diff --git a/db/migrations/20260518210000_pg_observability_pg_stat_statements.sql b/db/migrations/20260518210000_pg_observability_pg_stat_statements.sql
new file mode 100644
index 000000000..eaac0b1ed
--- /dev/null
+++ b/db/migrations/20260518210000_pg_observability_pg_stat_statements.sql
@@ -0,0 +1,22 @@
+-- Grafana SQL dashboards read pg_stat_statements (see tachi-deploy terraform/dashboards/postgres_pg_stat_statements.json).
+--
+-- Applied inside a migration transaction (see tachi-db-migration-engine): cannot use ALTER SYSTEM here.
+-- Instance config: prod uses server-infra/docker-compose.infra.yml (shared_preload_libraries + track);
+-- dev uses Tachi3/docker-compose-dev.yml. After changing preload, recreate / restart Postgres.
+-- Genesis may have created the extension already; IF NOT EXISTS keeps this migration safe.
+
+CREATE EXTENSION IF NOT EXISTS pg_stat_statements;
+
+-- SELECT on pg_stat_* views requires pg_read_all_stats (not covered by SELECT grants on public tables).
+-- Dev/local uses grafana_ro (see dev/postgres-init.sql); prod compose uses grafana_readonly (tachi-deploy postgres-initdb).
+DO $grant_stats$
+BEGIN
+	IF EXISTS (SELECT 1 FROM pg_roles WHERE rolname = 'grafana_ro') THEN
+		EXECUTE 'GRANT pg_read_all_stats TO grafana_ro';
+	END IF;
+
+	IF EXISTS (SELECT 1 FROM pg_roles WHERE rolname = 'grafana_readonly') THEN
+		EXECUTE 'GRANT pg_read_all_stats TO grafana_readonly';
+	END IF;
+END
+$grant_stats$;
diff --git a/db/migrations/20260518221500_score_game_chart_id_idx.sql b/db/migrations/20260518221500_score_game_chart_id_idx.sql
new file mode 100644
index 000000000..557e2de86
--- /dev/null
+++ b/db/migrations/20260518221500_score_game_chart_id_idx.sql
@@ -0,0 +1,2 @@
+-- Speed up per-game score aggregates grouped by chart (GET /games/:game/charts popularity).
+CREATE INDEX IF NOT EXISTS score_game_chart_id_idx ON public.score USING btree (game, chart_id);
diff --git a/dev/postgres-init.sql b/dev/postgres-init.sql
index 669dc5d94..3b3f22b9c 100644
--- a/dev/postgres-init.sql
+++ b/dev/postgres-init.sql
@@ -16,5 +16,6 @@ GRANT CONNECT ON DATABASE tachi_dev TO grafana_ro;
 GRANT USAGE ON SCHEMA public TO grafana_ro;
 GRANT SELECT ON ALL TABLES IN SCHEMA public TO grafana_ro;
 GRANT SELECT ON ALL SEQUENCES IN SCHEMA public TO grafana_ro;
+GRANT pg_read_all_stats TO grafana_ro;
 ALTER DEFAULT PRIVILEGES FOR ROLE tachi IN SCHEMA public GRANT SELECT ON TABLES TO grafana_ro;
 ALTER DEFAULT PRIVILEGES FOR ROLE tachi IN SCHEMA public GRANT SELECT ON SEQUENCES TO grafana_ro;
diff --git a/typescript/server/src/utils/queries/charts.ts b/typescript/server/src/utils/queries/charts.ts
index 667719cdd..d30e1bfea 100644
--- a/typescript/server/src/utils/queries/charts.ts
+++ b/typescript/server/src/utils/queries/charts.ts
@@ -748,7 +748,8 @@ export async function FindUSCChartsByHashSHA1(hash: string): Promise<Array<Chart
  * Returns the N most popular charts for this game + playtype.
  * Popularity is determined by how many rows exist in Postgres `score` for each chart.
  *
- * @param _scoreCollection - ignored; kept for API compatibility with the old Mongo implementation.
+ * Aggregates `score` once per `game` (CTE), then joins `chart`/`song`, so Postgres does not
+ * nested-loop probe `score` per chart (see `score_game_chart_id_idx` on `(game, chart_id)`).
  */
 export async function FindChartsOnPopularity(
 	game: V3Game,
@@ -756,37 +757,49 @@ export async function FindChartsOnPopularity(
 	skip = 0,
 	limit = 100,
 ): Promise<Array<{ __playcount: integer } & ChartDocument>> {
-	let q = DB.selectFrom("chart")
+	if (filters?.chartIDs?.length === 0) {
+		return [];
+	}
+
+	if (filters?.songIDs?.length === 0) {
+		return [];
+	}
+
+	const chartIdFilter = filters?.chartIDs;
+
+	let q = DB.with("score_counts", (db) => {
+		let sq = db
+			.selectFrom("score")
+			.where("score.game", "=", game)
+			.select(["score.chart_id", sql<number>`count(*)::int`.as("playcount")])
+			.groupBy("score.chart_id");
+
+		if (chartIdFilter !== undefined) {
+			sq = sq.where("score.chart_id", "in", chartIdFilter);
+		}
+
+		return sq;
+	})
+		.selectFrom("chart")
 		.innerJoin("song", "song.id", "chart.song_id")
-		.leftJoin("score", "score.chart_id", "chart.id")
+		.leftJoin("score_counts", "score_counts.chart_id", "chart.id")
 		.where("chart.game", "=", game)
 		.where(sql<SqlBool>`(chart.data->>'2dxtraSet') IS NULL`);
 
-	if (filters?.chartIDs) {
-		// empty array - should be no matches, just short circuit
-		if (filters.chartIDs.length === 0) {
-			return [];
-		} else {
-			q = q.where("chart.id", "in", filters.chartIDs);
-		}
+	if (chartIdFilter !== undefined) {
+		q = q.where("chart.id", "in", chartIdFilter);
 	}
 
 	if (filters?.songIDs) {
-		// empty array - should be no matches, just short circuit
-		if (filters.songIDs.length === 0) {
-			return [];
-		} else {
-			q = q.where("song.id", "in", filters.songIDs);
-		}
+		q = q.where("song.id", "in", filters.songIDs);
 	}
 
 	const rows = await q
 		.select([
 			...SELECT_CHART, // format-bearing comment
-			sql<number>`count(score.id)::int`.as("playcount"),
+			sql<number>`coalesce(score_counts.playcount, 0)::int`.as("playcount"),
 		])
-		.groupBy(["chart.id", "song.id"])
-		.orderBy(sql`count(score.id)`, "desc")
+		.orderBy(sql`coalesce(score_counts.playcount, 0)`, "desc")
 		.offset(skip)
 		.limit(limit)
 		.execute();