From e8e09eed46e313cefee64b1165912b60d1bf81b7 Mon Sep 17 00:00:00 2001
From: Jinwoo Hong <73622457+Jinwoo-H@users.noreply.github.com>
Date: Wed, 30 Sep 2026 02:59:48 -0400
Subject: [PATCH] fix(push): size the claim-attempt budget from the drain count
 (#24040)

* fix(push): size the claim-attempt budget from the drain count

With twelve drains, up to eleven peers can hold device heads, so a
four-attempt claim budget can run out while claimable rows remain and the
drain exits idle for a tick. Move the drain count into one module and derive
the attempt budget from it.

Claude-Session: ced32ebb-7155-4413-adad-1eccd14c2010

* style(push): keep the worker and store in repo formatting

Claude-Session: ced32ebb-7155-4413-adad-1eccd14c2010

* style(push): drop the stray semicolon in the concurrency constant

Claude-Session: ced32ebb-7155-4413-adad-1eccd14c2010
---
 cloud/apps/push/src/durable-push-store.ts      | 5 +++--
 cloud/apps/push/src/durable-push-worker.ts     | 8 +++-----
 cloud/apps/push/src/push-worker-concurrency.ts | 3 +++
 3 files changed, 9 insertions(+), 7 deletions(-)
 create mode 100644 cloud/apps/push/src/push-worker-concurrency.ts

diff --git a/cloud/apps/push/src/durable-push-store.ts b/cloud/apps/push/src/durable-push-store.ts
index 02d26f20b3e..b84ebb17893 100644
--- a/cloud/apps/push/src/durable-push-store.ts
+++ b/cloud/apps/push/src/durable-push-store.ts
@@ -2,13 +2,14 @@ import { isDismissedAlert, reconcileQueuedDismissal } from './push-queued-dismis
 import { parsePushDeliveryPayload } from './push-delivery-payload.js'
 import { createHash, randomUUID } from 'node:crypto'
 import { PUSH_LIMITS, type PushNotification } from '@orca-cloud/push-contract'
+import { WORKER_DRAINS } from './push-worker-concurrency.js'
 import type { PushDatabase, SqlRow } from './push-database.js'
 
 const RETENTION_MS = 24 * 60 * 60_000
 // accept() caps expires_at at due_at + TTL, so older due_at is expired: scans skip an unpruned backlog.
 const TTL_MS = PUSH_LIMITS.notificationTtlSeconds * 1000
-// Covers one claimer per worker drain skipping a device another drain holds.
-const CLAIM_CANDIDATE_ATTEMPTS = 4
+// One winner plus every other drain holding a device head, so a full set of peers cannot exhaust it.
+const CLAIM_CANDIDATE_ATTEMPTS = WORKER_DRAINS
 export const PRUNE_BATCH_ROWS = 2_000
 export const PRUNE_MAX_BATCHES = 50
 export const DELIVERY_LEASE_MS = 30_000
diff --git a/cloud/apps/push/src/durable-push-worker.ts b/cloud/apps/push/src/durable-push-worker.ts
index 2a1a22f7a33..f5bcc20fc2c 100644
--- a/cloud/apps/push/src/durable-push-worker.ts
+++ b/cloud/apps/push/src/durable-push-worker.ts
@@ -1,10 +1,7 @@
 import { buildPushDelivery } from './push-delivery-message.js'
 import type { PushDispatcher } from './push-dispatcher.js'
 import type { DurablePushStore } from './durable-push-store.js'
-
-// Four drains capped delivery near 30/s at ~120 ms per item, below the 2026-09 inflow; each drain
-// holds one delivery in flight, so this is the worker's concurrency, not its DB draw.
-const WORKER_DRAINS = 12
+import { WORKER_DRAINS } from './push-worker-concurrency.js'
 
 export class DurablePushWorker {
   private timer?: NodeJS.Timeout
@@ -33,7 +30,8 @@ export class DurablePushWorker {
       return
     }
     if (this.stopped) return
-    const pending = Promise.allSettled(Array.from({ length: WORKER_DRAINS }, () => this.drain())).then(
+    const drains = Array.from({ length: WORKER_DRAINS }, () => this.drain())
+    const pending = Promise.allSettled(drains).then(
       (results) => {
         const failure = results.find((result) => result.status === 'rejected')
         if (failure?.status === 'rejected') throw failure.reason
diff --git a/cloud/apps/push/src/push-worker-concurrency.ts b/cloud/apps/push/src/push-worker-concurrency.ts
new file mode 100644
index 00000000000..daec5659d21
--- /dev/null
+++ b/cloud/apps/push/src/push-worker-concurrency.ts
@@ -0,0 +1,3 @@
+// Twelve drains lift the ~30/s ceiling four drains hit at ~120 ms per item; each drain holds one
+// delivery in flight, so this is the worker's concurrency, not its database draw.
+export const WORKER_DRAINS = 12