Use different counts for denominator in scaled rank for posts (#5261)

* Change 'Scaled' sort to use total interactions instead of monthly users

* Misc SQL fixes

* Fix formatting of error message

* Run rustfmt

crates/db_schema/replaceable_schema/utils.sql

@@ -33,16 +33,16 @@ now() - published) < '7 days' THEN
         0.0
     END;
 
-CREATE FUNCTION r.scaled_rank (score numeric, published timestamp with time zone, users_active_month numeric)
+CREATE FUNCTION r.scaled_rank (score numeric, published timestamp with time zone, interactions_month numeric)
     RETURNS double precision
     LANGUAGE sql
     IMMUTABLE PARALLEL SAFE
     -- Add 2 to avoid divide by zero errors
     -- Default for score = 1, active users = 1, and now, is (0.1728 / log(2 + 1)) = 0.3621
-    -- There may need to be a scale factor multiplied to users_active_month, to make
+    -- There may need to be a scale factor multiplied to interactions_month, to make
     -- the log curve less pronounced. This can be tuned in the future.
     RETURN (
-        r.hot_rank (score, published) / log(2 + users_active_month)
+        r.hot_rank (score, published) / log(2 + interactions_month)
 );
 
 -- For tables with `deleted` and `removed` columns, this function determines which rows to include in a count.
@@ -212,6 +212,27 @@ GROUP BY
 END;
 $$;
 
+-- Community aggregate function for adding up total number of interactions
+CREATE OR REPLACE FUNCTION r.community_aggregates_interactions (i text)
+    RETURNS TABLE (
+        count_ bigint,
+        community_id_ integer)
+    LANGUAGE plpgsql
+    AS $$
+BEGIN
+    RETURN query
+    SELECT
+        COALESCE(sum(comments + upvotes + downvotes)::bigint, 0) AS count_,
+        community_id AS community_id_
+    FROM
+        post_aggregates
+    WHERE
+        published >= (CURRENT_TIMESTAMP - i::interval)
+    GROUP BY
+        community_id;
+END;
+$$;
+
 -- Edit site aggregates to include voters and people who have read posts as active users
 CREATE OR REPLACE FUNCTION r.site_aggregates_activity (i text)
     RETURNS integer

crates/db_schema/src/aggregates/post_aggregates.rs

@@ -22,9 +22,10 @@ impl PostAggregates {
 
     // Diesel can't update based on a join, which is necessary for the scaled_rank
     // https://github.com/diesel-rs/diesel/issues/1478
-    // Just select the users_active_month manually for now, since its a single post anyway
-    let users_active_month = community_aggregates::table
-      .select(community_aggregates::users_active_month)
+    // Just select the metrics we need manually, for now, since its a single post anyway
+
+    let interactions_month = community_aggregates::table
+      .select(community_aggregates::interactions_month)
       .inner_join(post::table.on(community_aggregates::community_id.eq(post::community_id)))
       .filter(post::id.eq(post_id))
       .first::<i64>(conn)
@@ -40,7 +41,7 @@ impl PostAggregates {
         post_aggregates::scaled_rank.eq(scaled_rank(
           post_aggregates::score,
           post_aggregates::published,
-          users_active_month,
+          interactions_month,
         )),
       ))
       .get_result::<Self>(conn)

crates/db_schema/src/aggregates/structs.rs

@@ -70,6 +70,9 @@ pub struct CommunityAggregates {
   pub users_active_month: i64,
   /// The number of users with any activity in the last year.
   pub users_active_half_year: i64,
+  /// Number of any interactions over the last month.
+  #[serde(skip)]
+  pub interactions_month: i64,
   #[serde(skip)]
   pub hot_rank: f64,
   pub subscribers_local: i64,

crates/db_schema/src/schema.rs

@@ -252,6 +252,7 @@ diesel::table! {
         users_active_week -> Int8,
         users_active_month -> Int8,
         users_active_half_year -> Int8,
+        interactions_month -> Int8,
         hot_rank -> Float8,
         subscribers_local -> Int8,
         report_count -> Int2,

crates/db_schema/src/utils.rs

@@ -531,7 +531,7 @@ pub mod functions {
 
   define_sql_function! {
     #[sql_name = "r.scaled_rank"]
-    fn scaled_rank(score: BigInt, time: Timestamptz, users_active_month: BigInt) -> Double;
+    fn scaled_rank(score: BigInt, time: Timestamptz, interactions_month: BigInt) -> Double;
   }
 
   define_sql_function! {

crates/routes/src/utils/scheduled_tasks.rs

@@ -256,24 +256,29 @@ async fn process_post_aggregates_ranks_in_batches(conn: &mut AsyncPgConnection)
   while let Some(previous_batch_last_published) = previous_batch_result {
     let updated_rows = sql_query(
       r#"WITH batch AS (SELECT pa.post_id
-               FROM post_aggregates pa
-               WHERE pa.published > $1
-               AND (pa.hot_rank != 0 OR pa.hot_rank_active != 0)
-               ORDER BY pa.published
-               LIMIT $2
-               FOR UPDATE SKIP LOCKED)
-         UPDATE post_aggregates pa
-           SET hot_rank = r.hot_rank(pa.score, pa.published),
-           hot_rank_active = r.hot_rank(pa.score, pa.newest_comment_time_necro),
-           scaled_rank = r.scaled_rank(pa.score, pa.published, ca.users_active_month)
-         FROM batch, community_aggregates ca
-         WHERE pa.post_id = batch.post_id and pa.community_id = ca.community_id RETURNING pa.published;
-    "#,
+           FROM post_aggregates pa
+           WHERE pa.published > $1
+           AND (pa.hot_rank != 0 OR pa.hot_rank_active != 0)
+           ORDER BY pa.published
+           LIMIT $2
+           FOR UPDATE SKIP LOCKED)
+      UPDATE post_aggregates pa
+      SET hot_rank = r.hot_rank(pa.score, pa.published),
+          hot_rank_active = r.hot_rank(pa.score, pa.newest_comment_time_necro),
+          scaled_rank = r.scaled_rank(pa.score, pa.published, ca.interactions_month)
+      FROM batch, community_aggregates ca
+      WHERE pa.post_id = batch.post_id
+      AND pa.community_id = ca.community_id
+      RETURNING pa.published;
+"#,
     )
     .bind::<Timestamptz, _>(previous_batch_last_published)
     .bind::<Integer, _>(update_batch_size)
     .get_results::<HotRanksUpdateResult>(conn)
-    .await.map_err(|e| LemmyErrorType::Unknown(format!("Failed to update {} hot_ranks: {}", "post_aggregates", e)))?;
+    .await
+    .map_err(|e| {
+      LemmyErrorType::Unknown(format!("Failed to update post_aggregates hot_ranks: {}", e))
+    })?;
 
     processed_rows_count += updated_rows.len();
     previous_batch_result = updated_rows.last().map(|row| row.published);
@@ -371,7 +376,7 @@ async fn active_counts(pool: &mut DbPool<'_>) -> LemmyResult<()> {
 
   for (full_form, abbr) in &intervals {
     let update_site_stmt = format!(
-      "update site_aggregates set users_active_{} = (select * from r.site_aggregates_activity('{}')) where site_id = 1",
+      "update site_aggregates set users_active_{} = (select r.site_aggregates_activity('{}')) where site_id = 1",
       abbr, full_form
     );
     sql_query(update_site_stmt).execute(&mut conn).await?;
@@ -380,6 +385,11 @@ async fn active_counts(pool: &mut DbPool<'_>) -> LemmyResult<()> {
     sql_query(update_community_stmt).execute(&mut conn).await?;
   }
 
+  let update_interactions_stmt = "update community_aggregates ca set interactions_month = mv.count_ from r.community_aggregates_interactions('1 month') mv where ca.community_id = mv.community_id_";
+  sql_query(update_interactions_stmt)
+    .execute(&mut conn)
+    .await?;
+
   info!("Done.");
   Ok(())
 }

migrations/2025-01-21-000000_interactions_per_month_schema/down.sql

@@ -0,0 +1,3 @@
+ALTER TABLE community_aggregates
+    DROP COLUMN interactions_month;
+

migrations/2025-01-21-000000_interactions_per_month_schema/up.sql

@@ -0,0 +1,4 @@
+-- Add the interactions_month column
+ALTER TABLE community_aggregates
+    ADD COLUMN interactions_month bigint NOT NULL DEFAULT 0;
+