WIP: Add trending vote sort to topic voting plugin#38839
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WIP: Add trending vote sort to topic voting plugin#38839
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The existing "Votes" sort orders topics by all-time vote count, which causes old, resolved topics to permanently dominate the list. Communities using the voting plugin have been asking for a way to surface topics gaining traction *recently* since 2016. This adds a "Trending" sort that uses a time-decay formula where each vote contributes `1 / (age_in_hours + 2)` to the topic's trending score. Recent votes naturally weigh more — a vote cast 1 hour ago scores ~0.33 while a vote cast 30 days ago scores ~0.001. No windows, thresholds, or scheduled jobs needed. The sort is available via `?order=votes-trending` on topic lists and through the new "Trending" navigation tab in voting-enabled categories. It also works with the TopicsFilter query string (`order:votes-trending`). All-time vote count is used as a tiebreaker, then bumped_at. A composite index on `(topic_id, created_at)` is added to `topic_voting_votes` to keep the correlated subquery fast. The JS initializer is also refactored to reduce duplication across the three voting navigation bar items. Ref - t/180396
Discourse enforces a safety check that prevents creating indexes concurrently without first dropping any existing (potentially invalid) index. This follows the Postgres recommendation that if a concurrent index build fails, it leaves behind an invalid index that should be dropped before retrying. Replace the single `add_index` with `if_not_exists` by an explicit `remove_index` with `if_exists` followed by `add_index` with `algorithm: :concurrently`, which satisfies the safety check.
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The existing "Votes" sort orders topics by all-time vote count, which causes old, resolved topics to permanently dominate the list. Communities using the voting plugin have been asking for a way to surface topics gaining traction recently since 2016.
This adds a "Trending" sort that uses a time-decay formula where each vote contributes
1 / (age_in_hours + 2)to the topic's trending score. Recent votes naturally weigh more — a vote cast 1 hour ago scores ~0.33 while a vote cast 30 days ago scores ~0.001. No windows, thresholds, or scheduled jobs needed.The sort is available via
?order=votes-trendingon topic lists and through the new "Trending" navigation tab in voting-enabled categories. It also works with the TopicsFilter query string (order:votes-trending). All-time vote count is used as a tiebreaker, then bumped_at.A composite index on
(topic_id, created_at)is added totopic_voting_votesto keep the correlated subquery fast.The JS initializer is also refactored to reduce duplication across the three voting navigation bar items.
Ref - t/180396