I believe what you’re interested in is the topic_links table (in /db/structure.sql)
CREATE TABLE topic_links (
id integer NOT NULL,
topic_id integer NOT NULL,
post_id integer,
user_id integer NOT NULL,
url character varying(500) NOT NULL,
domain character varying(100) NOT NULL,
internal boolean DEFAULT false NOT NULL,
link_topic_id integer,
created_at timestamp without time zone NOT NULL,
updated_at timestamp without time zone NOT NULL,
reflection boolean DEFAULT false,
clicks integer DEFAULT 0 NOT NULL,
link_post_id integer,
title character varying(255),
crawled_at timestamp without time zone,
quote boolean DEFAULT false NOT NULL
);
In the Rails console you could do something like
TopicLink.order("clicks DESC").limit(1)
which gives this from my localhost Discourse
=> [#<TopicLink id: 2, topic_id: 18, post_id: 18, user_id: 2, url: "/faq", domai
n: "localhost:4000", internal: true, link_topic_id: nil, created_at: "2013-01-29
05:25:59", updated_at: "2013-01-29 05:25:59", reflection: false, clicks: 1, lin
k_post_id: nil, title: nil, crawled_at: nil, quote: false>]