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-rw-r--r--util/updates/update_2.8.sql34
1 files changed, 34 insertions, 0 deletions
diff --git a/util/updates/update_2.8.sql b/util/updates/update_2.8.sql
index c8bcda38..54367c9b 100644
--- a/util/updates/update_2.8.sql
+++ b/util/updates/update_2.8.sql
@@ -137,3 +137,37 @@ BEGIN
END;
$$ LANGUAGE plpgsql;
+
+
+-- fix calculation of the tags_vn_bayesian.spoiler column
+
+CREATE OR REPLACE FUNCTION tag_vn_calc() RETURNS void AS $$
+BEGIN
+ -- all votes for all tags
+ CREATE OR REPLACE TEMPORARY VIEW tags_vn_all AS
+ SELECT * FROM tags_vn UNION SELECT * FROM tag_vn_childs();
+ -- grouped by (tag, vid, uid), so only one user votes on one parent tag per VN entry
+ CREATE OR REPLACE TEMPORARY VIEW tags_vn_grouped AS
+ SELECT tag, vid, uid, MAX(vote)::real AS vote, AVG(spoiler)::real AS spoiler
+ FROM tags_vn_all GROUP BY tag, vid, uid;
+ -- grouped by (tag, vid) and serialized into a table
+ DROP INDEX IF EXISTS tags_vn_bayesian_tag;
+ TRUNCATE tags_vn_bayesian;
+ INSERT INTO tags_vn_bayesian
+ SELECT tag, vid, COUNT(uid) AS users, AVG(vote)::real AS rating,
+ (CASE WHEN AVG(spoiler) < 0.7 THEN 0 WHEN AVG(spoiler) > 1.3 THEN 2 ELSE 1 END)::smallint AS spoiler
+ FROM tags_vn_grouped
+ GROUP BY tag, vid
+ HAVING AVG(vote) > 0;
+ CREATE INDEX tags_vn_bayesian_tag ON tags_vn_bayesian (tag);
+ -- now perform the bayesian ranking calculation
+ UPDATE tags_vn_bayesian tvs SET rating =
+ ((SELECT AVG(users)::real * AVG(rating)::real FROM tags_vn_bayesian WHERE tag = tvs.tag) + users*rating)
+ / ((SELECT AVG(users)::real FROM tags_vn_bayesian WHERE tag = tvs.tag) + users)::real;
+ -- and update the VN count in the tags table as well
+ UPDATE tags SET c_vns = (SELECT COUNT(*) FROM tags_vn_bayesian WHERE tag = id);
+ RETURN;
+END;
+$$ LANGUAGE plpgsql;
+SELECT tag_vn_calc();
+