Hudi特性
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数据湖处理非结构化数据、日志数据、结构化数据
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支持较快upsert/delete, 可插入索引
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Table Schema
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小文件管理Compaction
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ACID语义保证,多版本保证 并具有回滚功能
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savepoint 用户数据恢复的保存点
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支持多种分析引擎 spark、hive、presto
编译Hudi
git clone https://github.com/apache/hudi.git && cd hudi
mvn clean package -DskipTests
hudi 高度耦合spark
执行spark-shell测试Hudi
bin/spark-shell --packages org.apache.spark:spark-avro_2.11:2.4.5 --conf 'spark.serializer=org.apache.spark.serializer.KryoSerializer' --jars /Users/macwei/IdeaProjects/hudi-master/packaging/hudi-spark-bundle/target/hudi-spark-bundle_2.11-0.6.1-SNAPSHOT.jar
hudi 写入数据
// spark-shell
import org.apache.hudi.QuickstartUtils._
import scala.collection.JavaConversions._
import org.apache.spark.sql.SaveMode._
import org.apache.hudi.DataSourceReadOptions._
import org.apache.hudi.DataSourceWriteOptions._
import org.apache.hudi.config.HoodieWriteConfig._
val tableName = "hudi_trips_cow"
val basePath = "file:///tmp/hudi_trips_cow"
val dataGen = new DataGenerator
// spark-shell
val inserts = convertToStringList(dataGen.generateInserts(10))
val df = spark.read.json(spark.sparkContext.parallelize(inserts, 2))
df.write.format("hudi").
options(getQuickstartWriteConfigs).
option(PRECOMBINE_FIELD_OPT_KEY, "ts").
option(RECORDKEY_FIELD_OPT_KEY, "uuid").
option(PARTITIONPATH_FIELD_OPT_KEY, "partitionpath").
option(TABLE_NAME, tableName).
mode(Overwrite).
save(basePath)
读取hudi数据:
val tripsSnapshotDF = spark.
read.
format("hudi").
load(basePath + "/*/*/*/*")
tripsSnapshotDF.createOrReplaceTempView("hudi_trips_snapshot")
spark.sql("select fare, begin_lon, begin_lat, ts from hudi_trips_snapshot where fare > 20.0").show()
+------------------+-------------------+-------------------+-------------+
| fare| begin_lon| begin_lat| ts|
+------------------+-------------------+-------------------+-------------+
| 64.27696295884016| 0.4923479652912024| 0.5731835407930634|1609771934700|
| 93.56018115236618|0.14285051259466197|0.21624150367601136|1610087553306|
| 33.92216483948643| 0.9694586417848392| 0.1856488085068272|1609982888463|
| 27.79478688582596| 0.6273212202489661|0.11488393157088261|1610187369637|
|34.158284716382845|0.46157858450465483| 0.4726905879569653|1610017361855|
| 43.4923811219014| 0.8779402295427752| 0.6100070562136587|1609795685223|
| 66.62084366450246|0.03844104444445928| 0.0750588760043035|1609923236735|
| 41.06290929046368| 0.8192868687714224| 0.651058505660742|1609838517703|
+------------------+-------------------+-------------------+-------------+
spark.sql("select _hoodie_commit_time, _hoodie_record_key, _hoodie_partition_path, rider, driver, fare from hudi_trips_snapshot").show()
+-------------------+--------------------+----------------------+---------+----------+------------------+
|_hoodie_commit_time| _hoodie_record_key|_hoodie_partition_path| rider| driver| fare|
+-------------------+--------------------+----------------------+---------+----------+------------------+
| 20210110225218|3c7ef0e7-86fb-444...| americas/united_s...|rider-213|driver-213| 64.27696295884016|
| 20210110225218|222db9ca-018b-46e...| americas/united_s...|rider-213|driver-213| 93.56018115236618|
| 20210110225218|3fc72d76-f903-4ca...| americas/united_s...|rider-213|driver-213|19.179139106643607|
| 20210110225218|512b0741-e54d-426...| americas/united_s...|rider-213|driver-213| 33.92216483948643|
| 20210110225218|ace81918-0e79-41a...| americas/united_s...|rider-213|driver-213| 27.79478688582596|
| 20210110225218|c76f82a1-d964-4db...| americas/brazil/s...|rider-213|driver-213|34.158284716382845|
| 20210110225218|73145bfc-bcb2-424...| americas/brazil/s...|rider-213|driver-213| 43.4923811219014|
| 20210110225218|9e0b1d58-a1c4-47f...| americas/brazil/s...|rider-213|driver-213| 66.62084366450246|
| 20210110225218|b8fccca1-9c28-444...| asia/india/chennai|rider-213|driver-213|17.851135255091155|
| 20210110225218|6144be56-cef9-43c...| asia/india/chennai|rider-213|driver-213| 41.06290929046368|
+-------------------+--------------------+----------------------+---------+----------+------------------+
对比
数据导入至hadoop方案: maxwell、canal、flume、sqoop
hudi是通用方案
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hudi 支持presto、spark sql下游查询
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hudi存储依赖hdfs
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hudi可以当作数据源或数据库,支持PB级别
概念
Timeline: 时间戳
state：即时状态
原子写入操作
compaction： 后台协调hudi中差异数据
rollback： 回滚
savepoint： 数据还原
任何操作都有以下状态:
- Requested 已安排操作行为,但是没有开始
- Inflight 正在执行当前操作
- Completed 已完成操作
hudi提供两种表类型:
- CopyOnWrite 适用全量数据,列式存储,写入过程执行同步合并重写文件
- MergeOnRead 增量数据,基于列式(parquet)和行式(avro)存储,更新记录到增量文件(日志文件),压缩同步和异步生成新版本文件,延迟更低
hudi查询类型:
- 快照查询 查询最新快照表数据,如果是MergeOnRead表,动态合并最新版本基本数据和增量数据用于显示查询;如果是CopyOnWrite,直接查询Parquet表,同时提供upsert、delete操作
- 增量查询 只能看到写入表的新数据
- 优化读查询 给定时间段的一个查询
资料参考
- Docker Demo: https://hudi.apache.org/docs/docker_demo.html Hudi 官方建议代码测试可在Docker进行, 如果在Docker运行有问题也可以进行Remote Debugger
- Hudi 目前代码写的很多实现其实有点不太好, 如果有想贡献提交PR的可参考: 如何进行开源贡献