hbase查询,scan详解

一、shell 查询

hbase 查询相当简单，提供了get和scan两种方式，也不存在多表联合查询的问题。复杂查询需通过hive创建相应外部表，用sql语句自动生成mapreduce进行。
但是这种简单，有时为了达到目的，也不是那么顺手。至少和sql查询方式相差较大。

hbase 提供了很多过滤器，可对行键，列，值进行过滤。过滤方式可以是子串，二进制，前缀，正则比较等。条件可以是AND,OR等 组合。所以通过过滤，还是能满足需求，找到正确的结果的。

1.1 过滤器类型

HBase 最新官方文档中文版(http://abloz.com/hbase/book.html)中有对过滤器的描述。过滤器分为5种类型：

1. 构造型过滤器：用于包含其他一组过滤器的过滤器。包括：FilterList
2. 列值型过滤器：对每列的值进行过滤的. 相当于sql查询中的=和like 包括：

   SingleColumnValueFilter

   比较器，包括：
   RegexStringComparator 支持值比较的正则表达式
   SubstringComparator 用于检测一个子串是否存在于值中。大小写不敏感。 
   BinaryPrefixComparator 二进制前缀比较
   BinaryComparator 二进制比较

3. 键值元数据过滤器：用于对列进行过滤的。包括：

   FamilyFilter 用于过滤列族。 通常，在Scan中选择ColumnFamilie优于在过滤器中做。
   QualifierFilter 用于基于列名(即 Qualifier)过滤.
   ColumnPrefixFilter 可基于列名(即Qualifier)前缀过滤。
   MultipleColumnPrefixFilter 和 ColumnPrefixFilter 行为差不多，但可以指定多个前缀。
   ColumnRangeFilter 可以进行高效内部扫描。  

4. Rowkey：对行键进行过滤。通常认为行选择时Scan采用 startRow/stopRow 方法比较好。然而 RowFilter 也可以用。
5. 工具：如FirstKeyOnlyFilter用于统计行数。

二、示例

1.FirstKeyOnlyFilter,一种方便的计算行数的过滤器

hbase(main):002:0> scan 'toplist_ware_ios_1009_201231',{COLUMNS=>'info',FILTER=>"(FirstKeyOnlyFilter())"}
 0000000001                       column=info:loginid, timestamp=1343625459713, value=jjm168131013
 0000000002                       column=info:loginid, timestamp=1343625459713, value=loveswh
...
21 row(s) in 0.5480 seconds

2.列名子串进行过滤

hbase(main):006:0> scan 'toplist_ware_ios_1009_201231',{COLUMNS=>['info:'],FILTER=>"(QualifierFilter(=,'substring:id'))"}
ROW COLUMN+CELL
0000000001 column=info:loginid, timestamp=1343625459713, value=jjm168131013
0000000001 column=info:userid, timestamp=1343625459713, value=168131013
0000000002 column=info:loginid, timestamp=1343625459713, value=loveswh
0000000002 column=info:userid, timestamp=1343625459713, value=100898152

hbase(main):005:0> scan 'toplist_ware_ios_1009_201231',{COLUMNS=>['info:loginid'],FILTER=>"(QualifierFilter(=,'substring:id'))"}
ROW COLUMN+CELL
0000000001 column=info:loginid, timestamp=1343625459713, value=jjm168131013
0000000002 column=info:loginid, timestamp=1343625459713, value=loveswh

hbase(main):007:0> scan 'toplist_ware_ios_1009_201231',{COLUMNS=>['info:'],FILTER=>"(QualifierFilter(=,'substring:nid'))"}
ROW COLUMN+CELL
0000000001 column=info:loginid, timestamp=1343625459713, value=jjm168131013
0000000002 column=info:loginid, timestamp=1343625459713, value=loveswh

hbase(main):008:0> scan 'toplist_ware_ios_1009_201231',{COLUMNS=>['info:'],FILTER=>"(QualifierFilter(=,'substring:nick'))"}
ROW COLUMN+CELL
0000000001 column=info:nick, timestamp=1343625459713, value=xE5xAExB6xE6x9Cx89xE8x99x8ExE5xAEx9
D
0000000002 column=info:nick, timestamp=1343625459713, value=loveswh08

3.Value 过滤

3.1 正则过滤
hbase(main):004:0> scan 'toplist_ware_ios_1009_201231',{COLUMNS=>'info',FILTER=>"(SingleColumnValueFilter('info','nick',=,'regexstring:.*99',true,true))"}
ROW                               COLUMN+CELL
 0000000009                       column=info:loginid, timestamp=1343625459713, value=zgh1968
 0000000009                       column=info:nick, timestamp=1343625459713, value=zwy99
 0000000009                       column=info:score, timestamp=1343625459713, value=5
 0000000009                       column=info:userid, timestamp=1343625459713, value=100366262
1 row(s) in 0.2520 seconds

3.2 子串
需导入
import org.apache.hadoop.hbase.filter.CompareFilter
import org.apache.hadoop.hbase.filter.SingleColumnValueFilter
import org.apache.hadoop.hbase.filter.SubstringComparator
import org.apache.hadoop.hbase.util.Bytes

hbase(main):028:0> scan 'toplist_ware_ios_1001_201231',{COLUMNS =>'info:nick', FILTER=>SingleColumnValueFilter.new(Bytes.toBytes('info'),Bytes.toBytes('nick'),CompareFilter::CompareOp.valueOf('EQUAL'),SubstringComparator.new('8888'))}
ROW COLUMN+CELL
0000000002 column=info:nick, timestamp=1343625446556, value=xE7x81x8F????xE3x81x8A??8888
1 row(s) in 0.0330 seconds

3.3 二进制
子串等不支持多字节文字，所以用二进制来进行比较
hbase(main):010:0> scan 'toplist_ware_ios_1009_201231',{COLUMNS=>['info:'],FILTER=>"(QualifierFilter(=,'substring:nick') AND ValueFilter(=,'binary:7789xE6xB4x81') )"}
ROW COLUMN+CELL
0000000016 column=info:nick, timestamp=1343625459713, value=7789xE6xB4x81
1 row(s) in 0.1710 seconds

4 综合列名子串和值二进制比较

hbase(main):012:0> scan 'toplist_ware_ios_1009_201231',{COLUMNS=>['info:'],FILTER=>"(QualifierFilter(=,'substring:nick') AND ValueFilter(=,'binary:7789xE6xB4x81') )"}
ROW COLUMN+CELL
0000000016 column=info:nick, timestamp=1343625459713, value=7789xE6xB4x81
1 row(s) in 0.0120 seconds

hbase(main):014:0> scan 'toplist_ware_ios_1009_201231',{COLUMNS=>"info:",FILTER=>"(PrefixFilter('000000002')) AND (QualifierFilter(=,'substring:nick')"}
ROW COLUMN+CELL
 0000000020 column=info:nick, timestamp=1343625459713, value=Denny_feng
 0000000021 column=info:nick, timestamp=1343625459713, value=xE5xB0x8FxE7xBDx97xE6x95x99xE7xBBx8
 31
2 row(s) in 0.0440 seconds

5. 行查询

hbase(main):005:0> get 'toplist_ware_ios_1009_201231','0000000009'
COLUMN CELL
 info:loginid timestamp=1343625459713, value=zgh1968
 info:nick timestamp=1343625459713, value=zwy99
 info:score timestamp=1343625459713, value=5
 info:userid timestamp=1343625459713, value=100366262
4 row(s) in 0.1000 seconds

hbase(main):006:0> get 'toplist_ware_ios_1009_201231','0000000009','info:nick'
COLUMN CELL
 info:nick timestamp=1343625459713, value=zwy99
1 row(s) in 0.0100 seconds

hbase(main):009:0> scan 'toplist_ware_ios_1009_201231',FILTER=>"PrefixFilter('000000002')"
ROW COLUMN+CELL
 0000000020 column=info:loginid, timestamp=1343625459713, value=jjm169212318
 0000000020 column=info:nick, timestamp=1343625459713, value=Denny_feng
 0000000020 column=info:score, timestamp=1343625459713, value=1
 0000000020 column=info:userid, timestamp=1343625459713, value=169212318
 0000000021 column=info:loginid, timestamp=1343625459713, value=jjm169371841
 0000000021 column=info:nick, timestamp=1343625459713, value=xE5xB0x8FxE7xBDx97xE6x95x99xE7xBBx8
 31
 0000000021 column=info:score, timestamp=1343625459713, value=1
 0000000021 column=info:userid, timestamp=1343625459713, value=169371841
2 row(s) in 0.0180 seconds

hbase(main):010:0> scan 'toplist_ware_ios_1009_201231',FILTER=>"PrefixFilter('000000002')",LIMIT=>1
ROW COLUMN+CELL
 0000000020 column=info:loginid, timestamp=1343625459713, value=jjm169212318
 0000000020 column=info:nick, timestamp=1343625459713, value=Denny_feng
 0000000020 column=info:score, timestamp=1343625459713, value=1
 0000000020 column=info:userid, timestamp=1343625459713, value=169212318
1 row(s) in 0.0170 seconds

hbase(main):011:0> scan 'toplist_ware_ios_1009_201231',{COLUMNS=>"info:nick",FILTER=>"PrefixFilter('000000002')",LIMIT=>1}
ROW COLUMN+CELL
 0000000020 column=info:nick, timestamp=1343625459713, value=Denny_feng
1 row(s) in 0.0160 seconds