带时间戳的HBase Put不起作用

Question

我编写了一个简单的测试程序来插入一行。与普通HBase Put示例程序的唯一不同之处在于，Put实例及其KeyValue实例是用时间戳创建的。

预期的行为是插入行。但是，在我的HBase环境中，没有插入行。

下面是我的测试程序。

import java.io.*;
import java.util.*;
import org.apache.hadoop.conf.*;
import org.apache.hadoop.hbase.*;
import org.apache.hadoop.hbase.client.*;
import org.apache.hadoop.hbase.util.*;

public class Test
{
    // Names of table, family, qualifier and row ID.
    private static final byte[] TABLE     = Bytes.toBytes("test-table");
    private static final byte[] FAMILY    = Bytes.toBytes("test-family");
    private static final byte[] QUALIFIER = Bytes.toBytes("test-qualifier");
    private static final byte[] ROWID     = Bytes.toBytes("test-rowid");

    /**
     * The entry point of this program.
     *
     * <p>
     * This program assumes that there already exists an HBase
     * table named "test-table" with a column family named
     * "test-family". To create an HBase table satisfying these
     * conditions, type the following at the hbase shell prompt.
     * </p>
     *
     * <pre>
     * hbase&gt; create 'test-table', 'test-family'
     * </pre>
     *
     * <p>
     * This program inserts a row whose row ID is "test-rowid"
     * with a column named "test-family:test-qualifier". The
     * value of the column is the string expression of
     * <code>new Date()</code>.
     * </p>
     */
    public static void main(String[] args) throws Exception
    {
        // Get the table.
        Configuration conf = HBaseConfiguration.create();
        HTable table = new HTable(conf, TABLE);

        // Prepare data to put.
        byte[] value = Bytes.toBytes(new Date().toString());
        Put put = new Put(ROWID);
        put.add(FAMILY, QUALIFIER, value);

        // Clone Put with a timestamp.
        put = clone(put, 10);

        // Put the data.
        table.put(put);

        // Read back the data.
        Get get = new Get(ROWID);
        Result result = table.get(get);

        // Dump the read data.
        System.out.println("DATA = " + result.toString());
    }

    /**
     * Clone the given Put instance with the given timestamp.
     */
    private static Put clone(Put a, long timestamp) throws IOException
    {
        // Create a Put instance with the specified timestamp.
        Put b = new Put(a.getRow(), timestamp);

        Map<byte[], List<KeyValue>> kvs = a.getFamilyMap();

        // Copy KeyValue's from the source Put (a) to
        // the cloned Put (b). Note the given timestamp
        // is used for each new KeyValue instance.
        for (List<KeyValue> kvl : kvs.values())
        {
            for (KeyValue kv : kvl)
            {
                b.add(new KeyValue(
                    kv.getRow(),
                    kv.getFamily(),
                    kv.getQualifier(),
                    timestamp,
                    kv.getValue()));
            }
        }

        return b;
    }
}

该程序生成的控制台输出如下所示。

DATA = keyvalues=NONE

而hbase shell中的“scan”表示“0行（s）”。

hbase(main):011:0> scan 'test-table'
ROW                                              COLUMN+CELL
0 row(s) in 0.0080 seconds

        // Clone Put with a timestamp.
        //put = clone(put, 10);

DATA = keyvalues={test-rowid/test-family:test-qualifier/1344594210281/Put/vlen=28}

hbase(main):012:0> scan 'test-table'
ROW                                              COLUMN+CELL
 test-rowid                                      column=test-family:test-qualifier, timestamp=1344594210281, value=Fri Aug 10 19:23:30 JST 2012
1 row(s) in 0.0110 seconds

Answer 1

时间戳列族和列名构成组合键。这里的时间戳是UNIX时间戳。