Fixed bug with excluding AVG(vote) < 0 VNs from tag pages

This was *supposed* to be done in
ce6d43aed955effe136f1ce3682828d2d43109cb

1 files changed, 33 insertions, 0 deletions

diff --git a/util/updates/update_2.7.sql b/util/updates/update_2.7.sql
index 0a851ca6..e9061106 100644
--- a/util/updates/update_2.7.sql
+++ b/util/updates/update_2.7.sql
@@ -73,3 +73,36 @@ SELECT tmp_edit_release(r.id)
 
 DROP FUNCTION tmp_edit_release(integer);
 
+
+
+-- Really don't consider VNs with AVG(vote) < 0 on tag pages
+CREATE OR REPLACE FUNCTION tag_vn_calc() RETURNS void AS $$
+BEGIN
+  -- all votes for all tags
+  CREATE OR REPLACE TEMPORARY VIEW tags_vn_all AS
+    SELECT * FROM tags_vn UNION SELECT * FROM tag_vn_childs();
+  -- grouped by (tag, vid, uid), so only one user votes on one parent tag per VN entry
+  CREATE OR REPLACE TEMPORARY VIEW tags_vn_grouped AS
+    SELECT tag, vid, uid, MAX(vote)::real AS vote, COALESCE(AVG(spoiler), 0)::real AS spoiler
+    FROM tags_vn_all GROUP BY tag, vid, uid;
+  -- grouped by (tag, vid) and serialized into a table
+  DROP INDEX IF EXISTS tags_vn_bayesian_tag;
+  TRUNCATE tags_vn_bayesian;
+  INSERT INTO tags_vn_bayesian
+      SELECT tag, vid, COUNT(uid) AS users, AVG(vote)::real AS rating,
+          (CASE WHEN AVG(spoiler) < 0.7 THEN 0 WHEN AVG(spoiler) > 1.3 THEN 2 ELSE 1 END)::smallint AS spoiler
+        FROM tags_vn_grouped
+    GROUP BY tag, vid
+      HAVING AVG(vote) > 0;
+  CREATE INDEX tags_vn_bayesian_tag ON tags_vn_bayesian (tag);
+  -- now perform the bayesian ranking calculation
+  UPDATE tags_vn_bayesian tvs SET rating =
+      ((SELECT AVG(users)::real * AVG(rating)::real FROM tags_vn_bayesian WHERE tag = tvs.tag) + users*rating)
+    / ((SELECT AVG(users)::real FROM tags_vn_bayesian WHERE tag = tvs.tag) + users)::real;
+  -- and update the VN count in the tags table as well
+  UPDATE tags SET c_vns = (SELECT COUNT(*) FROM tags_vn_bayesian WHERE tag = id);
+  RETURN;
+END;
+$$ LANGUAGE plpgsql;
+SELECT tag_vn_calc();
+