How are Reddit and Hacker News ranking algorithms used?

Question

I\'ve been looking at ranking algorithms recently, specifically those used by Reddit and Hacker News. The algorithms themselves are simple enough, but I don\'t quite understand

Answer 1

Reddit uses Pyrex, the sort algorithm is a Python C extension to improve performance.

So, you can do the same in SQL when the record is updated, pex: when is up or down voted.

The pseudocode you must to translate to your SQL engine syntax:

function hot(ups, downs, date){
    score = ups - downs;
    order = log(max(abs(score), 1), 10);
    if (score>0){
        sign = 1;
    } else {
        if (score<0){
            sign = -1;
        } else {
            sign = 0;
        }
    }
    td = date - datetime(1970,1,1);
    seconds = td.days * 86400 + td.seconds + (float(td.microseconds) / 1000000) - 1134028003;

    return round(order + sign * seconds / 45000, 7);
}

So you must to store in the post table the ups, downs, date and the hot function result. And then you can make a sort in the hot column.

You can see the Reddit source code here: http://code.reddit.com/