hbase权威指南阅读随手笔记二之过滤器
base过滤器的比较操作符：
2.1 SingleColumnValueFilter
LESS <
LESS_OR_EQUAL <=
EQUAL =
NOT_EQUAL <>
GREATER_OR_EQUAL >=
GREATER >
NO_OP no operation
比较器：
Hbase的过滤器分类
BinaryComparator 按字节索引顺序比较指定字节数组，采用Bytes.compareTo(byte[])
BinaryPrefixComparator 跟前面相同，只是比较左端的数据是否相同
NullComparator 判断给定的是否为空
BitComparator 按位比较 a BitwiseOp class 做异或，与，并操作
RegexStringComparator 提供一个正则的比较器，仅支持 EQUAL 和非EQUALSubstringComparator 判断提供的子串是否出现在table的value中。
比较过滤器
1、Comparision Filters
1.1 RowFilter
1.1 RowFilter
构造函数public RowFilter(org.apache.hadoop.hbase.filter.CompareFilter.CompareOp rowCompareOp, org.apache.hadoop.hbase.filter.WritableByteArrayComparable rowComparator) {}选择比较rowkey来确定选择合适的行信息。
1.2 FamilyFilterpublic class RowFilterExample { public static void main(String[] args) throws IOException { Configuration conf = HBaseConfiguration.create(); HBaseHelper helper = HBaseHelper.getHelper(conf); helper.dropTable("testtable"); helper.createTable("testtable", "colfam1", "colfam2"); System.out.println("Adding rows to table..."); helper.fillTable("testtable", 1, 100, 100, "colfam1", "colfam2"); HTable table = new HTable(conf, "testtable"); // vv RowFilterExample Scan scan = new Scan(); scan.addColumn(Bytes.toBytes("colfam1"), Bytes.toBytes("col-0")); Filter filter1 = new RowFilter(CompareFilter.CompareOp.LESS_OR_EQUAL, // co RowFilterExample-1-Filter1 Create filter, while specifying the comparison operator and comparator. Here an exact match is needed. new BinaryComparator(Bytes.toBytes("row-22"))); scan.setFilter(filter1); ResultScanner scanner1 = table.getScanner(scan); // ^^ RowFilterExample System.out.println("Scanning table #1..."); // vv RowFilterExample for (Result res : scanner1) { System.out.println(res); } scanner1.close(); Filter filter2 = new RowFilter(CompareFilter.CompareOp.EQUAL, // co RowFilterExample-2-Filter2 Another filter, this time using a regular expression to match the row keys. new RegexStringComparator(".*-.5")); scan.setFilter(filter2); ResultScanner scanner2 = table.getScanner(scan); // ^^ RowFilterExample System.out.println("Scanning table #2..."); // vv RowFilterExample for (Result res : scanner2) { System.out.println(res); } scanner2.close(); Filter filter3 = new RowFilter(CompareFilter.CompareOp.EQUAL, // co RowFilterExample-3-Filter3 The third filter uses a substring match approach. new SubstringComparator("-5")); scan.setFilter(filter3); ResultScanner scanner3 = table.getScanner(scan); // ^^ RowFilterExample System.out.println("Scanning table #3..."); // vv RowFilterExample for (Result res : scanner3) { System.out.println(res); } scanner3.close(); // ^^ RowFilterExample } }
构造函数
public FamilyFilter(CompareOp familyCompareOp, WritableByteArrayComparable familyComparator) {}
通过和列簇比较得到，返回结果为真的数据，示例：
public class FamilyFilterExample { public static void main(String[] args) throws IOException { Configuration conf = HBaseConfiguration.create(); HBaseHelper helper = HBaseHelper.getHelper(conf); helper.dropTable("testtable"); helper.createTable("testtable", "colfam1", "colfam2", "colfam3", "colfam4"); System.out.println("Adding rows to table..."); helper.fillTable("testtable", 1, 10, 2, "colfam1", "colfam2", "colfam3", "colfam4"); HTable table = new HTable(conf, "testtable"); // vv FamilyFilterExample Filter filter1 = new FamilyFilter(CompareFilter.CompareOp.LESS, // co FamilyFilterExample-1-Filter Create filter, while specifying the comparison operator and comparator. new BinaryComparator(Bytes.toBytes("colfam3"))); Scan scan = new Scan(); scan.setFilter(filter1); ResultScanner scanner = table.getScanner(scan); // co FamilyFilterExample-2-Scan Scan over table while applying the filter. // ^^ FamilyFilterExample System.out.println("Scanning table... "); // vv FamilyFilterExample for (Result result : scanner) { System.out.println(result); } scanner.close(); Get get1 = new Get(Bytes.toBytes("row-5")); get1.setFilter(filter1); Result result1 = table.get(get1); // co FamilyFilterExample-3-Get Get a row while applying the same filter. System.out.println("Result of get(): " + result1); Filter filter2 = new FamilyFilter(CompareFilter.CompareOp.EQUAL, new BinaryComparator(Bytes.toBytes("colfam3"))); Get get2 = new Get(Bytes.toBytes("row-5")); // co FamilyFilterExample-4-Mismatch Create a filter on one column family while trying to retrieve another. get2.addFamily(Bytes.toBytes("colfam1")); get2.setFilter(filter2); Result result2 = table.get(get2); // co FamilyFilterExample-5-Get2 Get the same row while applying the new filter, this will return "NONE". System.out.println("Result of get(): " + result2); // ^^ FamilyFilterExample } }
1.3 QualifierFilter
1.4 ValueFilter构造函数public QualifierFilter(CompareOp qualifierCompareOp, WritableByteArrayComparable qualifierComparator) { }通过和列名比较，返回为真的数据，示例：// vv QualifierFilterExample Filter filter = new QualifierFilter(CompareFilter.CompareOp.LESS_OR_EQUAL, new BinaryComparator(Bytes.toBytes("col-2"))); Scan scan = new Scan(); scan.setFilter(filter); ResultScanner scanner = table.getScanner(scan); // ^^ QualifierFilterExample System.out.println("Scanning table... "); // vv QualifierFilterExample for (Result result : scanner) { System.out.println(result); } scanner.close(); Get get = new Get(Bytes.toBytes("row-5")); get.setFilter(filter); Result result = table.get(get); System.out.println("Result of get(): " + result);
构造函数public ValueFilter(CompareOp valueCompareOp, WritableByteArrayComparable valueComparator) {}通过和列名比较，返回为真的数据，示例：Filter filter = new ValueFilter(CompareFilter.CompareOp.EQUAL, // co ValueFilterExample-1-Filter Create filter, while specifying the comparison operator and comparator. new SubstringComparator(".4") ); Scan scan = new Scan(); scan.setFilter(filter); // co ValueFilterExample-2-SetFilter Set filter for the scan. ResultScanner scanner = table.getScanner(scan); // ^^ ValueFilterExample System.out.println("Results of scan:"); // vv ValueFilterExample for (Result result : scanner) { for (KeyValue kv : result.raw()) { System.out.println("KV: " + kv + ", Value: " + // co ValueFilterExample-3-Print1 Print out value to check that filter works. Bytes.toString(kv.getValue())); } } scanner.close(); Get get = new Get(Bytes.toBytes("row-5")); get.setFilter(filter); // co ValueFilterExample-4-SetFilter2 Assign same filter to Get instance. Result result = table.get(get); // ^^ ValueFilterExample System.out.println("Result of get: "); // vv ValueFilterExample for (KeyValue kv : result.raw()) { System.out.println("KV: " + kv + ", Value: " + Bytes.toString(kv.getValue())); }
1.5 DependentColumnFilter
该过滤器有两个参数 —— 列族和列修饰。 尝试找到该列所在的每一行，并返回该行具有相同时间戳的全部键值对。如果某一行不包含指定的列，则该行的任何键值对都不返回。
该过滤器还可以有一个可选布尔参数 —— dropDependentColumn. 如果为true, 从属的列不返回。
该过滤器还可以有两个可选参数 —— 一个比较操作符和一个值比较器，用于列族和修饰的进一步检查。如果从属的列找到，其值还必须通过值检查，然后就是时间戳必须考虑。
2、Dedicated Filterspackage filters; // cc DependentColumnFilterExample Example using a filter to include only specific column families import org.apache.hadoop.conf.Configuration; import org.apache.hadoop.hbase.HBaseConfiguration; import org.apache.hadoop.hbase.KeyValue; import org.apache.hadoop.hbase.client.Get; import org.apache.hadoop.hbase.client.HTable; import org.apache.hadoop.hbase.client.Result; import org.apache.hadoop.hbase.client.ResultScanner; import org.apache.hadoop.hbase.client.Scan; import org.apache.hadoop.hbase.filter.BinaryPrefixComparator; import org.apache.hadoop.hbase.filter.CompareFilter; import org.apache.hadoop.hbase.filter.DependentColumnFilter; import org.apache.hadoop.hbase.filter.Filter; import org.apache.hadoop.hbase.filter.RegexStringComparator; import org.apache.hadoop.hbase.filter.WritableByteArrayComparable; import org.apache.hadoop.hbase.util.Bytes; import util.HBaseHelper; import java.io.IOException; public class DependentColumnFilterExample { private static HTable table = null; // vv DependentColumnFilterExample private static void filter(boolean drop, CompareFilter.CompareOp operator, WritableByteArrayComparable comparator) throws IOException { Filter filter; if (comparator != null) { filter = new DependentColumnFilter(Bytes.toBytes("colfam1"), // co DependentColumnFilterExample-1-CreateFilter Create the filter with various options. Bytes.toBytes("col-5"), drop, operator, comparator); } else { filter = new DependentColumnFilter(Bytes.toBytes("colfam1"), Bytes.toBytes("col-5"), drop); } Scan scan = new Scan(); scan.setFilter(filter); ResultScanner scanner = table.getScanner(scan); // ^^ DependentColumnFilterExample System.out.println("Results of scan:"); // vv DependentColumnFilterExample for (Result result : scanner) { for (KeyValue kv : result.raw()) { System.out.println("KV: " + kv + ", Value: " + Bytes.toString(kv.getValue())); } } scanner.close(); Get get = new Get(Bytes.toBytes("row-5")); get.setFilter(filter); Result result = table.get(get); // ^^ DependentColumnFilterExample System.out.println("Result of get: "); // vv DependentColumnFilterExample for (KeyValue kv : result.raw()) { System.out.println("KV: " + kv + ", Value: " + Bytes.toString(kv.getValue())); } // ^^ DependentColumnFilterExample System.out.println(""); // vv DependentColumnFilterExample } public static void main(String[] args) throws IOException { // ^^ DependentColumnFilterExample Configuration conf = HBaseConfiguration.create(); HBaseHelper helper = HBaseHelper.getHelper(conf); helper.dropTable("testtable"); helper.createTable("testtable", "colfam1", "colfam2"); System.out.println("Adding rows to table..."); helper.fillTable("testtable", 1, 10, 10, true, "colfam1", "colfam2"); table = new HTable(conf, "testtable"); // vv DependentColumnFilterExample filter(true, CompareFilter.CompareOp.NO_OP, null); filter(false, CompareFilter.CompareOp.NO_OP, null); // co DependentColumnFilterExample-2-Filter Call filter method with various options. filter(true, CompareFilter.CompareOp.EQUAL, new BinaryPrefixComparator(Bytes.toBytes("val-5"))); filter(false, CompareFilter.CompareOp.EQUAL, new BinaryPrefixComparator(Bytes.toBytes("val-5"))); filter(true, CompareFilter.CompareOp.EQUAL, new RegexStringComparator(".*\\.5")); filter(false, CompareFilter.CompareOp.EQUAL, new RegexStringComparator(".*\\.5")); } // ^^ DependentColumnFilterExample}
2.1 SingleColumnValueFilter
选定列簇和某一列，然后与列的value相比，正确的返回全部的row，注意如果某一行不含有该列，同样返回，除非通过filterIfColumnMissing 设置成真。
构造函数
SingleColumnValueFilter(byte[] family, byte[] qualifier, CompareOp compareOp, byte[] value) SingleColumnValueFilter(byte[] family, byte[] qualifier, CompareOp compareOp, WritableByteArrayComparable comparator)第一个构造函数相当于构建了一个BinaryComparator的实例。其他的跟CompareFilter的参数含义一样。
该过滤器通过下面两个参数 filterIfMissing,latestVersionOnly
boolean getFilterIfMissing() void setFilterIfMissing(boolean filterIfMissing) boolean getLatestVersionOnly() void setLatestVersionOnly(boolean latestVersionOnly)如果 filterIfColumnMissing 标志设为真，如果该行没有指定的列，那么该行的所有列将不发出。缺省值为假。
如果setLatestVersionOnly 标志设为假，将检查此前的版本。缺省值为真。实例如下：
// vv SingleColumnValueFilterExample
SingleColumnValueFilter filter = new SingleColumnValueFilter(
Bytes.toBytes("colfam1"),
Bytes.toBytes("col-5"),
CompareFilter.CompareOp.NOT_EQUAL,
new SubstringComparator("val-5"));
filter.setFilterIfMissing(true);
Scan scan = new Scan();
scan.setFilter(filter);
ResultScanner scanner = table.getScanner(scan);
// ^^ SingleColumnValueFilterExample
System.out.println("Results of scan:");
// vv SingleColumnValueFilterExample
for (Result result : scanner) {
for (KeyValue kv : result.raw()) {
System.out.println("KV: " + kv + ", Value: " +
Bytes.toString(kv.getValue()));
}
}
scanner.close();
Get get = new Get(Bytes.toBytes("row-6"));
get.setFilter(filter);
Result result = table.get(get);
System.out.println("Result of get: ");
for (KeyValue kv : result.raw()) {
System.out.println("KV: " + kv + ", Value: " +
Bytes.toString(kv.getValue()));
}
2.2 SingleColumnValueExcludeFilter
该过滤器同上面的过滤器正好相反，如果条件相符，将不会返回该列的内容。
2.3 PrefixFilter
所有的row的实例匹配prefix的时候返回结果集合
2.4 PageFilterFilter filter = new PrefixFilter(Bytes.toBytes("row1")); Scan scan = new Scan(); scan.setFilter(filter); ResultScanner scanner = table.getScanner(scan); for(Result result: scanner){ for(KeyValue kv: result.raw()) { System.out.println("KV:" + kv + ", Value:" + Bytes.toString(kv.getValue())); } } scanner.close(); Get get = new Get(Bytes.toBytes("row-5")); get.setFilter(filter); Result result = table.get(get); for(KeyValue kv : result.raw()){ System.out.println("KV:" + kv + ", Value:" + Bytes.toString(kv.getValue())); }
页过滤，通过设置pagesize参数可以返回每一页page的数量。
客户端需要记住上一次访问的row的key值。
package hbaseTest;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.hbase.HBaseConfiguration;
import org.apache.hadoop.hbase.client.HTable;
import org.apache.hadoop.hbase.client.Result;
import org.apache.hadoop.hbase.client.ResultScanner;
import org.apache.hadoop.hbase.client.Scan;
import org.apache.hadoop.hbase.filter.Filter;
import org.apache.hadoop.hbase.filter.PageFilter;
import org.apache.hadoop.hbase.util.Bytes;
import java.io.IOException;
/**
* Hello world!
*/
public class PageFilterExample {
public static void main(String[] args) throws IOException {
Configuration config = HBaseConfiguration.create();
config.set("hbase.zookeeper.quorum", "QT-H-0038");
String tableName = "testTable";
String cfName = "colfam1";
final byte[] POSTFIX = new byte[] { 0x00 };
HTable table = new HTable(config, tableName);
Filter filter = new PageFilter(15);
byte[] lastRow = null;
int totalRows = 0;
while (true) {
Scan scan = new Scan();
scan.setFilter(filter);
if(lastRow != null){
//注意这里添加了POSTFIX操作，不然死循环了
byte[] startRow = Bytes.add(lastRow,POSTFIX);
scan.setStartRow(startRow);
}
ResultScanner scanner = table.getScanner(scan);
int localRows = 0;
Result result;
while((result = scanner.next()) != null){
System.out.println(localRows++ + ":" + result);
totalRows ++;
lastRow = result.getRow();
}
scanner.close();
if(localRows == 0) break;
}
System.out.println("total rows:" + totalRows);
}
}
因为hbase的row是字典序列排列的，因此上一次的lastrow需要添加额外的0表示新的开始。另外startKey的那一行是包含在scan里面的。
2.5 KeyOnlyFilter
因为一些应用只想获取data数据，而不是真实的val，可以使用这个过滤器。该过滤器通过
KeyOnlyFilter(boolean lenAsVal)lenAsVal默认为假，表示不把val的长度作为val。否则 val的长度将作为val输出。
final byte[] POSTFIX = new byte[] { 0x00 };
HTable table = new HTable(config, tableName);
Filter filter = new KeyOnlyFilter(false);
byte[] lastRow = null;
int totalRows = 0;
Scan scan = new Scan();
scan.setFilter(filter);
ResultScanner scanner = table.getScanner(scan);
for(Result result: scanner){
for(KeyValue kv: result.raw()){
System.out.println(kv + ":" + Bytes.toString(kv.getValue()));
}
}
2.6 FirstKeyOnlyFilter
在对hbase的表进行扫描的时候，如果指定了FirstKeyOnlyFilter过滤条件则仅仅会返回相同key的第一条kv。
当对hbase中的表进行count，sum操作等集合操作的时候，使用FirstKeyOnlyFilter会带来性能上的提升。
public class KeyOnlyFilterExample { public static void main(String[] args) throws IOException { Configuration config = HBaseConfiguration.create(); config.set("hbase.zookeeper.quorum", "QT-H-0038"); String tableName = "testTable"; String cfName = "colfam1"; final byte[] POSTFIX = new byte[] { 0x00 }; HTable table = new HTable(config, tableName); Filter filter = new FirstKeyOnlyFilter(); byte[] lastRow = null; int totalRows = 0; Scan scan = new Scan(); scan.setFilter(filter); ResultScanner scanner = table.getScanner(scan); for(Result result: scanner){ for(KeyValue kv: result.raw()){ System.out.println(kv + ":" + Bytes.toString(kv.getValue())); } } } }返回的结果是row-5/colfam1:qual1/1354673733503/Put/vlen=4:row1 row1/colfam1:qual1/1354432930568/Put/vlen=4:val1 row2/colfam1:qual2/1354432930568/Put/vlen=4:val3
如果注释掉过滤器的返回的结果是：row-5/colfam1:qual1/1354673733503/Put/vlen=4:row1 row1/colfam1:qual1/1354432930568/Put/vlen=4:val1 row1/colfam1:qual2/1354435819120/Put/vlen=4:val2 row2/colfam1:qual2/1354432930568/Put/vlen=4:val3
2.7 InclusiveStopFilter
因为hbase的scan包含start-row不包含stop-row 如果使用这个过滤器我们可以包含stop-rowHTable table = new HTable(config, tableName); Filter filter = new InclusiveStopFilter(Bytes.toBytes("row1")); Scan scan = new Scan(); scan.setFilter(filter); scan.setStartRow(Bytes.toBytes("row-5")); ResultScanner scanner = table.getScanner(scan); for(Result result: scanner){ System.out.println(result); }
会看到row1包含在结果中了。
2.8 TimestampsFilter
当访问某个Timestamp的新闻的时候，我们需要如下的代码：
TimestampsFilter(List<Long> timestamps)接受的参数的list参数，该Filter也可以和scan.setTimeRange混合使用。例如：
// vv TimestampFilterExample List<Long> ts = new ArrayList<Long>(); ts.add(new Long(5)); ts.add(new Long(10)); // co TimestampFilterExample-1-AddTS Add timestamps to the list. ts.add(new Long(15)); Filter filter = new TimestampsFilter(ts); Scan scan1 = new Scan(); scan1.setFilter(filter); // co TimestampFilterExample-2-AddFilter Add the filter to an otherwise default Scan instance. ResultScanner scanner1 = table.getScanner(scan1); // ^^ TimestampFilterExample System.out.println("Results of scan #1:"); // vv TimestampFilterExample for (Result result : scanner1) { System.out.println(result); } scanner1.close(); Scan scan2 = new Scan(); scan2.setFilter(filter); scan2.setTimeRange(8, 12); // co TimestampFilterExample-3-AddTSRange Also add a time range to verify how it affects the filter ResultScanner scanner2 = table.getScanner(scan2); // ^^ TimestampFilterExample System.out.println("Results of scan #2:"); // vv TimestampFilterExample for (Result result : scanner2) { System.out.println(result); } scanner2.close();
2.9 ColumnCountGetFilter
这个在scan时，无用。
2.10 ColumnPaginationFilter（下来用到的时候在仔细研究下）
* A filter, based on the ColumnCountGetFilter, takes two arguments: limit and offset.
* This filter can be used for row-based indexing, where references to other tables are stored across many columns,
* in order to efficient lookups and paginated results for end users.
Filter filter = new ColumnPaginationFilter(5, 15); Scan scan = new Scan(); scan.setFilter(filter); ResultScanner scanner = table.getScanner(scan); // ^^ ColumnPaginationFilterExample System.out.println("Results of scan:"); // vv ColumnPaginationFilterExample for (Result result : scanner) { System.out.println(result); } scanner.close();
2.11 ColumnPrefixFilter
跟prefxiFilter相似，只是改成了Column，实例如下：// vv ColumnPaginationFilterExample Filter filter = new ColumnPrefixFilter(Bytes.toBytes("qual2")); Scan scan = new Scan(); scan.setFilter(filter); ResultScanner scanner = table.getScanner(scan); // ^^ ColumnPaginationFilterExample System.out.println("Results of scan:"); // vv ColumnPaginationFilterExample for (Result result : scanner) { System.out.println(result); } scanner.close();值scan到与列值与前面匹配的数据。例如qual2匹配qual21。
2.12 RandomRowFilter
随即的返回row的数据，构造函数为RandomRowFilter(float chance)chance取值为0到1.0，如果<0则为空，如果>1则包含所有的行。
3、Decorating Filters
3.1 SkipFilter装饰性过滤器
这个过滤器只作用到keyValueFilter上。KeyValueFilter会返回所有满足条件的row及对应的列。
而加上SkipFilter以后。会发现如果某一行的某一列不符合条件，则这一行全部不返回了。
public static void main(String[] args) throws IOException {
Configuration conf = HBaseConfiguration.create();
HBaseHelper helper = HBaseHelper.getHelper(conf);
helper.dropTable("testtable");
helper.createTable("testtable", "colfam1");
System.out.println("Adding rows to table...");
helper.fillTable("testtable", 1, 30, 5, 2, true, true, "colfam1");
HTable table = new HTable(conf, "testtable");
// vv SkipFilterExample
Filter filter1 = new ValueFilter(CompareFilter.CompareOp.NOT_EQUAL,
new BinaryComparator(Bytes.toBytes("val-0")));
Scan scan = new Scan();
scan.setFilter(filter1); // co SkipFilterExample-1-AddFilter1 Only add the ValueFilter to the first scan.
ResultScanner scanner1 = table.getScanner(scan);
// ^^ SkipFilterExample
System.out.println("Results of scan #1:");
int n = 0;
// vv SkipFilterExample
for (Result result : scanner1) {
for (KeyValue kv : result.raw()) {
System.out.println("KV: " + kv + ", Value: " +
Bytes.toString(kv.getValue()));
// ^^ SkipFilterExample
n++;
// vv SkipFilterExample
}
}
scanner1.close();
Filter filter2 = new SkipFilter(filter1);
scan.setFilter(filter2); // co SkipFilterExample-2-AddFilter2 Add the decorating skip filter for the second scan.
ResultScanner scanner2 = table.getScanner(scan);
// ^^ SkipFilterExample
System.out.println("Total KeyValue count for scan #1: " + n);
n = 0;
System.out.println("Results of scan #2:");
// vv SkipFilterExample
for (Result result : scanner2) {
for (KeyValue kv : result.raw()) {
System.out.println("KV: " + kv + ", Value: " +
Bytes.toString(kv.getValue()));
// ^^ SkipFilterExample
n++;
// vv SkipFilterExample
}
}
scanner2.close();
// ^^ SkipFilterExample
System.out.println("Total KeyValue count for scan #2: " + n);
}
3.2 WhileMatchFilters
相当于while执行，知道不match就break了返回了。