- describe ‘tablename’ :
Displays the metadata of particular table
Example :describe 'employee' {NAME => 'address', BLOOMFILTER => 'ROW', VERSIONS => '5', IN_MEMORY => 'false', KEEP_DELETED_CELLS => 'FALSE', DATA_BLOCK_ENCODING => 'NONE', TTL => 'FOREVER', COMPRESSION => 'GZ', MIN_VERSIONS => '0', BLOCKCACHE => 'true', BLOCKSIZE => '65536', REPLICATION_SCOPE => '0'} {NAME => 'personal_info', BLOOMFILTER => 'ROW', VERSIONS => '2', IN_MEMORY => 'true', KEEP_DELETED_CELLS => 'FALSE', DATA_BLOCK_ENCODING => 'NO NE', TTL => 'FOREVER', COMPRESSION => 'GZ', MIN_VERSIONS => '0', BLOCKCACHE => 'true', BLOCKSIZE => '65536', REPLICATION_SCOPE => '0'} {NAME => 'professional_info', BLOOMFILTER => 'ROW', VERSIONS => '3', IN_MEMORY => 'false', KEEP_DELETED_CELLS => 'FALSE', DATA_BLOCK_ENCODING = > 'NONE', TTL => 'FOREVER', COMPRESSION => 'GZ', MIN_VERSIONS => '0', BLOCKCACHE => 'true', BLOCKSIZE => '65536', REPLICATION_SCOPE => '0'} - disable ’employee’ :
Always disable table before performing any DDL operation - alter ’employee’, {NAME => ‘col_fam1’, COMPRESSION => ‘GZ’}
With alter command you can add columns on fly as well as add different parameter to columns like storing IN_MEMORY , Setting compression for particular column family , setting number of versions etc. - list :
List all the tables stored in Hbase :
Example :
list
[“employee”, “table1”, “user_hcat_load_table”] - enable_all ‘t.*’ :
Enables all the table matching regex - exists ‘student’ :
Check weather student table exist or not - show_filters :
Shows all the available filter in Hbase - alter_status :
Get the status of the alter command. Indicates the number of regions of the table that have received the updated schema Pass table name. - alter_async :
Alter column family schema, does not wait for all regions to receive the
schema changes. Pass table name and a dictionary specifying new column
family schema. Dictionaries are described on the main help command output.
Dictionary must include name of column family to alter.
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_async ‘t1’, NAME => ‘f1’, VERSIONS => 5To delete the ‘f1’ column family in table ‘t1’, do:hbase> alter_async ‘t1’, NAME => ‘f1’, METHOD => ‘delete’or a shorter version:hbase> alter_async ‘t1’, ‘delete’ => ‘f1’
You can also change table-scope attributes like MAX_FILESIZE
MEMSTORE_FLUSHSIZE, READONLY, and DEFERRED_LOG_FLUSH.For example, to change the max size of a family to 128MB, do:
hbase> alter ‘t1’, METHOD => ‘table_att’, MAX_FILESIZE => ‘134217728’
There could be more than one alteration in one command:
hbase> alter ‘t1’, {NAME => ‘f1’}, {NAME => ‘f2’, METHOD => ‘delete’}
To check if all the regions have been updated, use alter_status <table_name>
- count :
Counts the number of rows in table. COUNT interval is by default 1000, one can increase the interval as well as set scan caching on count scan by default.
hbase> count ‘t1’, INTERVAL => 100000
hbase> count ‘t1’, CACHE => 1000
hbase> count ‘t1’, INTERVAL => 10, CACHE => 1000 - 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. To delete a cell from ‘t1’ at row ‘r1’ under column ‘c1’
marked with the time ‘ts1’, do:hbase> delete ‘t1’, ‘r1’, ‘c1’, ts1 - deleteall :
Delete all cells in a given row; pass a table name, row, and optionally
a column and timestamp. Examples:hbase> deleteall ‘t1’, ‘r1’
hbase> deleteall ‘t1’, ‘r1’, ‘c1’
hbase> deleteall ‘t1’, ‘r1’, ‘c1’, ts1 - get :
Get row or cell contents; pass table name, row, and optionally
a dictionary of column(s), timestamp, timerange and versions.
Examples:
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’, {FILTER => “ValueFilter(=, ‘binary:abc’)”}
hbase> get ‘t1’, ‘r1’, ‘c1’
hbase> get ‘t1’, ‘r1’, ‘c1’, ‘c2’
hbase> get ‘t1’, ‘r1’, [‘c1’, ‘c2’] - 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 - scan :
Scan a table; pass table name and optionally a dictionary of scanner
specifications. Scanner specifications may include one or more of:
TIMERANGE, FILTER, LIMIT, STARTROW, STOPROW, TIMESTAMP, MAXLENGTH,
or COLUMNS, CACHEIf 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:’.The filter can be specified in two ways:
1. Using a filterString – more information on this is available in the
Filter Language document attached to the HBASE-4176 JIRA
2. Using the entire package name of the filter.Some examples: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)} - truncate :
Disables, drops and recreates the specified table.
Examples:
hbase>truncate ‘t1’ Reference :
https://learnhbase.wordpress.com/2013/03/02/hbase-shell-commands/https://www.cloudera.com/documentation/enterprise/5-5-x/topics/admin_hbase_filtering.html
Bhavesh Gadoya 