HBase行突变替换行的所有列

Question

我有一个HBase(v0.94.7)表，其中只有一个列族，并且随着时间的推移，列会添加到表中。这些列以它们创建的时间戳命名，因此除非查询该行，否则我不知道它有哪些列。

现在给定一行，我想原子式地移除这个列族的所有现有列，并添加一组新的列和值。

所以我想到使用HBase的RowMutations：

RowMutations mutations = new RowMutations(row);

//delete the column family
Delete delete = new Delete(row);
delete.deleteFamily(cf);

//add new columns
Put put = new Put(row);
put.add(cf, col1, v1);
put.add(cf, col2, v2);

//delete column family and add new columns to same family
mutations.add(delete);
mutations.add(put);

table.mutateRow(mutations);

但这段代码最终只会删除列族，而不会添加新列。这种行为是意料之中的吗？

如果是这样，那么我如何实现我的目标，用一组新的列原子地替换列族的所有列呢？

下面是一个相同的测试用例：

import junit.framework.Assert;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.hbase.HBaseConfiguration;
import org.apache.hadoop.hbase.HColumnDescriptor;
import org.apache.hadoop.hbase.HTableDescriptor;
import org.apache.hadoop.hbase.TableExistsException;
import org.apache.hadoop.hbase.client.*;
import org.apache.hadoop.hbase.util.Bytes;
import org.junit.Before;
import org.junit.BeforeClass;
import org.junit.Test;

import java.util.NavigableMap;

public class TestHBaseRowMutations {
    static String tableName = "nnn";
    static byte[] cf1 = Bytes.toBytes("cf1");
    static byte[] row = Bytes.toBytes("r1");
    static HTablePool hTablePool;

    @BeforeClass
    public static void beforeClass() throws Exception {
        Configuration config = HBaseConfiguration.create();
        hTablePool = new HTablePool(config, Integer.MAX_VALUE);
        HBaseAdmin admin = new HBaseAdmin(config);
        HTableDescriptor tableDescriptor = new HTableDescriptor(tableName);
        tableDescriptor.addFamily(new HColumnDescriptor(cf1));
        try {
            admin.createTable(tableDescriptor);
        } catch (TableExistsException ignored){}
    }

    @Before
    public void before() throws Exception {
        HTableInterface table = hTablePool.getTable(tableName);
        try {
            Delete delete = new Delete(row);
            table.delete(delete);
            System.out.println("deleted old row");

            Put put = new Put(row);
            put.add(cf1, Bytes.toBytes("c1"), Bytes.toBytes("v1"));
            put.add(cf1, Bytes.toBytes("c11"), Bytes.toBytes("v11"));
            table.put(put);
            System.out.println("Created row with seed data");
        } finally {
            table.close();
        }
    }


    @Test
    public void testColumnFamilyDeleteRM() throws Exception {
        HTableInterface table = hTablePool.getTable(tableName);
        try {
            RowMutations rm =new RowMutations(row);

            //delete column family cf1
            Delete delete = new Delete(row);
            delete.deleteFamily(cf1);
            rm.add(delete);
            System.out.println("Added delete of cf1 column family to row mutation");

            //add new columns to same column family cf1
            Put put = new Put(row);
            put.add(cf1, Bytes.toBytes("c1"), Bytes.toBytes("new_v1"));
            put.add(cf1, Bytes.toBytes("c11"), Bytes.toBytes("new_v11"));
            rm.add(put);
            System.out.println("Added puts of cf1 column family to row mutation");

            //atomic mutate the row
            table.mutateRow(rm);
            System.out.println("Mutated row");

            //now read the column family cf1 back
            Result result = table.get(new Get(row));
            NavigableMap<byte[], byte[]> familyMap = result.getFamilyMap(cf1);

            //column family cf1 should have 2 columns because of the Put above
            //------Following assert fails as cf1 does not exist anymore, why does cf1 not exist anymore?-------
            Assert.assertNotNull(familyMap);
            Assert.assertEquals(2, familyMap.size());
        } finally {
            table.close();
        }
    }
}

Answer 1

在HBase用户论坛上发布了同样的问题，结果发现这是HBase的一个bug。

预期的行为是，如果RowMutation对某个column-family/column/row有一个Delete，然后对同一个column-family/column/row有一个Put，那么也应该遵守Put（但目前不是这样）。

HBase用户组对此的讨论:http://apache-hbase.679495.n3.nabble.com/using-rowmutations-to-replace-all-columns-of-a-row-td4045247.html

同样的HBase JIRA：https://issues.apache.org/JIRA/browse/HBase-8626，它也提供补丁。