1.Java代码实现
import org.apache.hadoop.hbase.client.coprocessor.AggregationClient;
import org.apache.hadoop.hbase.client.coprocessor.LongColumnInterpreter;
import org.apache.hadoop.hbase.coprocessor.AggregateImplementation; /**
* <p>
* 协处理器统计HBase表数据量
* </p>
*
*/
public class HBaseRecordsCounter { /**
* HBase API添加协处理器
* */
public static void addCoprocessor(Configuration conf, String tableName) {
try {
byte[] tableNameBytes = Bytes.toBytes(tableName);
HBaseAdmin hbaseAdmin = new HBaseAdmin(conf);
HTableDescriptor htd = hbaseAdmin.getTableDescriptor(tableNameBytes);
if (!htd.hasCoprocessor(AggregateImplementation.class.getName())) {
hbaseAdmin.disableTable(tableNameBytes);
htd.addCoprocessor(AggregateImplementation.class.getName());
hbaseAdmin.modifyTable(tableNameBytes, htd);
hbaseAdmin.enableTable(tableNameBytes);
}
hbaseAdmin.close();
} catch (MasterNotRunningException e) {
e.printStackTrace();
} catch (ZooKeeperConnectionException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
}
/**
* 统计表数量
*
*/
public static void exeCount(Configuration conf, String tableName, String family) {
try {
// 使用hbase提供的聚合coprocessor
AggregationClient aggregationClient = new AggregationClient(conf);
Scan scan = new Scan();
// 指定扫描列族，唯一值
scan.addFamily(Bytes.toBytes(family));
long start = System.currentTimeMillis();
long rowCount = aggregationClient.rowCount(TableName.valueOf(tableName), new LongColumnInterpreter(), scan);
System.out
.println("Row count: " + rowCount + "; time cost: " + (System.currentTimeMillis() - start) + "ms");
} catch (Throwable e) {
e.printStackTrace();
}
}
public static void main(String[] args) {
String tableName = "test";
Configuration conf = new Configuration();
conf.set("hbase.zookeeper.quorum", "host1,host2,host3");
conf.set("hbase.rootdir", "hdfs://host:8020/hbase");
// 提高RPC通信时长
conf.setLong("hbase.rpc.timeout", 600000);
// 设置Scan缓存
conf.setLong("hbase.client.scanner.caching", 1000);
addCoprocessor(conf, tableName);
exeCount(conf, tableName, "info");
}
}2. 启用协处理器
启用协处理器方法1.
启动全局aggregation，能过操纵所有的表上的数据。通过修改hbase-site.xml这个文件来实现，只需要添加如下代码：
<property>
<name>hbase.coprocessor.user.region.classes</name>
<value>org.apache.hadoop.hbase.coprocessor.AggregateImplementation</value>
</property>
启用协处理器方法2.
hbase shell添加coprocessor:
disable 'member'
alter 'member',METHOD => 'table_att','coprocessor' => 'hdfs://master24:9000/user/hadoop/jars/test.jar|mycoprocessor.SampleCoprocessor|1001|'
enable 'member'
hbase shell 删除coprocessor:
disable 'member'
alter 'member',METHOD => 'table_att_unset',NAME =>'coprocessor$1'
enable 'member'