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The "Hbase/Shell" page has been changed by Misty: https://wiki.apache.org/hadoop/Hbase/Shell?action=diff&rev1=13&rev2=14 - This page describes the JRuby IRB-based HBase Shell. It replaces the SQL-like [[Hbase/HbaseShell|HQL]], the Shell found in HBase versions 0.1.x and previous. Some discussion of new shell requirements can be found in the [[Hbase/Shell/Replacement|Shell Replacement]] document. + The HBase Wiki is in the process of being decommissioned. The info that used to be on this page has moved to http://hbase.apache.org/book.html#shell. Please update your bookmarks. - To run the shell, do - - {{{ - $ ${HBASE_HOME}/bin/hbase shell - }}} - You'll be presented with a prompt like the following: - - {{{ - HBase Shell; enter 'help<RETURN>' for list of supported commands. - Version: 0.2.0-dev, r670701, Mon Jun 23 17:26:36 PDT 2008 - hbase(main):001:0> - }}} - Type 'help' followed by a return to get a listing of commands. - - == Commands == - {{{ - hbase(main):001:0> help - HBASE SHELL COMMANDS: - alter Alter column family schema; pass table name and a dictionary - specifying new column family schema. Dictionaries are described - below in the GENERAL NOTES section. Dictionary must include name - of column family to alter. For example, - - To change or add the 'f1' column family in table 't1' from defaults - to instead keep a maximum of 5 cell VERSIONS, do: - hbase> alter 't1', {NAME => 'f1', VERSIONS => 5} - - To delete the 'f1' column family in table 't1', do: - hbase> alter 't1', {NAME => 'f1', METHOD => 'delete'} - - You can also change table-scope attributes like MAX_FILESIZE - MEMSTORE_FLUSHSIZE and READONLY. - - For example, to change the max size of a family to 128MB, do: - hbase> alter 't1', {METHOD => 'table_att', MAX_FILESIZE => '134217728'} - - count Count the number of rows in a table. This operation may take a LONG - time (Run '$HADOOP_HOME/bin/hadoop jar hbase.jar rowcount' to run a - counting mapreduce job). Current count is shown every 1000 rows by - default. Count interval may be optionally specified. Examples: - - hbase> count 't1' - hbase> count 't1', 100000 - - create Create table; pass table name, a dictionary of specifications per - column family, and optionally a dictionary of table configuration. - Dictionaries are described below in the GENERAL NOTES section. - Examples: - - hbase> create 't1', {NAME => 'f1', VERSIONS => 5} - hbase> create 't1', {NAME => 'f1'}, {NAME => 'f2'}, {NAME => 'f3'} - hbase> # The above in shorthand would be the following: - hbase> create 't1', 'f1', 'f2', 'f3' - hbase> create 't1', {NAME => 'f1', VERSIONS => 1, TTL => 2592000, \ - BLOCKCACHE => true} - - describe Describe the named table: e.g. "hbase> describe 't1'" - - delete Put a delete cell value at specified table/row/column and optionally - timestamp coordinates. Deletes must match the deleted cell's - coordinates exactly. When scanning, a delete cell suppresses older - versions. Takes arguments like the 'put' command described below - - deleteall Delete all cells in a given row; pass a table name, row, and optionally - a column and timestamp - - disable Disable the named table: e.g. "hbase> disable 't1'" - - drop Drop the named table. Table must first be disabled. If table has - more than one region, run a major compaction on .META.: - - hbase> major_compact ".META." - - enable Enable the named table - - exists Does the named table exist? e.g. "hbase> exists 't1'" - - exit Type "hbase> exit" to leave the HBase Shell - - get Get row or cell contents; pass table name, row, and optionally - a dictionary of column(s), timestamp and versions. Examples: - - hbase> get 't1', 'r1' - 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', TIMESTAMP => ts1, \ - VERSIONS => 4} - - list List all tables in hbase - - put Put a cell 'value' at specified table/row/column and optionally - timestamp coordinates. To put a cell value into table 't1' at - row 'r1' under column 'c1' marked with the time 'ts1', do: - - hbase> put 't1', 'r1', 'c1', 'value', ts1 - - tools Listing of hbase surgery tools - - scan Scan a table; pass table name and optionally a dictionary of scanner - specifications. Scanner specifications may include one or more of - the following: LIMIT, STARTROW, STOPROW, TIMESTAMP, or COLUMNS. If - no columns are specified, all columns will be scanned. To scan all - members of a column family, leave the qualifier empty as in - 'col_family:'. Examples: - - hbase> scan '.META.' - hbase> scan '.META.', {COLUMNS => 'info:regioninfo'} - hbase> scan 't1', {COLUMNS => ['c1', 'c2'], LIMIT => 10, \ - STARTROW => 'xyz'} - - For experts, there is an additional option -- CACHE_BLOCKS -- which - switches block caching for the scanner on (true) or off (false). By - default it is enabled. Examples: - - hbase> scan 't1', {COLUMNS => ['c1', 'c2'], CACHE_BLOCKS => false} - - 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' - - shutdown Shut down the cluster. - - truncate Disables, drops and recreates the specified table. - - version Output this HBase version - - GENERAL NOTES: - Quote all names in the hbase shell such as table and column names. Don't - forget 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', ...} - - They 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. - - In case you are using binary keys or values and need to enter them into the - shell then use double-quotes to make use of hexadecimal or octal notations, - 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" - - Using the double-quote notation you can directly use the values output by the - shell for example during a "scan" call. - - This HBase shell is the JRuby IRB with the above HBase-specific commands added. - For more on the HBase Shell, see http://wiki.apache.org/hadoop/Hbase/Shell - }}} - === General Notes === - GENERAL NOTES: Quote all names in the hbase shell such as table and column names. Don't forget 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', ...} - - They 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. - - This HBase shell is the JRuby IRB with the above HBase-specific commands added. - - == Anatomy Lesson == - The HBase Shell is a ruby script, ''${HBASE_HOME}/bin/hirb.rb'', that is passed to the JRuby class ''org.jruby.Main'' (See ''${HBASE_HOME}/bin/shell'' and search for org.jruby.Main to see how its done). - - The ''hirb.rb' script defines a set of hbase methods (get, set, scan, etc.), sets some environment variables, imports a few hbase-particular modules -- a results Formatter and a ruby wrapper around the ''HBaseAdmin'' and ''HTable'' java classes that can be found at ''${HBASE_HOME}/bin/HBase.rb'' -- and then starts up a subclass of IRB, named HIRB (IRB is the name of the interactive Ruby interpreter; for an untainted irb experience, type 'irb' on a system that has ruby installed). The subclassing is done to alter slightly some of the usual IRB behaviors. For instance, every command invocation returns a result and the result is printed to the terminal even if the result is nil. The subclass intercepts nil emissions and just suppresses them. '' - - Anything you can do in irb, or at least in its JRuby equivalent, ''jirb'', you should be able to do in HBase Shell. - - == Scripting == - You can pass scripts to the HBase Shell by doing the following: - - {{{ - durruti:~ stack$ ${HBASE_HOME}/bin/hbase shell PATH_TO_SCRIPT - }}} - - Your script can lean on the methods provided by the HBase Shell. - - For more control, you may prefer manipulating HTable and HBaseAdmin methods directly. For example, if you would do your own formatting or you are storing structures that are mangled when manipulated in HBase Shell. In this case, you might pass your scripts directly to JRuby by doing: - - {{{ - durruti:~ stack$ ${HBASE_HOME}/bin/hbase org.jruby.Main PATH_TO_SCRIPT - }}} - - For examples writing straight ruby manhandling hbase client instances, see the scripts on this page: [[Hbase/JRuby]] (Ignore the sections that have you fetching the jruby jar and the prefacing your scripts with the '#!' bang magic). - - == Useful Tricks == - === irbrc === - Create an ''.irbrc'' file for yourself in your home directory. Add HBase Shell customizations. A useful one is command history: - - {{{ - durruti:~ stack$ more .irbrc - require 'irb/ext/save-history' - IRB.conf[:SAVE_HISTORY] = 100 - IRB.conf[:HISTORY_FILE] = "#{ENV['HOME']}/.irb-save-history" - }}} - - === Log date to timestamp === - To convert the date '08/08/16 20:56:29' from an hbase log into a timestamp, do: {{{ - hbase(main):021:0> import java.text.SimpleDateFormat - hbase(main):022:0> import java.text.ParsePosition - hbase(main):023:0> SimpleDateFormat.new("yy/MM/dd HH:mm:ss").parse("08/08/16 20:56:29", ParsePosition.new(0)).getTime() => 1218920189000 - }}} - - To go the other direction, do: {{{ - hbase(main):021:0> import java.util.Date - hbase(main):022:0> Date.new(1218920189000).toString() => "Sat Aug 16 20:56:29 UTC 2008" - }}} - - To output in a format that is exactly like hbase log format is a pain messing with SimpleDateFormat. -
