HBase学习笔记-统计表行数

HBase统计表行数的方式如下：

一、HBase Shell

hbase[b]> count
'tableName', INTERVAL => 1000, CACHE => 1000 
[/b]

INTERVAL为统计的行数间隔，默认为1000，CACHE为统计的数据缓存



二、HBase自带MapReduce表行数统计RowCounter

$HBASE_HOME/bin/hbase org.apache.hadoop.hbase.mapreduce.RowCounter  'tableName'

$HBASE_HOME/bin/hbase org.apache.hadoop.hbase.mapreduce.RowCounter  -Dmapreduce.job.queuename=queue1
'tableName'

三、使用Scan与Filter的方式对表行数进行统计

public static long rowCount(String tableName) {
long rowCount = 0;
try {
HTable table = new HTable(configuration, tableName);
Scan scan = new Scan();
scan.setFilter(new FirstKeyOnlyFilter());
ResultScanner resultScanner = table.getScanner(scan);
for (Result result : resultScanner) {
rowCount += result.size();
}
} catch (IOException e) {
logger.info(e.getMessage(), e);
}
return rowCount;
}

四、使用Coprocessor新特性来对表行数进行统计

public static void addTableCoprocessor(String tableName, String coprocessorClassName) {
try {
admin.disableTable(tableName);
HTableDescriptor htd = admin.getTableDescriptor(Bytes.toBytes(tableName));
htd.addCoprocessor(coprocessorClassName);
admin.modifyTable(Bytes.toBytes(tableName), htd);
admin.enableTable(tableName);
} catch (IOException e) {
logger.info(e.getMessage(), e);
}
}

public static long rowCount(String tableName, String family) {
AggregationClient ac = new AggregationClient(configuration);
Scan scan = new Scan();
scan.addFamily(Bytes.toBytes(family));
long rowCount = 0;
try {
rowCount = ac.rowCount(Bytes.toBytes(tableName), new LongColumnInterpreter(), scan);
} catch (Throwable e) {
logger.info(e.getMessage(), e);
}
return rowCount;
}

@Test
public void testTableRowCount() {
String coprocessorClassName = "org.apache.hadoop.hbase.coprocessor.AggregateImplementation";
HBaseUtils.addTableCoprocessor("user", coprocessorClassName);
long rowCount = HBaseUtils.rowCount("user", "basic");
System.out.println("rowCount: " + rowCount);
}