Question

我已经坚持这个问题好几天了。所以任何帮助都将不胜感激。

我正在尝试将cassandra表复制到hive（以便我可以将其放入hive Metastore然后从Tableau访问它）。蜂巢 - ＆gt; Tableau部分有效，但不是Cassandra到Hive部分。数据未被复制到Hive Metastore。

以下是我采取的步骤：

我按照此项目自述文件中的说明进行操作：https://github.com/tuplejump/cash/tree/master/cassandra-handler

我生成了hive-cassandra - 。 .jar，将其复制并将cassandra-all - .jar，cassandra-thrift - * .jar复制到hive lib文件夹。

然后我开始使用hive并尝试以下操作：

hive> add jar /usr/lib/hive/apache-hive-1.1.0/lib/hive-cassandra-1.2.6.jar;
Added [/usr/lib/hive/apache-hive-1.1.0/lib/hive-cassandra-1.2.6.jar] to class path
Added resources: [/usr/lib/hive/apache-hive-1.1.0/lib/hive-cassandra-1.2.6.jar]
hive> list jars;
/usr/lib/hive/apache-hive-1.1.0/lib/hive-cassandra-1.2.6.jar
hive> create temporary function tmp as 'org.apache.hadoop.hive.cassandra.cql3.CqlStorageHandler'
    > ;
FAILED: Class org.apache.hadoop.hive.cassandra.cql3.CqlStorageHandler not found

我不知道为什么hive看不到CqlStorageHandler ......

谢谢！

Answer 1

您可以考虑的另一种方法是编写一个简单的java程序将数据写入文件，然后将其加载到配置单元。

package com.company.cassandra;

import com.datastax.driver.core.Cluster;
import com.datastax.driver.core.Cluster.Builder;
import com.datastax.driver.core.ResultSet;
import com.datastax.driver.core.ResultSetFuture;
import com.datastax.driver.core.Row;
import com.datastax.driver.core.Session;

public class CassandraExport {

    public static Session session;


    public static void connect(String username, String password, String host, int port, String keyspace) {
        Builder builder =  Cluster.builder().addContactPoint(host);
        builder.withPort(port);
        if (username != null && password != null) {
            builder.withCredentials(username, password);
        }

        Cluster cluster = builder.build();
        session = cluster.connect(keyspace);
    }

    public static void main(String[] args) {
        //Prod
        connect("user", "password", "server", 9042, "keyspace");

        ResultSetFuture future = session.executeAsync("SELECT * FROM table;");
        ResultSet results = future.getUninterruptibly();
        for (Row row : results) {
            //Print the columns in the following order
            String out = row.getString("col1") + "\t" +
                            String.valueOf(row.getInt("col2")) + "\t" +
                            String.valueOf(row.getLong("col3")) + "\t" +
                            String.valueOf(row.getLong("col4"));
            System.out.println(out);
        }

        session.close();
        session.getCluster().close();
    }


}

将输出写入文件，然后加载到配置单元。

hive -e "use schema; load data local inpath '/tmp/cassandra-table' overwrite into table mytable;"

将Cassandra表复制到Hive

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