Basic HBase Java Classes and Methods – Part 2: HBase Shell
Brian-Feenys-Mac-Pro:hbase-1.2.6 bfeeny$ hbase shell
2018-03-07 20:37:42,618 WARN util.NativeCodeLoader: Unable to load native-hadoop library for your platform... using builtin-java classes where applicable
SLF4J: Class path contains multiple SLF4J bindings.
SLF4J: Found binding in
SLF4J: Found binding in
SLF4J: See http://www.slf4j.org/codes.html#multiple_bindings for an explanation.
SLF4J: Actual binding is of type
HBase Shell; enter 'help<RETURN>' for list of supported commands.
Type "exit<RETURN>" to leave the HBase Shell
Version 1.2.6, rUnknown, Mon May 29 02:25:32 CDT 2017
hbase(main):001:0>
We can request the basic status from HBase
hbase(main):001:0> status
1 active master, 0 backup masters, 1 servers, 0 dead, 2.0000 average load
We ask it who we are, similar to the whoami UNIX command, and get a list of any tables
hbase(main):002:0> whoami
bfeeny (auth:SIMPLE)
groups: staff, everyone, localaccounts, _appserverusr, admin, _appserveradm, _lpadmin, _appstore, _lpoperator, _developer, _analyticsusers, com.apple.access_ftp, com.apple.access_screensharing, com.apple.access_ssh
hbase(main):005:0* list
TABLE
0 row(s) in 0.0450 seconds
=> []
We see that there are no tables. We create the employee table with two column families, personal and professional.
hbase(main):008:0> create 'employee', 'personal', 'professional'
0 row(s) in 1.2420 seconds
=> Hbase::Table - employee
hbase(main):009:0> list
TABLE
employee
1 row(s) in 0.0130 seconds
=> ["employee"]
We can use the describe command to give us more copious information about the table. Many of these parameters have to do with the underlaying Hadoop layer and are not important for our exercises.
hbase(main):010:0> describe 'employee'
Table employee is ENABLED
employee
COLUMN FAMILIES DESCRIPTION
{NAME => 'personal', BLOOMFILTER => 'ROW', VERSIONS => '1', IN_MEMORY => 'false', KEEP_DELETED_CELLS => 'FALSE', DATA_BLOCK_ENCODING => 'NONE', TTL => 'FOREVER', COMPRESSION =>
'NONE', MIN_VERSIONS => '0', BLOCKCACHE => 'true', BLOCKSIZE => '65536', REPLICATION_SCOPE => '0'}
{NAME => 'professional', BLOOMFILTER => 'ROW', VERSIONS => '1', IN_MEMORY => 'false', KEEP_DELETED_CELLS => 'FALSE', DATA_BLOCK_ENCODING => 'NONE', TTL => 'FOREVER', COMPRESSION
=> 'NONE', MIN_VERSIONS => '0', BLOCKCACHE => 'true', BLOCKSIZE => '65536', REPLICATION_SCOPE => '0'}
2 row(s) in 0.0300 seconds
We can see we have no actual records in the table
hbase(main):011:0> count 'employee'
0 row(s) in 0.0380 seconds
=> 0
Let's insert a single record with an ID (row key) of 1.
hbase(main):012:0> put 'employee', 1, 'personal:first_name', 'John'
0 row(s) in 0.0730 seconds
hbase(main):013:0> list
TABLE
employee
1 row(s) in 0.0130 seconds
=> ["employee"]
hbase(main):014:0> get 'employee', 1
COLUMN CELL
personal:first_name timestamp=1520557083015, value=John
1 row(s) in 0.0280 seconds
You can see we inserted a single record with a column first_name inside of the column family personal. There are no constraints in our table, so we can leave entire columns out or create new ones on the fly.
We will add a bunch more data
hbase(main):015:0> put 'employee', 3, 'personal:first_name', 'Sally'
0 row(s) in 0.0150 seconds
hbase(main):016:0> put 'employee', 3, 'personal:last_name', 'Jones'
0 row(s) in 0.0050 seconds
hbase(main):017:0> put 'employee', 3, 'personal:age', '32'
0 row(s) in 0.0030 seconds
hbase(main):018:0> put 'employee', 3, 'personal:gender', 'female'
0 row(s) in 0.0030 seconds
hbase(main):019:0> put 'employee', 3, 'personal:martial_status', 'divorced'
0 row(s) in 0.0040 seconds
hbase(main):020:0>
hbase(main):021:0* put 'employee', 3, 'professional:occupation', 'doctor'
0 row(s) in 0.0040 seconds
hbase(main):022:0> put 'employee', 3, 'professional:education', 'MD'
0 row(s) in 0.0030 seconds
Notice I inserted the above record using a row key that was not 2, instead I skipped 2. HBase doesn't care what you make the row key, it can be a string, number, even an array.
hbase(main):023:0> put 'employee', 2, 'personal:first_name', 'Alex'
0 row(s) in 0.0150 seconds
hbase(main):024:0> put 'employee', 2, 'personal:last_name', 'Wright'
0 row(s) in 0.0050 seconds
hbase(main):025:0> put 'employee', 2, 'personal:age', '24'
0 row(s) in 0.0030 seconds
hbase(main):026:0> put 'employee', 2, 'personal:gender', 'male'
0 row(s) in 0.0030 seconds
hbase(main):027:0> put 'employee', 2, 'personal:martial_status', 'single'
0 row(s) in 0.0030 seconds
hbase(main):028:0>
hbase(main):029:0* put 'employee', 2, 'professional:occupation', 'cab driver'
0 row(s) in 0.0030 seconds
hbase(main):030:0> put 'employee', 2, 'professional:education', 'high school'
0 row(s) in 0.0140 seconds
Now that we have inserted information regarding three employees, lets take a look at our table.
hbase(main):031:0> count 'employee'
3 row(s) in 0.0170 seconds
=> 3
hbase(main):032:0> scan 'employee'
ROW COLUMN+CELL
1 column=personal:first_name, timestamp=1520557083015, value=John
2 column=personal:age, timestamp=1520557533759, value=24
2 column=personal:first_name, timestamp=1520557533683, value=Alex
2 column=personal:gender, timestamp=1520557533790, value=male
2 column=personal:last_name, timestamp=1520557533725, value=Wright
2 column=personal:martial_status, timestamp=1520557533821, value=single
2 column=professional:education, timestamp=1520557553040, value=high school
2 column=professional:occupation, timestamp=1520557533875, value=cab driver
3 column=personal:age, timestamp=1520557387868, value=32
3 column=personal:first_name, timestamp=1520557387787, value=Sally
3 column=personal:gender, timestamp=1520557387897, value=female
3 column=personal:last_name, timestamp=1520557387827, value=Jones
3 column=personal:martial_status, timestamp=1520557387926, value=divorced
3 column=professional:education, timestamp=1520557388005, value=MD
3 column=professional:occupation, timestamp=1520557387976, value=doctor
3 row(s) in 0.0310 seconds
We can easily make changes to any information:
hbase(main):034:0> put 'employee', 3, 'personal:martial_status', 'married'
0 row(s) in 0.0150 seconds
hbase(main):035:0> get 'employee', 3
COLUMN CELL
personal:age timestamp=1520557387868, value=32
personal:first_name timestamp=1520557387787, value=Sally
personal:gender timestamp=1520557387897, value=female
personal:last_name timestamp=1520557387827, value=Jones
personal:martial_status timestamp=1520557942262, value=married
professional:education timestamp=1520557388005, value=MD
professional:occupation timestamp=1520557387976, value=doctor
7 row(s) in 0.0050 seconds
We can delete just a single cell if we wish
hbase(main):044:0> delete 'employee', 1, 'personal:martial_status'
0 row(s) in 0.0140 seconds
hbase(main):045:0> get 'employee', 1
COLUMN CELL
personal:age timestamp=1520558063384, value=50
personal:first_name timestamp=1520558063320, value=John
personal:gender timestamp=1520558063410, value=male
personal:last_name timestamp=1520558063358, value=Smith
4 row(s) in 0.0130 seconds
We can use the exists command to see if a table exists
hbase(main):046:0> exists 'employee'
Table employee does exist
0 row(s) in 0.0180 seconds
We have to disable a table before we can drop it. Disabling a table flushes all the data in memory to disk.
hbase(main):047:0> disable 'employee'
0 row(s) in 2.2590 seconds
hbase(main):048:0> enable 'employee'
0 row(s) in 1.2500 seconds
hbase(main):049:0> drop 'employee'
ERROR: Table employee is enabled. Disable it first.
Here is some help for this command:
Drop the named table. Table must first be disabled:
hbase> drop 't1'
hbase> drop 'ns1:t1'
hbase(main):050:0> disable 'employee'
0 row(s) in 2.2350 seconds
hbase(main):051:0> drop 'employee'
0 row(s) in 1.2380 seconds
We can see there are no more tables
hbase(main):052:0> list
TABLE
0 row(s) in 0.0010 seconds
=> []
We will be repeating these commands in the next Part using Java in Basic HBase Java Classes and Methods – Part 3: Table CreationRecent Posts
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