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Posts tagged ‘HBase’
| 传统关系型数据库 | MapReduce | |
|---|---|---|
| 数据大小 | GB | PB |
| 访问 | 交互式和批处理 | 批处理 |
| 更新 | 多次读写 | 一次写入多次读取 |
| 结构 | 静态模式 | 动态模式 |
| 完整性 | 高 | 低 |
| 横向扩展 | 非线性 | 线性 |
HBase Shell, version 0.90.4, r1150278, Sun Jul 24 15:53:29 PDT 2011
Type 'help "COMMAND"', (e.g. 'help "get"' -- the quotes are necessary) for help on a specific command.
Commands are grouped. Type 'help "COMMAND_GROUP"', (e.g. 'help "general"') for help on a command group.
COMMAND GROUPS:
Group name: general
Commands: status, version
Group name: ddl
Commands: alter, create, describe, disable, drop, enable, exists, is_disabled, is_enabled, list
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, major_compact, move, split, unassign, zk_dump
Group name: replication
Commands: add_peer, disable_peer, enable_peer, remove_peer, start_replication, stop_replication
SHELL USAGE:
Quote all names in HBase Shell such as table and column names. Commas delimit
command parameters. Type <RETURN> after entering a command to run it.
Dictionaries of configuration used in the creation and alteration of tables are
Ruby Hashes. They look like this:
{'key1' => 'value1', 'key2' => 'value2', ...}
and are opened and closed with curley-braces. Key/values are delimited by the
'=>' character combination. Usually keys are predefined constants such as
NAME, VERSIONS, COMPRESSION, etc. Constants do not need to be quoted. Type
'Object.constants' to see a (messy) list of all constants in the environment.
If you are using binary keys or values and need to enter them in the shell, use
double-quote'd hexadecimal representation. For example:
hbase> get 't1', "key\x03\x3f\xcd"
hbase> get 't1', "key\003\023\011"
hbase> put 't1', "test\xef\xff", 'f1:', "\x01\x33\x40"
The HBase shell is the (J)Ruby IRB with the above HBase-specific commands added.
For more on the HBase Shell, see http://hbase.apache.org/docs/current/book.html
