Fetch match-history participants in one query per page

server/packages/tavolo-platform/src/tavolo/platform/routes/stats.py

@@ -8,7 +8,9 @@ verbatim through the ``result`` JSON column.
 """
 from __future__ import annotations
 
+from collections import defaultdict
 from typing import TYPE_CHECKING, Any, Dict, List, Optional, Tuple
+from uuid import UUID
 
 from kaya.core import HttpContext, KayaApp
 from kaya.openapi import operation
@@ -48,8 +50,9 @@ def _parse_game_type(
     return game_type, None
 
 
-async def _serialize_match(match: Match, viewer: str) -> Dict[str, Any]:
+def _serialize_match(
-    participants = await MatchPlayer.filter(match_id=match.id).order_by("seat")
+    match: Match, viewer: str, participants: List[MatchPlayer]
+) -> Dict[str, Any]:
     return {
         "id": str(match.id),
         "game_type": match.game_type,
@@ -109,7 +112,21 @@ def register(app: KayaApp, platform: "Platform") -> None:
         matches, next_cursor = await paginate(
             queryset, [("finished_at", "DESC"), ("id", "ASC")], cursor
         )
-        results = [await _serialize_match(m, user.sub) for m in matches]
+        # One participants query for the whole page instead of one per
+        # match; the grouping keeps each match's players seat-ordered.
+        by_match: Dict[UUID, List[MatchPlayer]] = defaultdict(list)
+        if matches:
+            participants = (
+                await MatchPlayer.filter(match_id__in=[m.id for m in matches])
+                .order_by("match_id", "seat")
+            )
+            for player in participants:
+                # Tortoise sets the FK's raw id on instances but does not
+                # declare it on the model class, hence the getattr.
+                by_match[getattr(player, "match_id")].append(player)
+        results = [
+            _serialize_match(m, user.sub, by_match.get(m.id, [])) for m in matches
+        ]
         await send_json(ctx, 200, {"results": results, "next_cursor": next_cursor})
 
     @app.GET("/api/leaderboard")

server/packages/tavolo-platform/tests/test_stats.py

@@ -4,6 +4,7 @@ from __future__ import annotations
 import unittest
 import uuid
 from datetime import datetime, timezone
+from unittest import mock
 
 from httpx import ASGITransport, AsyncClient
 
@@ -197,6 +198,28 @@ class StatsRouteTest(unittest.TestCase):
                 second.json()["results"][0]["id"],
             )
 
+    @async_test
+    async def test_my_matches_fetches_participants_in_one_query(self) -> None:
+        app, platform, tortoise_mixin = make_platform()
+        await _seed_two_matches(tortoise_mixin)
+        transport = ASGITransport(app=app)
+        with mock.patch.object(
+            MatchPlayer, "filter", wraps=MatchPlayer.filter
+        ) as spy:
+            async with AsyncClient(
+                transport=transport, base_url="http://127.0.0.1"
+            ) as client:
+                with oidc_user(platform.oidc, "alice"):
+                    response = await client.get("/api/me/matches")
+        self.assertEqual(200, response.status_code)
+        # One query for all matches, not one per match row.
+        self.assertEqual(1, spy.call_count)
+        results = response.json()["results"]
+        self.assertEqual(2, len(results))
+        for result in results:
+            seats = [player["seat"] for player in result["players"]]
+            self.assertEqual([0, 1], seats)
+
     @async_test
     async def test_my_matches_requires_auth(self) -> None:
         app, _, _ = make_platform()