26 lines
1 KiB
MySQL
26 lines
1 KiB
MySQL
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-- The hot_rank algorithm currently uses greatest(1, score + 3)
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-- This greatest of 1 incorrect because log10(1) is zero,
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-- so it will push negative-voted comments / posts to the bottom, IE hot_rank = 0
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-- The update_scheduled_ranks will never recalculate them, because it ignores content
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-- with hot_rank = 0
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CREATE OR REPLACE FUNCTION hot_rank (score numeric, published timestamp with time zone)
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RETURNS float
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AS $$
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DECLARE
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hours_diff numeric := EXTRACT(EPOCH FROM (now() - published)) / 3600;
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BEGIN
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-- 24 * 7 = 168, so after a week, it will default to 0.
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IF (hours_diff > 0 AND hours_diff < 168) THEN
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-- Use greatest(2,score), so that the hot_rank will be positive and not ignored.
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RETURN log(greatest (2, score + 2)) / power((hours_diff + 2), 1.8);
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ELSE
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-- if the post is from the future, set hot score to 0. otherwise you can game the post to
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-- always be on top even with only 1 vote by setting it to the future
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RETURN 0.0;
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END IF;
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END;
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$$
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LANGUAGE plpgsql
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IMMUTABLE PARALLEL SAFE;
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