hive 存储格式

hive有textFile,SequenceFile,RCFile三种文件格式。

textfile为默认格式，建表时不指定默认为这个格式，导入数据时会直接把数据文件拷贝到hdfs上不进行处理。

SequenceFile,RCFile格式的表不能直接从本地文件导入数据，数据要先导入到textfile格式的表中，

然后再从textfile表中用insert导入到SequenceFile,RCFile表中。

create table zone0000tf(ra int, dec int, mag int) row format delimited fields terminated by '|';
create table zone0000rc(ra int, dec int, mag int) row format delimited fields
terminated by '|' stored as rcfile;

load data local inpath '/home/cq/usnoa/zone0000.asc ' into table zone0000tf;
insert overwrite table zone0000rc select * from zone0000tf;(begin a job)

File Format

	TextFile	SequenceFIle	RCFFile
Data type	Text Only	Text/Binary	Text/Binary
Internal Storage Order	Row-based	Row-based	Column-based
Compression	File Based	Block Based	Block Based
Splitable	YES	YES	YES
Splitable After Compression	No	YES	YES