Cassandra - 通过主键使用主键列的任意子集搜索

问题描述

是否可以在Cassandra中查找主键与所有主键字段的任意子集匹配的记录？

使用下面的表格，可以找到谁的主键具有特定类型未指定 id 或 size ？

Using the table described below, it is possible to find the records whos's primary key has a particular type and name without specifying an id or size?

CREATE TABLE playlists (
  id      uuid,
  type    text,
  name    text,
  size    int,

  artist text,

  PRIMARY KEY (id, type, name, size)
);

$ b

谢谢！

Thanks!

推荐答案

至少在Cassandra 1.2中是可以的，但是默认情况下是禁用的

At least in Cassandra 1.2 it is possible but it is disabled by default,

如果你尝试这样做：

SELECT * from playlist where type = 'sometype' and name = 'somename';

您会收到此错误：

Bad Request: Cannot execute this query as it might involve data filtering and thus may have unpredictable performance. If you want to execute this query despite the performance unpredictability, use ALLOW FILTERING

this：

SELECT * from playlist where type = 'sometype' and name = 'somename' ALLOW FILTERING;

在您的示例中，Cassandra将允许您使用主键的完整子集从左到右执行查询例如：

In your example Cassandra will allow you to do queries using a complete subset of the primary key from left to right, for example:

SELECT * from playlist where id = 'someid'; (ALLOWED)
SELECT * from playlist where id = 'someid' and type = 'sometype'; (ALLOWED)
SELECT * from playlist where id = 'someid' and type = 'sometype' and name = 'somename'; (ALLOWED)
SELECT * from playlist where id = 'someid' and type = 'sometype' and name = 'somename' and size=somesize; (ALLOWED)

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