Guide Lines

CoreServlets Hbase Installation and Shellf

Quote all names

– Table and column names

– Single quotes for text

• hbase> get 't1', 'myRowId'

– Double quotes for binary

• Use hexadecimal representation of that binary value

• hbase> get 't1', "key\x03\x3f\xcd"

Uses ruby hashes to specify parameters

– {'key1' => 'value1', 'key2' => 'value2', …}

– Example:

Hbase Definitive Guide

Quote names

Commands that require a table or column name expect the name to be quoted in

either single or double quotes.

Quote values

The shell supports the output and input of binary values using a hexadecimal—or

octal—representation. You must use double quotes or the shell will interpret them

as literals.

hbase> get 't1', "key\x00\x6c\x65\x6f\x6e"

hbase> get 't1', "key\000\154\141\165\162\141"

hbase> put 't1', "test\xef\xff", 'f1:', "\x01\x33\x70"

Note the mixture of quotes: you need to make sure you use the correct ones, or

the result might not be what you had expected. Text in single quotes is treated as

a literal, whereas double-quoted text is interpolated, that is, it transforms the octal,

or hexadecimal, values into bytes.

Comma delimiters for parameters

Separate command parameters using commas. For example:

hbase(main):001:0> get 'testtable', 'row-1',

'colfam1:qual1'

Ruby hashes for properties

For some commands, you need to hand in a map with key/value properties. This

is done using Ruby hashes:

{'key1' => 'value1', 'key2' => 'value2', ...}

The keys/values are wrapped in curly braces, and in turn are separated by "=>".

Usually keys are predefined constants such as NAME, VERSIONS, or COMPRESSION, and

do not need to be quoted. For example:

hbase(main):001:0> create 'testtable', {NAME =>

'colfam1', VERSIONS => 1, \

TTL => 2592000, BLOCKCACHE => true}

For any command, you can get detailed help by typing in help '<command>'. Here’s an

example:

hbase(main):001:0> help 'status'

Show cluster status. Can be 'summary', 'simple', or 'detailed'. The

default is 'summary'. Examples:

hbase> status

hbase> status 'simple'

hbase> status 'summary'

hbase> status 'detailed'

The majority of commands have a direct match with a method provided by either the

client or administrative API. Next is a brief overview of each command and the matching API functionality.