spark读写clickhouse

官网文档：https://clickhouse.tech/docs/zh/

spark读取clickhouse数据

一：这种jdbc的连接加载的是全量表数据

val prop = new java.util.Properties
prop.setProperty("user", "default")
prop.setProperty("password", "123456")
prop.setProperty("driver", "ru.yandex.clickhouse.ClickHouseDriver")

val readDataDf = sparkSession
  .read
  .jdbc("jdbc:clickhouse://hadoop102:8123",
    "table_op",
    prop)
  .where("LocationTime>='2021-09-21 09:00:00' AND LocationTime<='2021-09-21 18:00:00'")

二：这种是添加过滤条件加载部分数据（推荐这种，因为如果你的表很大的话spark任务driver启不来）
//将过滤查询提前存到临时表

val tablename = s"(select * from table_op where LocationTime between '$start_time' and '$end_time') temp"

val readDataDf = session.read
  .format("jdbc")
  .option("url", "jdbc:clickhouse://hadoop05:8123")
  .option("fetchsize", "500000")
  .option("driver", "ru.yandex.clickhouse.ClickHouseDriver")
  .option("user", "default")
  .option("password", "123456")
  .option("dbtable", tablename)
  .load()

spark写入clickhouse

val prop = new java.util.Properties
prop.setProperty("user", CommonConfig.CLICK_USER)
prop.setProperty("password", CommonConfig.CLICK_PASSWORD)
prop.setProperty("driver", CommonConfig.CLICK_DRIVER)

resultDataDf
  .write
  .mode(SaveMode.Append)
  .option("batchsize", "500000")
  .option("isolationLevel", "NONE")
  .option("numPartitions", "1")
  .jdbc("jdbc:clickhouse://hadoop102:8123",    //CommonConfig.CLICK_URL
    "table_op_2020", prop)

clickhouse建表

启动clickhouse客户端

clickhouse-client --port 9020 -h hadoop05 -d default -m -u default --password 123456

建表（本地表，分布式表）

一次性在集群每个机器上建立本地表(因为加了on cluster,所以只需在任意一台机器上执行一次建表，集群中每台都会生成本地表；如果不加on cluster,则需要去每台机器都执行一遍建表语句生成本地表)
CREATE TABLE `table_2021` ON CLUSTER fangteCluster (
        `Id` String,
        `Udid` String,
        `LocationTime` String,
        `Gcode` String,
        `IP` String,
        `IMEI` String,
        `IDFA` String,
        `UserId` String,
        `Year` UInt16,
        `Month` UInt8,
        `Day` UInt8
)ENGINE = MergeTree()
PARTITION BY (Year,Month,Day)
ORDER BY (Gcode,Udid) 
SETTINGS index_granularity=8192, enable_mixed_granularity_parts=1;

默认情况下主键跟排序键（由 ORDER BY 子句指定）相同。
因此，大部分情况下不需要再专门指定一个 PRIMARY KEY 子句	
enable_mixed_granularity_parts=1 启用以字节为单位的索引粒度，有助于提升大表的查询性能

一次性在集群所有机器上建立分布式表
CREATE TABLE table_op_2021 ON CLUSTER mycluster AS table_2021 ENGINE = Distributed(mycluster, default, table_2021, rand());
只在一台机器上建分布式表
CREATE TABLE table_op_2021 AS table_2021 ENGINE = Distributed(mycluster, default, table_2021, rand());