From 53c394fd73da04a5e08b78b88f53f11ac091710d Mon Sep 17 00:00:00 2001
From: Eric Allam <eallam@icloud.com>
Date: Tue, 11 Aug 2026 23:18:49 +0100
Subject: [PATCH] perf(webapp): scope declarative schedule sync to the current
 environment

syncDeclarativeSchedules loaded every declarative schedule for the whole project across all environments, then re-fetched deletion candidates it already had in memory. Scope the load to the current environment, drop the redundant re-fetch, and select only the columns the reconcile uses.

Also push projectId onto the schedule-limit count joins so it uses a project-scoped index instead of scanning the full TaskSchedule and RuntimeEnvironment tables.

Follow-up to #4522, which batched the delete side.
---
 .../scope-declarative-schedule-sync.md        |  6 ++++
 .../app/v3/services/checkSchedule.server.ts   |  2 ++
 .../services/createBackgroundWorker.server.ts | 29 +++++++++++--------
 3 files changed, 25 insertions(+), 12 deletions(-)
 create mode 100644 .server-changes/scope-declarative-schedule-sync.md

diff --git a/.server-changes/scope-declarative-schedule-sync.md b/.server-changes/scope-declarative-schedule-sync.md
new file mode 100644
index 00000000000..feb4050d3ee
--- /dev/null
+++ b/.server-changes/scope-declarative-schedule-sync.md
@@ -0,0 +1,6 @@
+---
+area: webapp
+type: improvement
+---
+
+Make background worker registration cheaper for projects with many scheduled tasks by scoping declarative schedule reconciliation to the current environment and dropping redundant schedule lookups.
diff --git a/apps/webapp/app/v3/services/checkSchedule.server.ts b/apps/webapp/app/v3/services/checkSchedule.server.ts
index 0115c742069..bc28ee9c357 100644
--- a/apps/webapp/app/v3/services/checkSchedule.server.ts
+++ b/apps/webapp/app/v3/services/checkSchedule.server.ts
@@ -131,12 +131,14 @@ export class CheckScheduleService extends BaseService {
         projectId,
         active: true,
         environment: {
+          projectId,
           type: {
             not: "DEVELOPMENT",
           },
           archivedAt: null,
         },
         taskSchedule: {
+          projectId,
           active: true,
         },
       },
diff --git a/apps/webapp/app/v3/services/createBackgroundWorker.server.ts b/apps/webapp/app/v3/services/createBackgroundWorker.server.ts
index 25913230b26..dc5c79129ac 100644
--- a/apps/webapp/app/v3/services/createBackgroundWorker.server.ts
+++ b/apps/webapp/app/v3/services/createBackgroundWorker.server.ts
@@ -655,9 +655,21 @@ export async function syncDeclarativeSchedules(
     where: {
       type: "DECLARATIVE",
       projectId: environment.projectId,
+      instances: {
+        some: {
+          environmentId: environment.id,
+        },
+      },
     },
-    include: {
-      instances: true,
+    select: {
+      id: true,
+      friendlyId: true,
+      taskIdentifier: true,
+      instances: {
+        select: {
+          environmentId: true,
+        },
+      },
     },
   });
 
@@ -764,16 +776,9 @@ export async function syncDeclarativeSchedules(
 
   //Delete instances for this environment
   //Delete schedules that have no instances left
-  const potentiallyDeletableSchedules = await prisma.taskSchedule.findMany({
-    where: {
-      id: {
-        in: boundedIn(Array.from(missingSchedules)),
-      },
-    },
-    include: {
-      instances: true,
-    },
-  });
+  const potentiallyDeletableSchedules = existingDeclarativeSchedules.filter((schedule) =>
+    missingSchedules.has(schedule.id)
+  );
 
   const scheduleIdsToDelete: string[] = [];
   const scheduleIdsToDetachFromEnvironment: string[] = [];