hbase的四种压缩格式-创新互联
Hbase支持的压缩格式：
hbase支持的压缩格式：GZ（GZIP）,LZ0，LZ4，Snappy
GZ:用于冷数据压缩，与Snappy和LZ0相比，GZIP的压缩率更高，但是更消耗CPU，解压/压缩速度更慢。
Snappy和LZ0：用于热数据压缩，占用CPU少，解压/压缩速度比GZ快，但是压缩率不如GZ高。
Snappy与LZ0相比，Snappy整体性能优于LZ0，Snappy压缩率比LZ0更低，但是解压/压缩速度更快。
LZ4与LZ0相比，LZ4的压缩率和LZ0的压缩率相差不多，但是LZ4的解压/压缩速度更快。
多数情况下，选择Snppy或LZ0是比较好的选择，因为它们的压缩开销底，能节省空间。
建表时指定压缩格式
hbase(main):013:0> create 'test3',{NAME=>'f1'},{NAME=>'f2',COMPRESSION=>'Snappy'}
0 row(s) in 1.2740 seconds
=> Hbase::Table - test3
hbase(main):014:0> desc 'test3'
Table test3 is ENABLED
test3
COLUMN FAMILIES DESCRIPTION
{NAME => 'f1', BLOOMFILTER => 'ROW',VERSIONS => '1', IN_MEMORY => 'false', KEEP_DELETED_CELLS => 'FALSE',DATA_BLOCK_ENCODING => 'NONE', TTL => 'FOREVER', COMPRESS
ION => 'NONE', MIN_VERSIONS => '0',BLOCKCACHE => 'true', BLOCKSIZE => '65536', REPLICATION_SCOPE =>'0'}
{NAME => 'f2', BLOOMFILTER => 'ROW',VERSIONS => '1', IN_MEMORY => 'false', KEEP_DELETED_CELLS => 'FALSE',DATA_BLOCK_ENCODING => 'NONE', TTL => 'FOREVER', COMPRESS
ION => 'SNAPPY', MIN_VERSIONS => '0',BLOCKCACHE => 'true', BLOCKSIZE => '65536', REPLICATION_SCOPE =>'0'}
2 row(s) in 0.0300 seconds
hbase(main):002:0> create 'test4' ,{NAME=>'f1'},{NAME=>'f2',COMPRESSION=>'GZ'}
0 row(s) in 1.4900 seconds
=> Hbase::Table - test4
hbase(main):003:0> desc 'test4'
Table test4 is ENABLED
test4
COLUMN FAMILIES DESCRIPTION
{NAME => 'f1', BLOOMFILTER => 'ROW', VERSIONS => '1', IN_MEMORY => 'false', KEEP_DELETED_CELLS => 'FALSE', DATA_BLOCK_ENCODING => 'NONE', TTL => 'FOREVER', COMPRESS
ION => 'NONE', MIN_VERSIONS => '0', BLOCKCACHE => 'true', BLOCKSIZE => '65536', REPLICATION_SCOPE => '0'}
{NAME => 'f2', BLOOMFILTER => 'ROW', VERSIONS => '1', IN_MEMORY => 'false', KEEP_DELETED_CELLS => 'FALSE', DATA_BLOCK_ENCODING => 'NONE', TTL => 'FOREVER', COMPRESS
ION => 'GZ', MIN_VERSIONS => '0', BLOCKCACHE => 'true', BLOCKSIZE => '65536', REPLICATION_SCOPE => '0'}
2 row(s) in 0.1290 seconds建表后修改columnfamily压缩格式
正确做法是先disable表，再修改列族压缩格式，enbale表后做major_compact操作。
如下：
hbase(main):004:0> desc 'test1'
Table test1 is ENABLED
test1
COLUMN FAMILIES DESCRIPTION
{NAME => 'f1', BLOOMFILTER => 'ROW',VERSIONS => '1', IN_MEMORY => 'false', KEEP_DELETED_CELLS => 'FALSE',DATA_BLOCK_ENCODING => 'NONE', TTL => 'FOREVER', COMPRESS
ION => 'NONE', MIN_VERSIONS => '0',BLOCKCACHE => 'true', BLOCKSIZE => '65536', REPLICATION_SCOPE =>'0'}
{NAME => 'f2', BLOOMFILTER => 'ROW',VERSIONS => '1', IN_MEMORY => 'false', KEEP_DELETED_CELLS => 'FALSE',DATA_BLOCK_ENCODING => 'NONE', TTL => 'FOREVER', COMPRESS
ION => 'NONE', MIN_VERSIONS => '0',BLOCKCACHE => 'true', BLOCKSIZE => '65536', REPLICATION_SCOPE =>'0'}
2 row(s) in 0.0230 seconds
hbase(main):005:0> disable 'test1'
0 row(s) in 2.2870 seconds
hbase(main):006:0> alter 'test1' ,{NAME=>'f1',COMPRESSION=>'Snappy'}
Updating all regions with the new schema...
1/1 regions updated.
Done.
0 row(s) in 1.9510 seconds
hbase(main):007:0> enable 'test1'
0 row(s) in 1.2820 seconds
hbase(main):008:0> desc 'test1'
Table test1 is ENABLED
test1
COLUMN FAMILIES DESCRIPTION
{NAME => 'f1', BLOOMFILTER => 'ROW',VERSIONS => '1', IN_MEMORY => 'false', KEEP_DELETED_CELLS => 'FALSE',DATA_BLOCK_ENCODING => 'NONE', TTL => 'FOREVER', COMPRESS
ION => 'SNAPPY', MIN_VERSIONS => '0',BLOCKCACHE => 'true', BLOCKSIZE => '65536', REPLICATION_SCOPE =>'0'}
{NAME => 'f2', BLOOMFILTER => 'ROW',VERSIONS => '1', IN_MEMORY => 'false', KEEP_DELETED_CELLS => 'FALSE',DATA_BLOCK_ENCODING => 'NONE', TTL => 'FOREVER', COMPRESS
ION => 'NONE', MIN_VERSIONS => '0',BLOCKCACHE => 'true', BLOCKSIZE => '65536', REPLICATION_SCOPE =>'0'}
2 row(s) in 0.0310 seconds
hbase(main):009:0> major_compact 'test1'
0 row(s) in 0.1380 seconds
hbase(main):010:0> desc 'test1'
Table test1 is ENABLED
test1
COLUMN FAMILIES DESCRIPTION
{NAME => 'f1', BLOOMFILTER => 'ROW',VERSIONS => '1', IN_MEMORY => 'false', KEEP_DELETED_CELLS => 'FALSE',DATA_BLOCK_ENCODING => 'NONE', TTL => 'FOREVER', COMPRESS
ION => 'SNAPPY', MIN_VERSIONS => '0',BLOCKCACHE => 'true', BLOCKSIZE => '65536', REPLICATION_SCOPE =>'0'}
{NAME => 'f2', BLOOMFILTER => 'ROW',VERSIONS => '1', IN_MEMORY => 'false', KEEP_DELETED_CELLS => 'FALSE',DATA_BLOCK_ENCODING => 'NONE', TTL => 'FOREVER', COMPRESS
ION => 'NONE', MIN_VERSIONS => '0',BLOCKCACHE => 'true', BLOCKSIZE => '65536', REPLICATION_SCOPE =>'0'}
2 row(s) in 0.0260 seconds但是没有disable表，也不做major_compact，列族压缩格式也修改成功了（暂时不知道原因）。
hbase(main):001:0> desc 'test'
Table test is ENABLED
test
COLUMN FAMILIES DESCRIPTION
{NAME => 'fam1', BLOOMFILTER => 'ROW', VERSIONS => '1', IN_MEMORY => 'false', KEEP_DELETED_CELLS => 'FALSE', DATA_BLOCK_ENCODING => 'NONE', TTL => 'FOREVER', COMPRE
SSION => 'NONE', MIN_VERSIONS => '0', BLOCKCACHE => 'true', BLOCKSIZE => '65536', REPLICATION_SCOPE => '0'}
1 row(s) in 0.3680 seconds
hbase(main):002:0> alter 'test',{NAME=>'fam1',COMPRESSION=>'LZ4'}
Updating all regions with the new schema...
1/1 regions updated.
Done.
0 row(s) in 2.0460 seconds
hbase(main):003:0> desc 'test'
Table test is ENABLED
test
COLUMN FAMILIES DESCRIPTION
{NAME => 'fam1', BLOOMFILTER =>'ROW', VERSIONS => '1', IN_MEMORY => 'false', KEEP_DELETED_CELLS =>'FALSE', DATA_BLOCK_ENCODING => 'NONE', TTL => 'FOREVER', COMPRE
SSION => 'LZ4', MIN_VERSIONS => '0',BLOCKCACHE => 'true', BLOCKSIZE => '65536', REPLICATION_SCOPE =>'0'}
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