显示表的定义语句
show create table table_name
显示表的分区
show partitions table_name
将parquet压缩格式转换成text file格式示例
create table table_name_textfile( --创建一个空表
filedA string
filedB string
filedC string
)
partitioned by (filedD string);
set mapreduce.map.memory.mb=4096;
set mapreduce.reduce.memory.mb=8192;
set mapreduce.map.java.opts=-Djava.net.preferIPv4Stack=true -Xmx3072m;
set mapreduce.reduce.java.opts=-Djava.net.preferIPv4Stack=true -Xmx7168m;
set hive.exec.reducers.max=40960;
set hive.exec.dynamic.partition=true;
set hive.exec.dynamic.partition.mode=nonstrict;
set hive.exec.max.dynamic.partitions=100000;
set hive.exec.max.dynamic.partitions.pernode=10000;
insert overwrite table table_name_textfile_partition(filedD) --将table_name_partition数据插入table_name_textfile
select
a.filedA
a.filedB
a.filedC
a.filedD
from(
select * from table_name_parquet
) a;
---------占坑----------------------hive数据倾斜优化
