perf: bound concurrency for approval check reconciliation

backend/.env.example

@@ -25,6 +25,8 @@ GH_TOKEN=
 # Periodic reconciliation safety net (rq-scheduler)
 GITHUB_APPROVAL_CHECK_SCHEDULE_ID=mission-control-approval-check-reconcile
 GITHUB_APPROVAL_CHECK_SCHEDULE_INTERVAL_SECONDS=900
+GITHUB_APPROVAL_CHECK_RECONCILE_CONCURRENCY=3
+GITHUB_APPROVAL_CHECK_RECONCILE_MAX_PR_URLS=500
 
 # Webhook queue / worker
 WEBHOOK_REDIS_URL=redis://localhost:6379/0

backend/app/core/config.py

@@ -60,6 +60,8 @@ class Settings(BaseSettings):
     # Periodic reconciliation safety net for mission-control/approval checks.
     github_approval_check_schedule_id: str = "mission-control-approval-check-reconcile"
     github_approval_check_schedule_interval_seconds: int = 900
+    github_approval_check_reconcile_concurrency: int = Field(default=3, ge=1, le=10)
+    github_approval_check_reconcile_max_pr_urls: int = Field(default=500, ge=1)
 
     # Database lifecycle
     db_auto_migrate: bool = False

backend/app/services/github/mission_control_approval_check.py

@@ -20,6 +20,8 @@ A periodic reconciliation job should call the sync functions as a safety net.
 
 from __future__ import annotations
 
+import asyncio
+
 from dataclasses import dataclass
 from typing import Literal, cast
 from uuid import UUID
@@ -368,10 +370,35 @@ async def reconcile_github_approval_checks_for_board(
         if isinstance(value, str) and value.strip():
             pr_urls.add(value.strip())
 
-    for pr_url in sorted(pr_urls):
-        await sync_github_approval_check_for_pr_url(session, board_id=board_id, pr_url=pr_url)
+    pr_url_list = sorted(pr_urls)
+    max_urls = settings.github_approval_check_reconcile_max_pr_urls
+    if len(pr_url_list) > max_urls:
+        logger.warning(
+            "github.approval_check.reconcile.truncated_pr_urls",
+            extra={"board_id": str(board_id), "count": len(pr_url_list), "max": max_urls},
+        )
+        pr_url_list = pr_url_list[:max_urls]
 
-    return len(pr_urls)
+    sem = asyncio.Semaphore(settings.github_approval_check_reconcile_concurrency)
+
+    async def _run(url: str) -> None:
+        async with sem:
+            await sync_github_approval_check_for_pr_url(
+                session,
+                board_id=board_id,
+                pr_url=url,
+            )
+
+    # Process concurrently but bounded to avoid overwhelming GitHub.
+    results = await asyncio.gather(*[_run(url) for url in pr_url_list], return_exceptions=True)
+    for result in results:
+        if isinstance(result, Exception):
+            logger.exception(
+                "github.approval_check.reconcile.pr_failed",
+                extra={"board_id": str(board_id), "error": str(result)},
+            )
+
+    return len(pr_url_list)
 
 
 async def reconcile_mission_control_approval_checks_for_all_boards() -> int: