Question

盲目跟随http://wiki.apache.org/cassandra/CassandraCli，有人可以解释一下吗？

aaron-mac:apache-cassandra-1.0.0 aaron$ bin/cassandra-cli -host localhost -port 9160
Connected to: "Test Cluster" on localhost/9160
Welcome to the Cassandra CLI.

Type 'help;' or '?' for help.
Type 'quit;' or 'exit;' to quit.

[default@unknown] use Keyspace1;
Authenticated to keyspace: Keyspace1

[default@Keyspace1] create column family User with comparator = UTF8Type; 
5ef4bad0-fb2a-11e0-0000-242d50cf1ffd
Waiting for schema agreement...
... schemas agree across the cluster
[default@Keyspace1] set User['jsmith']['first'] = 'John'; 
org.apache.cassandra.db.marshal.MarshalException: cannot parse 'jsmith' as hex bytes
[default@Keyspace1]

Answer 1

在Cassandra CLI中运行任何set命令之前，建议您执行以下操作：

assume <column_family> keys as utf8;
assume <column_family> comparator as utf8;
assume <column_family> validator as utf8;

这将确保您理解的所有内容和列表都将被理解

P.S：这只适用于Cassandra的新人

Answer 2

这是旧版Cassandra。现在，默认情况下，键被视为十六进制字节，因此您需要：

set User[utf8('jsmith')]['first'] = 'John';

或做：

assume User keys as utf8;
set User['jsmith']['first'] = 'John';

或者，正如文档中的说明所说：

注意：从Cassandra 0.8开始，我们需要为列族声明key_validation_class：

update column family User with key_validation_class=UTF8Type;

Answer 3

set User['jsmith'][utf8('first')] = utf8('John');

如果您不确定set命令，可以键入help set;，然后显示完整的文档。

为什么从Cassandra CLI教程剪切和粘贴不起作用？

3 个答案: