HBase从入门到精通6：HBase Shell的使用

HBase提供了一个命令行工具hbase shell以供用户使用。本节来介绍一下HBase Shell中常用的命令。

1.进入hbase shell环境

启动Hadoop

[root@localhost ~]# start-all.sh

启动ZooKeeper

[root@localhost ~]# zkServer.sh start

启动HBase

[root@localhost ~]# start-hbase.sh

进入hbase shell环境

[root@localhost ~]# hbase shell
HBase Shell
Use "help" to get list of supported commands.
Use "exit" to quit this interactive shell.
Version 2.0.1, r987f7b6d37c2fcacc942cc66e5c5122aba8fdfbe, Wed Jun 13 12:03:55 PDT 2018
Took 0.0016 seconds
hbase(main):001:0>

2.简单创建表

hbase(main):001:0> create 'tblStudent','Info','Grade'
Created table tblStudent
Took 1.3997 seconds
=> Hbase::Table - tblStudent

3.高级创建表

hbase(main):001:0> create 'tblStudent',{NAME=>'Info',VERSIONS=>'3',COMPRESSION=>'SNAPPY'},
{NAME=>'Grade',VERSIONS=>'2',COMPRESSION=>'LZO'}

4.列出已有的表

hbase(main):002:0> list
TABLE
tblStudent
1 row(s)
Took 0.0192 seconds
=> ["tblStudent"]

5.查看表结构

hbase(main):003:0> describe 'tblStudent'
Table tblStudent is ENABLED
tblStudent
COLUMN FAMILIES DESCRIPTION
{NAME => 'Grade',
VERSIONS => '1',
EVICT_BLOCKS_ON_CLOSE => 'false',
NEW_VERSION_BEHAVIOR => 'false',
KEEP_DELETED_CELLS => 'FALSE',
CACHE_DATA_ON_WRITE => 'false',
DATA_BLOCK_ENCODING => 'NONE',
TTL => 'FOREVER',
MIN_VERSIONS => '0',
REPLICATION_SCOPE => '0',
BLOOMFILTER => 'ROW',
CACHE_INDEX_ON_WRITE => 'false',
IN_MEMORY => 'false',
CACHE_BLOOMS_ON_WRITE => 'false',
PREFETCH_BLOCKS_ON_OPEN => 'false',
COMPRESSION => 'NONE',
BLOCKCACHE => 'true',
BLOCKSIZE => '65536'}
{NAME => 'Info',
VERSIONS => '1',
EVICT_BLOCKS_ON_CLOSE => 'false',
NEW_VERSION_BEHAVIOR => 'false',
KEEP_DELETED_CELLS => 'FALSE',
CACHE_DATA_ON_WRITE => 'false',
DATA_BLOCK_ENCODING => 'NONE',
TTL => 'FOREVER',
MIN_VERSIONS =>'0',
REPLICATION_SCOPE => '0',
BLOOMFILTER => 'ROW',
CACHE_INDEX_ON_WRITE => 'false',
IN_MEMORY => 'false',
CACHE_BLOOMS_ON_WRITE => 'false',
PREFETCH_BLOCKS_ON_OPEN => 'false',
COMPRESSION => 'NONE',
BLOCKCACHE => 'true',
BLOCKSIZE => '65536'}
2 row(s)
Took 0.1060 seconds

关于HBase表结构的几点说明：

1. NAME：指定列族的名字
2. VERSIONS：指定可以保存的值的版本个数
3. EVICT_BLOCKS_ON_CLOSE：
4. NEW_VERSION_BEHAVIOR：
5. KEEP_DELETED_CELLS：
6. CACHE_DATA_ON_WRITE：
7. DATA_BLOCK_ENCODING：设置数据块编码方式
8. TTL：默认是 2147483647 即:Integer.MAX_VALUE 值大概是68年。这个参数是说明该列族数据的存活时间，单位是s。这个参数可以根据具体的需求对数据设定存活时间，超过存过时间的数据将在表中不在显示，待下次major compact的时候再彻底删除数据。注意的是TTL设定之后 MIN_VERSIONS=>’0’ 这样设置之后，TTL时间戳过期后，将全部彻底删除该family下所有的数据；如果MIN_VERSIONS 不等于0那将保留最新的MIN_VERSIONS个版本的数据，其它的全部删除，比如MIN_VERSIONS=>’1’ 届时将保留一个最新版本的数据，其它版本的数据将不再保存。
9. MIN_VERSIONS：在compact操作执行之后，至少要保留的版本数
10. REPLICATION_SCOPE：配置HBase集群replication时需要将该参数设置为1.
11. BLOOMFILTER：
12. CACHE_INDEX_ON_WRITE：
13. IN_MEMORY：设置激进缓存，优先考虑将该列族放入块缓存中，默认值为false， 针对随机读操作相对较多的列族可以设置该属性为true
14. CACHE_BLOOMS_ON_WRITE：
15. PREFETCH_BLOCKS_ON_OPEN：
16. COMPRESSION：设置压缩算法，默认为NONE。使用压缩可以减少存储，但是会增减计算量。常用的压缩算法如下所示：

image

17. BLOCKCACHE：设置数据块是否缓存，默认为true
18. BLOCKSIZE：设置HFile数据块大小，默认64kb

6.修改表结构

hbase(main):004:0> disable 'tblStudent'
Took 0.5471 seconds
hbase(main):005:0> alter 'tblStudent',{NAME=>'Info',VERSIONS=>'2'}
Updating all regions with the new schema...
All regions updated.
Done.
Took 1.2771 seconds
hbase(main):006:0> enable 'tblStudent'
Took 0.7709 seconds

7.插入记录

hbase(main):007:0> put 'tblStudent','stu001','Info:name','Tom'
Took 0.0697 seconds
hbase(main):008:0> put 'tblStudent','stu001','Info:age','22'
Took 0.0050 seconds
hbase(main):009:0> put 'tblStudent','stu002','Info:name','Jack'
Took 0.0078 seconds
hbase(main):010:0> put 'tblStudent','stu002','Info:age','25'
Took 0.0050 seconds

8.查看单条记录

hbase(main):011:0> get 'tblStudent','stu001'
COLUMN CELL
Info:age timestamp=1532361034202, value=22
Info:name timestamp=1532360807963, value=Tom
1 row(s)
Took 0.0359 seconds

9.查看所有记录

hbase(main):012:0> scan 'tblStudent'
ROW COLUMN+CELL
stu001 column=Info:age, timestamp=1532361034202, value=22
stu001 column=Info:name, timestamp=1532361309771, value=Tom
stu002 column=Info:age, timestamp=1532361111248, value=25
stu002 column=Info:name, timestamp=1532361052962, value=Jack
2 row(s)
Took 0.0112 seconds

10.统计记录数

hbase(main):013:0> count 'tblStudent'
2 row(s)
Took 0.0388 seconds
=> 2

11.查看某个表某个列的所有数据

hbase(main):014:0> scan 'tblStudent',{COLUMNS=>'Info:name'}
ROW COLUMN+CELL
stu001 column=Info:name, timestamp=1532361309771, value=Tom
stu002 column=Info:name, timestamp=1532361052962, value=Jack
2 row(s)
Took 0.0093 seconds

12.更新记录（重写一遍）

hbase(main):015:0> put 'tblStudent','stu001','Info:name','Tommy'
Took 0.0063 seconds
hbase(main):016:0> scan 'tblStudent',{COLUMNS=>'Info:name'}
ROW COLUMN+CELL
stu001 column=Info:name, timestamp=1532361423526, value=Tommy
stu002 column=Info:name, timestamp=1532361052962, value=Jack
2 row(s)
Took 0.0064 seconds

13.删除某条记录的某一列

hbase(main):017:0> delete 'tblStudent','stu002','Info:name'
Took 0.0078 seconds
hbase(main):018:0> scan 'tblStudent',{COLUMNS=>'Info:name'}
ROW COLUMN+CELL
stu001 column=Info:name, timestamp=1532361423526, value=Tommy
1 row(s)
Took 0.0078 seconds

14.清空表中所有数据

hbase(main):019:0> truncate 'tblStudent'
Truncating 'tblStudent' table (it may take a while):

Disabling table...
Truncating table...
Took 1.2209 seconds
hbase(main):020:0> scan 'tblStudent'
ROW COLUMN+CELL
0 row(s)
Took 0.1419 seconds

15.禁用单个表

hbase(main):017:0> disable 'tblStudent'
Took 0.8602 seconds
hbase(main):040:0> scan 'tblStudent'
ROW COLUMN+CELL

ERROR: Table tblStudent is disabled!

16.激活单个表

hbase(main):018:0> enable 'tblStudent'
Took 0.0098 seconds
hbase(main):042:0> scan 'tblStudent'
ROW COLUMN+CELL
0 row(s)
Took 0.0044 seconds

17.禁用多个表

支持正则表达式：

hbase(main):026:0> list
TABLE
tblStudent
tblStudent1
tblStudent2
tblStudent3
4 row(s)
Took 0.0168 seconds
=> ["tblStudent", "tblStudent1", "tblStudent2", "tblStudent3"]
hbase(main):030:0> disable_all 'tblStudent[1-9]'
tblStudent1
tblStudent2
tblStudent3

Disable the above 3 tables (y/n)?
y
3 tables successfully disabled
Took 6.1949 seconds

18.激活多个表

支持正则表达式：

hbase(main):027:0> enable_all 'tblStudent[1-9]'
tblStudent1
tblStudent2
tblStudent3

Enable the above 3 tables (y/n)?
y
3 tables successfully enabled
Took 3.8096 seconds

19.删除单个表

hbase(main):031:0> disable 'tblStudent'
Took 0.0069 seconds
hbase(main):032:0> drop 'tblStudent'
Took 0.2532 seconds
hbase(main):033:0> list
TABLE
tblStudent1
tblStudent2

tblStudent3
3 row(s)
Took 0.0068 seconds
=> ["tblStudent1", "tblStudent2", "tblStudent3"]

20.删除多个表

支持正则表达式：

hbase(main):034:0> disable_all 'tblStudent[1-9]'
tblStudent1
tblStudent2
tblStudent3

Disable the above 3 tables (y/n)?
y
3 tables successfully disabled
Took 1.8435 seconds
hbase(main):035:0> drop_all 'tblStudent[1-9]'
tblStudent1
tblStudent2
tblStudent3

Drop the above 3 tables (y/n)?
y
3 tables successfully dropped
Took 3.0995 seconds
hbase(main):036:0> list
TABLE
0 row(s)
Took 0.0078 seconds
=> []

21.退出hbase shell环境

hbase(main):040:0> quit
[root@master ~]#