如何在这种特殊情况下模拟cassandra？ [英] How to model cassandra in this particular situations?

问题描述

如果我有下面的表结构，我如何查询

if I have table structure below, how can i query by

"source = 'abc' and created_at >= '2016-01-01 00:00:00'"?

CREATE TABLE articles (
    id text,
    source text,
    created_at timestamp,
    category text,
    channel text,
    last_crawled timestamp,
    text text,
    thumbnail text,
    title text,
    url text,
    PRIMARY KEY (id)
)

我想根据这个来建模我的系统：
http://www.ebaytechblog.com/2012/07/16/cassandra- data-modeling-best-practices-part-1 /

I would like to model my system according to this: http://www.ebaytechblog.com/2012/07/16/cassandra-data-modeling-best-practices-part-1/

编辑：

正在做的是非常类似于你提出的。区别是我们的主键没有方括号来源：
PRIMARY KEY（source，created_at，id）。我们还有另外两个索引：

What we are doing is very similar to what you are proposing. The difference is our primary key doesn't have brackets around source: PRIMARY KEY (source, created_at, id). We also have two other indexes:

CREATE INDEX articles_id_idx ON crawler.articles (id); 
CREATE INDEX articles_url_idx ON crawler.articles (url); 

我们的系统真的很慢。

Our system is really slow like this. What do you suggest?

推荐答案

感谢您的回复。给定表结构

Given the table structure

CREATE TABLE articles (
    id text,
    source text,
    created_at timestamp,
    category text,
    channel text,
    last_crawled timestamp,
    text text,
    thumbnail text,
    title text,
    url text,
    PRIMARY KEY ((source),created_at, id)
)

您可以发出以下查询：

SELECT * FROM articles WHERE source=xxx // Give me all article given the source xxx

SELECT * FROM articles WHERE source=xxx AND created_at > '2016-01-01 00:00:00'; // Give me all articles whose source is xxx and created after 2016-01-01 00:00:00

主键中的夫妇（created_at，id）是为了保证文章的一致性。事实上，在同一已创建时间，可能有两个不同的文章

The couple (created_at,id) in the primary key is here to guarantee article unicity. Indeed, it is possible to have, at the same created_at time, 2 different articles

这篇关于如何在这种特殊情况下模拟cassandra？的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！