1. 引入

Apache Hudi支持多种分区方式数据集，如多级分区、单分区、时间日期分区、无分区数据集等，用户可根据实际需求选择合适的分区方式，下面来详细了解Hudi如何配置何种类型分区。

2. 分区处理

为说明Hudi对不同分区类型的处理，假定写入Hudi的Schema如下

{
  "type" : "record",
  "name" : "HudiSchemaDemo",
  "namespace" : "hoodie.HudiSchemaDemo",
  "fields" : [ {
    "name" : "age",
    "type" : [ "long", "null" ]
  }, {
    "name" : "location",
    "type" : [ "string", "null" ]
  }, {
    "name" : "name",
    "type" : [ "string", "null" ]
  }, {
    "name" : "sex",
    "type" : [ "string", "null" ]
  }, {
    "name" : "ts",
    "type" : [ "long", "null" ]
  }, {
    "name" : "date",
    "type" : [ "string", "null" ]
  } ]
}

其中一条具体数据如下

{
  "name": "zhangsan", 
  "ts": 1574297893837, 
  "age": 16, 
  "location": "beijing", 
  "sex":"male", 
  "date":"2020/08/16"
}

2.1 单分区

单分区表示使用一个字段表示作为分区字段的场景，可具体分为非日期格式字段（如location）和日期格式字段（如date）

2.1.1 非日期格式字段分区

如使用上述location字段作为分区字段，在写入Hudi并同步至Hive时配置如下

df.write().format("org.apache.hudi").
                options(getQuickstartWriteConfigs()).
                option(DataSourceWriteOptions.TABLE_TYPE_OPT_KEY(), "COPY_ON_WRITE").
                option(DataSourceWriteOptions.PRECOMBINE_FIELD_OPT_KEY(), "ts").
                option(DataSourceWriteOptions.RECORDKEY_FIELD_OPT_KEY(), "name").
                option(DataSourceWriteOptions.PARTITIONPATH_FIELD_OPT_KEY(), partitionFields).
                option(DataSourceWriteOptions.KEYGENERATOR_CLASS_OPT_KEY(), keyGenerator).
                option(TABLE_NAME, tableName).
                option("hoodie.datasource.hive_sync.enable", true).
                option("hoodie.datasource.hive_sync.table", tableName).
                option("hoodie.datasource.hive_sync.username", "root").
                option("hoodie.datasource.hive_sync.password", "123456").
                option("hoodie.datasource.hive_sync.jdbcurl", "jdbc:hive2://localhost:10000").
                option("hoodie.datasource.hive_sync.partition_fields", hivePartitionFields).
                option("hoodie.datasource.write.table.type", "COPY_ON_WRITE").
                option("hoodie.embed.timeline.server", false).
                option("hoodie.datasource.hive_sync.partition_extractor_class", hivePartitionExtractorClass).
                mode(saveMode).
                save(basePath);

值得注意如下几个配置项

• DataSourceWriteOptions.PARTITIONPATH_FIELD_OPT_KEY()配置为location；
• hoodie.datasource.hive_sync.partition_fields配置为location，与写入Hudi的分区字段相同；
• DataSourceWriteOptions.KEYGENERATOR_CLASS_OPT_KEY()配置为org.apache.hudi.keygen.SimpleKeyGenerator，或者不配置该选项，默认为org.apache.hudi.keygen.SimpleKeyGenerator；
• hoodie.datasource.hive_sync.partition_extractor_class配置为org.apache.hudi.hive.MultiPartKeysValueExtractor；

Hudi同步到Hive创建的表如下

CREATE EXTERNAL TABLE `notdateformatsinglepartitiondemo`(
  `_hoodie_commit_time` string,
  `_hoodie_commit_seqno` string,
  `_hoodie_record_key` string,
  `_hoodie_partition_path` string,
  `_hoodie_file_name` string,
  `age` bigint,
  `date` string,
  `name` string,
  `sex` string,
  `ts` bigint)
PARTITIONED BY (
  `location` string)
ROW FORMAT SERDE
  'org.apache.hadoop.hive.ql.io.parquet.serde.ParquetHiveSerDe'
STORED AS INPUTFORMAT
  'org.apache.hudi.hadoop.HoodieParquetInputFormat'
OUTPUTFORMAT
  'org.apache.hadoop.hive.ql.io.parquet.MapredParquetOutputFormat'
LOCATION
  'file:/tmp/hudi-partitions/notDateFormatSinglePartitionDemo'
TBLPROPERTIES (
  'last_commit_time_sync'='20200816154250',
  'transient_lastDdlTime'='1597563780')

查询表notdateformatsinglepartitiondemo

tips: 查询时请先将hudi-hive-sync-bundle-xxx.jar包放入$HIVE_HOME/lib下

2.1.2 日期格式分区

如使用上述date字段作为分区字段，核心配置项如下

• DataSourceWriteOptions.PARTITIONPATH_FIELD_OPT_KEY()配置为date；
• hoodie.datasource.hive_sync.partition_fields配置为date，与写入Hudi的分区字段相同；
• DataSourceWriteOptions.KEYGENERATOR_CLASS_OPT_KEY()配置为org.apache.hudi.keygen.SimpleKeyGenerator，或者不配置该选项，默认为org.apache.hudi.keygen.SimpleKeyGenerator；
• hoodie.datasource.hive_sync.partition_extractor_class配置为org.apache.hudi.hive.SlashEncodedDayPartitionValueExtractor；

Hudi同步到Hive创建的表如下

CREATE EXTERNAL TABLE `dateformatsinglepartitiondemo`(
  `_hoodie_commit_time` string,
  `_hoodie_commit_seqno` string,
  `_hoodie_record_key` string,
  `_hoodie_partition_path` string,
  `_hoodie_file_name` string,
  `age` bigint,
  `location` string,
  `name` string,
  `sex` string,
  `ts` bigint)
PARTITIONED BY (
  `date` string)
ROW FORMAT SERDE
  'org.apache.hadoop.hive.ql.io.parquet.serde.ParquetHiveSerDe'
STORED AS INPUTFORMAT
  'org.apache.hudi.hadoop.HoodieParquetInputFormat'
OUTPUTFORMAT
  'org.apache.hadoop.hive.ql.io.parquet.MapredParquetOutputFormat'
LOCATION
  'file:/tmp/hudi-partitions/dateFormatSinglePartitionDemo'
TBLPROPERTIES (
  'last_commit_time_sync'='20200816155107',
  'transient_lastDdlTime'='1597564276')

查询表dateformatsinglepartitiondemo

2.2 多分区

多分区表示使用多个字段表示作为分区字段的场景，如上述使用location字段和sex字段，核心配置项如下

• DataSourceWriteOptions.PARTITIONPATH_FIELD_OPT_KEY()配置为location,sex；
• hoodie.datasource.hive_sync.partition_fields配置为location,sex，与写入Hudi的分区字段相同；
• DataSourceWriteOptions.KEYGENERATOR_CLASS_OPT_KEY()配置为org.apache.hudi.keygen.ComplexKeyGenerator；
• hoodie.datasource.hive_sync.partition_extractor_class配置为org.apache.hudi.hive.MultiPartKeysValueExtractor；

Hudi同步到Hive创建的表如下

CREATE EXTERNAL TABLE `multipartitiondemo`(
  `_hoodie_commit_time` string,
  `_hoodie_commit_seqno` string,
  `_hoodie_record_key` string,
  `_hoodie_partition_path` string,
  `_hoodie_file_name` string,
  `age` bigint,
  `date` string,
  `name` string,
  `ts` bigint)
PARTITIONED BY (
  `location` string,
  `sex` string)
ROW FORMAT SERDE
  'org.apache.hadoop.hive.ql.io.parquet.serde.ParquetHiveSerDe'
STORED AS INPUTFORMAT
  'org.apache.hudi.hadoop.HoodieParquetInputFormat'
OUTPUTFORMAT
  'org.apache.hadoop.hive.ql.io.parquet.MapredParquetOutputFormat'
LOCATION
  'file:/tmp/hudi-partitions/multiPartitionDemo'
TBLPROPERTIES (
  'last_commit_time_sync'='20200816160557',
  'transient_lastDdlTime'='1597565166')

查询表multipartitiondemo

2.3 无分区

无分区场景是指无分区字段，写入Hudi的数据集无分区。核心配置如下

• DataSourceWriteOptions.PARTITIONPATH_FIELD_OPT_KEY()配置为空字符串；
• hoodie.datasource.hive_sync.partition_fields配置为空字符串，与写入Hudi的分区字段相同；
• DataSourceWriteOptions.KEYGENERATOR_CLASS_OPT_KEY()配置为org.apache.hudi.keygen.NonpartitionedKeyGenerator；
• hoodie.datasource.hive_sync.partition_extractor_class配置为org.apache.hudi.hive.NonPartitionedExtractor；

Hudi同步到Hive创建的表如下

CREATE EXTERNAL TABLE `nonpartitiondemo`(
  `_hoodie_commit_time` string,
  `_hoodie_commit_seqno` string,
  `_hoodie_record_key` string,
  `_hoodie_partition_path` string,
  `_hoodie_file_name` string,
  `age` bigint,
  `date` string,
  `location` string,
  `name` string,
  `sex` string,
  `ts` bigint)
ROW FORMAT SERDE
  'org.apache.hadoop.hive.ql.io.parquet.serde.ParquetHiveSerDe'
STORED AS INPUTFORMAT
  'org.apache.hudi.hadoop.HoodieParquetInputFormat'
OUTPUTFORMAT
  'org.apache.hadoop.hive.ql.io.parquet.MapredParquetOutputFormat'
LOCATION
  'file:/tmp/hudi-partitions/nonPartitionDemo'
TBLPROPERTIES (
  'last_commit_time_sync'='20200816161558',
  'transient_lastDdlTime'='1597565767')

查询表nonpartitiondemo

2.4 Hive风格分区

除了上述几种常见的分区方式，还有一种Hive风格分区格式，如location=beijing/sex=male格式，以location,sex作为分区字段，核心配置如下

• DataSourceWriteOptions.PARTITIONPATH_FIELD_OPT_KEY()配置为location,sex；
• hoodie.datasource.hive_sync.partition_fields配置为location,sex，与写入Hudi的分区字段相同；
• DataSourceWriteOptions.KEYGENERATOR_CLASS_OPT_KEY()配置为org.apache.hudi.keygen.ComplexKeyGenerator；
• hoodie.datasource.hive_sync.partition_extractor_class配置为org.apache.hudi.hive.SlashEncodedDayPartitionValueExtractor；
• DataSourceWriteOptions.HIVE_STYLE_PARTITIONING_OPT_KEY()配置为true；

生成的Hudi数据集目录结构会为如下格式

/location=beijing/sex=male

Hudi同步到Hive创建的表如下

CREATE EXTERNAL TABLE `hivestylepartitiondemo`(
  `_hoodie_commit_time` string,
  `_hoodie_commit_seqno` string,
  `_hoodie_record_key` string,
  `_hoodie_partition_path` string,
  `_hoodie_file_name` string,
  `age` bigint,
  `date` string,
  `name` string,
  `ts` bigint)
PARTITIONED BY (
  `location` string,
  `sex` string)
ROW FORMAT SERDE
  'org.apache.hadoop.hive.ql.io.parquet.serde.ParquetHiveSerDe'
STORED AS INPUTFORMAT
  'org.apache.hudi.hadoop.HoodieParquetInputFormat'
OUTPUTFORMAT
  'org.apache.hadoop.hive.ql.io.parquet.MapredParquetOutputFormat'
LOCATION
  'file:/tmp/hudi-partitions/hiveStylePartitionDemo'
TBLPROPERTIES (
  'last_commit_time_sync'='20200816172710',
  'transient_lastDdlTime'='1597570039')

查询表hivestylepartitiondemo

3. 总结

本篇文章介绍了Hudi如何处理不同分区场景，上述配置的分区类配置可以满足绝大多数场景，当然Hudi非常灵活，还支持自定义分区解析器，具体可查看KeyGenerator和PartitionValueExtractor类，其中所有写入Hudi的分区字段生成器都是KeyGenerator的子类，所有同步至Hive的分区值解析器都是PartitionValueExtractor的子类。