HBase shell的基本用法
hbase提供了一个shell的终端给用户交互。使用命令hbase shell进入命令界面。通过执行 help可以看到命令的帮助信息。
以网上的一个学生成绩表的例子来演示hbase的用法。
name | grad | course | |
math | art | ||
Tom | 5 | 97 | 87 |
Jim | 4 | 89 | 80 |
这里grad对于表来说是一个只有它自己的列族,course对于表来说是一个有两个列的列族,这个列族由两个列组成math和art,当然我们可以根据我们的需要在course中建立更多的列族,如computer,physics等相应的列添加入course列族。
(1)建立一个表scores,有两个列族grad和courese
代码如下:
hbase(main):001:0> create ‘scores','grade', ‘course'
可以使用list命令来查看当前HBase里有哪些表。使用describe命令来查看表结构。(记得所有的表明、列名都需要加上引号)
(2)按设计的表结构插入值:
代码如下:
put ‘scores','Tom','grade:','5′ put ‘scores','Tom','course:math','97′ put ‘scores','Tom','course:art','87′ put ‘scores','Jim','grade','4′ put ‘scores','Jim','course:','89′ put ‘scores','Jim','course:','80′
put命令比较简单,只有这一种用法:
hbase> put ‘t1′, ‘r1′, ‘c1′, ‘value', ts1
t1指表名,r1指行键名,c1指列名,value指单元格值。ts1指时间戳,一般都省略掉了。
(3)根据键值查询数据
get ‘scores','Jim' get ‘scores','Jim','grade'
get有用法如下:
hbase> get ‘t1′, ‘r1′ hbase> get ‘t1′, ‘r1′, {TIMERANGE => [ts1, ts2]} hbase> get ‘t1′, ‘r1′, {COLUMN => ‘c1′} hbase> get ‘t1′, ‘r1′, {COLUMN => ['c1', 'c2', 'c3']} hbase> get ‘t1′, ‘r1′, {COLUMN => ‘c1′, TIMESTAMP => ts1} hbase> get ‘t1′, ‘r1′, {COLUMN => ‘c1′, TIMERANGE => [ts1, ts2], VERSIONS => 4} hbase> get ‘t1′, ‘r1′, {COLUMN => ‘c1′, TIMESTAMP => ts1, VERSIONS => 4} hbase> get ‘t1′, ‘r1′, ‘c1′ hbase> get ‘t1′, ‘r1′, ‘c1′, ‘c2′ hbase> get ‘t1′, ‘r1′, ['c1', 'c2']
scan ‘scores'
例句如下:
代码如下:
hbase> scan ‘.META.' hbase> scan ‘.META.', {COLUMNS => ‘info:regioninfo'} hbase> scan ‘t1′, {COLUMNS => ['c1', 'c2'], LIMIT => 10, STARTROW => ‘xyz'} hbase> scan ‘t1′, {COLUMNS => ‘c1′, TIMERANGE => [1303668804, 1303668904]} hbase> scan ‘t1′, {FILTER => “(PrefixFilter (‘row2′) AND (QualifierFilter (>=, ‘binary:xyz'))) AND (TimestampsFilter ( 123, 456))”} hbase> scan ‘t1′, {FILTER => org.apache.hadoop.hbase.filter.ColumnPaginationFilter.new(1, 0)}
a. Using a filterString – more information on this is available in the
Filter Language document attached to the HBASE-4176 JIRA
b. Using the entire package name of the filter.
还有一个CACHE_BLOCKS修饰词,开关scan的缓存的,默认是开启的(CACHE_BLOCKS=>true),可以选择关闭(CACHE_BLOCKS=>false)。
(5)删除指定数据
代码如下:
delete ‘scores','Jim','grade' delete ‘scores','Jim'
hbase> delete ‘t1′, ‘r1′, ‘c1′, ts1
如果需要进行全表删除操作,就使用truncate命令,其实没有直接的全表删除命令,这个命令也是disable,drop,create三个命令组合出来的。
(6)修改表结构
代码如下:
disable ‘scores' alter ‘scores',NAME=>'info' enable ‘scores'
a、改变或添加一个列族:
hbase> alter ‘t1′, NAME => ‘f1′, VERSIONS => 5
代码如下:
hbase> alter ‘t1′, NAME => ‘f1′, METHOD => ‘delete' hbase> alter ‘t1′, ‘delete' => ‘f1′
MEMSTORE_FLUSHSIZE, READONLY,和 DEFERRED_LOG_FLUSH: hbase> alter ‘t1′, METHOD => ‘table_att', MAX_FILESIZE => '134217728′
hbase> alter ‘t1′, METHOD => ‘table_att', ‘coprocessor'=> ‘hdfs:///foo.jar|com.foo.FooRegionObserver|1001|arg1=1,arg2=2′
[coprocessor jar file location] | class name | [priority] | [arguments]
hbase> alter ‘t1′, METHOD => ‘table_att_unset', NAME => ‘MAX_FILESIZE' hbase> alter ‘t1′, METHOD => ‘table_att_unset', NAME => ‘coprocessor$1′
hbase> alter ‘t1′, {NAME => ‘f1′}, {NAME => ‘f2′, METHOD => ‘delete'}
代码如下:
hbase> count ‘t1′ hbase> count ‘t1′, INTERVAL => 100000 hbase> count ‘t1′, CACHE => 1000 hbase> count ‘t1′, INTERVAL => 10, CACHE => 1000
(8)disable 和 enable 操作
很多操作需要先暂停表的可用性,比如上边说的alter操作,删除表也需要这个操作。disable_all和enable_all能够操作更多的表。
(9)表的删除
先停止表的可使用性,然后执行删除命令。
drop ‘t1′
代码如下:
COMMAND GROUPS: Group name: general Commands: status, version Group name: ddl Commands: alter, alter_async, alter_status, create, describe, disable, disable_all, drop, drop_all, enable, enable_all, exists, is_disabled, is_enabled, list, show_filters Group name: dml Commands: count, delete, deleteall, get, get_counter, incr, put, scan, truncate Group name: tools Commands: assign, balance_switch, balancer, close_region, compact, flush, hlog_roll, major_compact, move, split, unassign, zk_dump Group name: replication Commands: add_peer, disable_peer, enable_peer, list_peers, remove_peer, start_replication, stop_replication Group name: security Commands: grant, revoke, user_permission
hbase shell脚本
既然是shell命令,当然也可以把所有的hbase shell命令写入到一个文件内,想linux shell脚本程序那样去顺序的执行所有命令。如同写linux shell,把所有hbase shell命令书写在一个文件内,然后执行如下命令即可:
方便好用。
既然是shell命令,当然也可以把所有的hbase shell命令写入到一个文件内,想linux shell脚本程序那样去顺序的执行所有命令。如同写linux shell,把所有hbase shell命令书写在一个文件内,然后执行如下命令即可:
代码如下:
$ hbase shell test.hbaseshell