 worker 数
启动集群:
# HADOOP_HOME is your hadoop root directory after unpack the binary package.
export HADOOP_CLASSPATH=`$HADOOP_HOME/bin/hadoop classpath`
# Start the flink standalone cluster
./bin/start-cluster.sh
1.3 启动 Flink SQL Client
Hudi 的 bundle jar 应该在 Sql Client 启动的时候加载到 CLASSPATH 中。您可以再路径 hudi-source-dir/packaging/hudi-flink-bundle 下手动编译 jar 包或者从 Apache Official Repository[4] 下载。
启动 SQL CLI:
# HADOOP_HOME is your hadoop root directory after unpack the binary package.
export HADOOP_CLASSPATH=`$HADOOP_HOME/bin/hadoop classpath`
./bin/sql-client.sh embedded -j .../hudi-flink-bundle_2.1?-*.*.*.jar shell
注意:
•推荐使用 hadoop 2.9.x+ 版本,因为一些对象存储(aliyun-oss)从这个版本开始支持•flink-parquet
和 flink-avro
已经被打进 hudi-flink-bundle jar•您也可以直接将 hudi-flink-bundle jar 拷贝到 $FLINK_HOME/lib
目录下•本文的存储选取了对象存储 aliyun-oss,为了方便,您也可以使用本地路径
演示的工作目录结构如下:
/Users/chenyuzhao/workspace/hudi-demo
/- flink-1.11.3
/- hadoop-2.9.2
2. Batch 模式的读写
2.1 插入数据
使用如下 DDL 语句创建 Hudi 表:
Flink SQL> create table t2(
> uuid varchar(20),
> name varchar(10),
> age int,
> ts timestamp(3),
> `partition` varchar(20)
> )
> PARTITIONED BY (`partition`)
> with (
> 'connector' = 'hudi',
> 'path' = 'oss://vvr-daily/hudi/t2'
> );
[INFO] Table has been created.
DDL 里申明了表的 path
,record key 为默认值 uuid
,pre-combine key 为默认值 ts
。
然后通过 VALUES
语句往表中插入数据:
Flink SQL> insert into t2 values
> ('id1','Danny',23,TIMESTAMP '1970-01-01 00:00:01','par1'),
> ('id2','Stephen',33,TIMESTAMP '1970-01-01 00:00:02','par1'),
> ('id3','Julian',53,TIMESTAMP '1970-01-01 00:00:03','par2'),
> ('id4','Fabian',31,TIMESTAMP '1970-01-01 00:00:04','par2'),
> ('id5','Sophia',18,TIMESTAMP '1970-01-01 00:00:05','par3'),
> ('id6','Emma',20,TIMESTAMP '1970-01-01 00:00:06','par3'),
> ('id7','Bob',44,TIMESTAMP '1970-01-01 00:00:07','par4'),
> ('id8','Han',56,TIMESTAMP '1970-01-01 00:00:08','par4');
[INFO] Submitting SQL update statement to the cluster...
[INFO] Table update statement has been successfully submitted to the cluster:
Job ID: 59f2e528d14061f23c552a7ebf9a76bd
这里可以看到 Flink 的作业已经成功提交到集群,可以本地打开 web UI 观察作业的执行情况:
2.2 查询数据
作业执行完成,通过 SELECT
语句查询表结果:
Flink SQL> set execution.result-mode=tableau;
[INFO] Session property has been set.
Flink SQL> select * from t2;
+-----+----------------------+----------------------+-------------+-------------------------+----------------------+
| +/- | uuid | name | age | ts | partition |
+-----+----------------------+----------------------+-------------+-------------------------+----------------------+
| + | id3 | Julian | 53 | 1970-01-01T00:00:03 | par2 |
| + | id4 | Fabian | 31 | 1970-01-01T00:00:04 | par2 |
| + | id7 | Bob | 44 | 1970-01-01T00:00:07 | par4 |
| + | id8 | Han | 56 | 1970-01-01T00:00:08 | par4 |
| + | id1 | Danny | 23 | 1970-01-01T00:00:01 | par1 |
| + | id2 | Stephen | 33 | 1970-01-01T00:00:02 | par1 |
| + | id5 | Sophia | 18 | 1970-01-01T00:00:05 | par3 |
| + | id6 | Emma | 20 | 1970-01-01T00:00:06 | par3 |
+-----+----------------------+----------------------+-------------+-------------------------+----------------------+
Received a total of 8 rows
这里执行语句 set execution.result-mode=tableau;
可以让查询结果直接输出到终端。
通过在 WHERE
子句中添加 partition 路径来裁剪 partition:
Flink SQL> select * from t2 where `partition` = 'par1';
+-----+----------------------+----------------------+-------------+-------------------------+----------------------+
| +/- | uuid | name | age | ts | partition |
+-----+----------------------+----------------------+-------------+-------------------------+----------------------+
| + | id1 | Danny | 23 | 1970-01-01T00:00:01 | par1 |
| + | id2 | Stephen | 33 | 1970-01-01T00:00:02 | par1 |
+-----+----------------------+----------------------+-------------+-------------------------+----------------------+
Received a total of 2 rows
2.3 更新数据
相同的 record key 的数据会自动覆盖,通过 INSERT
相同 key 的数据可以实现更新操作:
Flink SQL> insert into t2 values
> ('id1','Danny',24,TIMESTAMP '1970-01-01 00:00:01','par1'),
> ('id2','Stephen',34,TIMESTAMP '1970-01-01 00:00:02','par1');
[INFO] Submitting SQL update statement to the cluster...
[INFO] Table update statement has been successfully submitted to the cluster:
Job ID: 944de5a1ecbb7eeb4d1e9e748174fe4c
Flink SQL> select * from t2;
+-----+----------------------+----------------------+-------------+-------------------------+----------------------+
| +/- | uuid | name | age | ts | partition |
+-----+----------------------+----------------------+-------------+-------------------------+----------------------+
| + | id1 | Danny | 24 | 1970-01-01T00:00:01 | par1 |
| + | id2 | Stephen | 34 | 1970-01-01T00:00:02 | par1 |
| + | id3 | Julian | 53 | 1970-01-01T00:00:03 | par2 |
| + | id4 | Fabian | 31 | 1970-01-01T00:00:04 | par2 |
| + | id5 | Sophia | 18 | 1970-01-01T00:00:05 | par3 |
| + | id6 | Emma | 20 | 1970-01-01T00:00:06 | par3 |
| + | id7 | Bob | 44 | 1970-01-01T00:00:07 | par4 |
| + | id8 | Han | 56 | 1970-01-01T00:00:08 | par4 |
+-----+----------------------+----------------------+-------------+-------------------------+----------------------+
Received a total of 8 rows
可以看到 uuid
为 id1
和 id2
的数据 age
字段值发生了更新。
再次 insert 新数据观察结果:
Flink SQL> insert into t2 values
> ('id4','Fabian',32,TIMESTAMP '1970-01-01 00:00:04','par2'),
> ('id5','Sophia',19,TIMESTAMP '1970-01-01 00:00:05','par3');
[INFO] Submitting SQL update statement to the cluster...
[INFO] Table update statement has been successfully submitted to the cluster:
Job ID: fdeb7fd9f08808e66d77220f43075720
Flink SQL> select * from t2;
+-----+----------------------+----------------------+-------------+-------------------------+----------------------+
| +/- | uuid | name | age | ts | partition |
+-----+----------------------+----------------------+-------------+-------------------------+----------------------+
| + | id5 | Sophia | 19 | 1970-01-01T00:00:05 | par3 |
| + | id6 | Emma | 20 | 1970-01-01T00:00:06 | par3 |
| + | id3 | Julian | 53 | 1970-01-01T00:00:03 | par2 |
| + | id4 | Fabian | 32 | 1970-01-01T00:00:04 | par2 |
| + | id1 | Danny | 24 | 1970-01-01T00:00:01 | par1 |
| + | id2 | Stephen | 34 | 1970-01-01T00:00:02 | par1 |
| + | id7 | Bob | 44 | 1970-01-01T00:00:07 | par4 |
| + | id8 | Han | 56 | 1970-01-01T00:00:08 | par4 |
+-----+----------------------+----------------------+-------------+-------------------------+----------------------+
Received a total of 8 rows
3. Streaming 读
通过如下语句创建一张新的表并插入如下数据:
Flink SQL> create table t1(
> uuid varchar(20),
> name varchar(10),
> age int,
> ts timestamp(3),
> `partition` varchar(20)
> )
> PARTITIONED BY (`partition`)
> with (
> 'connector' = 'hudi',
> 'path' = 'oss://vvr-daily/hudi/t1',
> 'table.type' = 'MERGE_ON_READ',
> 'read.streaming.enabled' = 'true',
> 'read.streaming.check-interval' = '4'
> );
[INFO] Table has been created.
Flink SQL> insert into t1 values
> ('id1','Danny',23,TIMESTAMP '1970-01-01 00:00:01','par1'),
> ('id2','Stephen',33,TIMESTAMP '1970-01-01 00:00:02','par1'),
> ('id3','Julian',53,TIMESTAMP '1970-01-01 00:00:03','par2'),
> ('id4','Fabian',31,TIMESTAMP '1970-01-01 00:00:04','par2'),
> ('id5','Sophia',18,TIMESTAMP '1970-01-01 00:00:05','par3'),
> ('id6','Emma',20,TIMESTAMP '1970-01-01 00:00:06','par3'),
> ('id7','Bob',44,TIMESTAMP '1970-01-01 00:00:07','par4'),
> ('id8','Han',56,TIMESTAMP '1970-01-01 00:00:08','par4');
[INFO] Submitting SQL update statement to the cluster...
[INFO] Table update statement has been successfully submitted to the cluster:
Job ID: 9e1dcd37fd0f8ca77534c30c7d87be2c
这里将 table option read.streaming.enabled
设置为 true
,表明通过 streaming 的方式读取表数据,opiton read.streaming.check-interval
指定了 source 监控新的 commits 的间隔为 4s,option table.type
设置表类型为 MERGE_ON_READ
,目前只有 MERGE_ON_READ
表支持 streaming 读。
以上操作发生在一个 terminal 中,我们称之为 terminal_1。
从新的 terminal(我们称之为 terminal_2)启动 Sql Client,重新创建 t1
表并查询:
Flink SQL> set execution.result-mode=tableau;
[INFO] Session property has been set.
Flink SQL> create table t1(
> uuid varchar(20),
> name varchar(10),
> age int,
> ts timestamp(3),
> `partition` varchar(20)
> )
> PARTITIONED BY (`partition`)
> with (
> 'connector' = 'hudi',
> 'path' = 'oss://vvr-daily/hudi/t1',
> 'table.type' = 'MERGE_ON_READ',
> 'read.streaming.enabled' = 'true',
> 'read.streaming.check-interval' = '4'
> );
[INFO] Table has been created.
Flink SQL> select * from t1;
2021-03-22 18:36:37,042 INFO org.apache.hadoop.conf.Configuration.deprecation [] - mapred.job.map.memory.mb is deprecated. Instead, use mapreduce.map.memory.mb
+-----+----------------------+----------------------+-------------+-------------------------+----------------------+
| +/- | uuid | name | age | ts | partition |
+-----+----------------------+----------------------+-------------+-------------------------+----------------------+
| + | id2 | Stephen | 33 | 1970-01-01T00:00:02 | par1 |
| + | id1 | Danny | 23 | 1970-01-01T00:00:01 | par1 |
| + | id6 | Emma | 20 | 1970-01-01T00:00:06 | par3 |
| + | id5 | Sophia | 18 | 1970-01-01T00:00:05 | par3 |
| + | id8 | Han | 56 | 1970-01-01T00:00:08 | par4 |
| + | id7 | Bob | 44 | 1970-01-01T00:00:07 | par4 |
| + | id4 | Fabian | 31 | 1970-01-01T00:00:04 | par2 |
| + | id3 | Julian | 53 | 1970-01-01T00:00:03 | par2 |
回到 terminal_1,继续执行 batch mode 的 INSERT
操作:
Flink SQL> insert into t1 values
> ('id1','Danny',27,TIMESTAMP '1970-01-01 00:00:01','par1');
[INFO] Submitting SQL update statement to the cluster...
[INFO] Table update statement has been successfully submitted to the cluster:
Job ID: 2dad24e067b38bc48c3a8f84e793e08b
几秒之后,观察 terminal_2 的输出多了一行:
+-----+----------------------+----------------------+-------------+-------------------------+----------------------+
| +/- | uuid | name | age | ts | partition |
+-----+----------------------+----------------------+-------------+-------------------------+----------------------+
| + | id2 | Stephen | 33 | 1970-01-01T00:00:02 | par1 |
| + | id1 | Danny | 23 | 1970-01-01T00:00:01 | par1 |
| + | id6 | Emma | 20 | 1970-01-01T00:00:06 | par3 |
| + | id5 | Sophia | 18 | 1970-01-01T00:00:05 | par3 |
| + | id8 | Han | 56 | 1970-01-01T00:00:08 | par4 |
| + | id7 | Bob | 44 | 1970-01-01T00:00:07 | par4 |
| + | id4 | Fabian | 31 | 1970-01-01T00:00:04 | par2 |
| + | id3 | Julian | 53 | 1970-01-01T00:00:03 | par2 |
| + | id1 | Danny | 27 | 1970-01-01T00:00:01 | par1 |
再次在 terminal_1 中执行 INSERT
操作:
Flink SQL> insert into t1 values
> ('id4','Fabian',32,TIMESTAMP '1970-01-01 00:00:04','par2'),
> ('id5','Sophia',19,TIMESTAMP '1970-01-01 00:00:05','par3');
[INFO] Submitting SQL update statement to the cluster...
[INFO] Table update statement has been successfully submitted to the cluster:
Job ID: ecafffda3d294a13b0a945feb9acc8a5
观察 terminal_2 的输出变化:
+-----+----------------------+----------------------+-------------+-------------------------+----------------------+
| +/- | uuid | name | age | ts | partition |
+-----+----------------------+----------------------+-------------+-------------------------+----------------------+
| + | id2 | Stephen | 33 | 1970-01-01T00:00:02 | par1 |
| + | id1 | Danny | 23 | 1970-01-01T00:00:01 | par1 |
| + | id6 | Emma | 20 | 1970-01-01T00:00:06 | par3 |
| + | id5 | Sophia | 18 | 1970-01-01T00:00:05 | par3 |
| + | id8 | Han | 56 | 1970-01-01T00:00:08 | par4 |
| + | id7 | Bob | 44 | 1970-01-01T00:00:07 | par4 |
| + | id4 | Fabian | 31 | 1970-01-01T00:00:04 | par2 |
| + | id3 | Julian | 53 | 1970-01-01T00:00:03 | par2 |
| + | id1 | Danny | 27 | 1970-01-01T00:00:01 | par1 |
| + | id5 | Sophia | 19 | 1970-01-01T00:00:05 | par3 |
| + | id4 | Fabian | 32 | 1970-01-01T00:00:04 | par2 |
4. 总结
通过一些简单的演示,我们发现 HUDI Flink 的集成已经相对完善,读写路径均已覆盖,关于详细的配置,可以参考 Flink SQL Config Options[5]。
推荐阅读
阿里云数据湖分析基于Apache Hudi构建下一代Lakehouse
基于Apache Hudi的数据湖帮「宇宙行」节省百万预算!
引用链接
[1]
集成工作: https://issues.apache.org/jira/browse/HUDI-1521[2]
Flink Sql Client: https://ci.apache.org/projects/flink/flink-docs-stable/dev/table/sqlClient.html[3]
这里: https://flink.apache.org/downloads.html[4]
Apache Official Repository: https://repo.maven.apache.org/maven2/org/apache/hudi/hudi-flink-bundle_2.11/[5]
Flink SQL Config Options: https://hudi.apache.org/docs/configurations.html#flink-options