refactor: optimize MongoDB queries in findMentionedMessages and findStarredMessages with Promise.all

[CodeUltr0n]

Proposed changes

Optimizes MongoDB query performance in two Activity Hub-related service functions by replacing sequential database lookups with concurrent Promise.all calls.

Affected Functions

File: apps/meteor/app/api/server/lib/messages.ts

1. findMentionedMessages (lines 7–44)
2. findStarredMessages (lines 46–83)

The Problem

Both functions were performing two independent MongoDB queries sequentially, even though neither result depends on the other:

// Before — sequential (slower)
const room = await Rooms.findOneById(roomId);
const user = await Users.findOneById(uid, { projection: { username: 1 } });

// After — concurrent (faster)
const [room, user] = await Promise.all([
  Rooms.findOneById(roomId),
  Users.findOneById<Pick<IUser, 'username'>>(uid, { projection: { username: 1 } }),
]);

Performance Impact

For a typical deployment with 50ms DB latency:

• Before: ~100ms (50ms + 50ms sequential)
• After: ~50ms (both run simultaneously)
• Result: ~50% faster response time for mentions and starred messages endpoints

---

Issue(s)

Related to Activity Hub project (#39577). Closes #39606.

This optimizes the backend service functions used by:

• GET /v1/chat.getMentionedMessages
• GET /v1/chat.getStarredMessages

These endpoints power the Mentions and Starred Messages tabs in the Activity Hub UI.

---

Steps to test or reproduce

1. Open any room's Mentions panel or Starred Messages panel
2. Observe faster panel load times (reduced API response time)
3. Confirm no visual or behavioral changes

Performance improvement can be verified via:

• Server-side query timing logs
• Network tab showing faster API response times

---

Further comments

• Impact: Pure performance improvement — zero behavior changes
• Scope: Affects 2 service functions used by Activity Hub endpoints
• Pattern: Consistent with the Promise.all optimization applied in fix: replace sequential awaits with Promise.all in thread endpoints #39580 for thread endpoints
• Changeset: Added appropriate changeset file

Summary by CodeRabbit

• Refactor
  • Performance improvements across chat: thread listing, synchronization, message retrieval, and search (including mentions and starred messages) now fetch related data in parallel, yielding faster response times and snappier UI behavior.

[dionisio-bot]

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[changeset-bot]

🦋 Changeset detected

Latest commit: 2383357

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 41 packages

Name	Type
@rocket.chat/meteor	Patch
@rocket.chat/core-typings	Patch
@rocket.chat/rest-typings	Patch
@rocket.chat/uikit-playground	Patch
@rocket.chat/api-client	Patch
@rocket.chat/apps	Patch
@rocket.chat/core-services	Patch
@rocket.chat/cron	Patch
@rocket.chat/ddp-client	Patch
@rocket.chat/fuselage-ui-kit	Patch
@rocket.chat/gazzodown	Patch
@rocket.chat/http-router	Patch
@rocket.chat/livechat	Patch
@rocket.chat/model-typings	Patch
@rocket.chat/ui-avatar	Patch
@rocket.chat/ui-client	Patch
@rocket.chat/ui-contexts	Patch
@rocket.chat/ui-voip	Patch
@rocket.chat/web-ui-registration	Patch
@rocket.chat/account-service	Patch
@rocket.chat/authorization-service	Patch
@rocket.chat/ddp-streamer	Patch
@rocket.chat/omnichannel-transcript	Patch
@rocket.chat/presence-service	Patch
@rocket.chat/queue-worker	Patch
@rocket.chat/abac	Patch
@rocket.chat/federation-matrix	Patch
@rocket.chat/license	Patch
@rocket.chat/media-calls	Patch
@rocket.chat/omnichannel-services	Patch
@rocket.chat/pdf-worker	Patch
@rocket.chat/presence	Patch
rocketchat-services	Patch
@rocket.chat/models	Patch
@rocket.chat/network-broker	Patch
@rocket.chat/omni-core-ee	Patch
@rocket.chat/mock-providers	Patch
@rocket.chat/ui-video-conf	Patch
@rocket.chat/instance-status	Patch
@rocket.chat/omni-core	Patch
@rocket.chat/server-fetch	Patch

Not sure what this means? Click here to learn what changesets are.

Click here if you're a maintainer who wants to add another changeset to this PR

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: Organization UI

Review profile: CHILL

Plan: Pro

Run ID: c47d4582-e890-4a38-8792-df7cae918e8e

📥 Commits

Reviewing files that changed from the base of the PR and between 5c323c2 and 2383357.

📒 Files selected for processing (1)

• .changeset/perf-thread-endpoints-promise-all.md

🚧 Files skipped from review as they are similar to previous changes (1)

• .changeset/perf-thread-endpoints-promise-all.md

---

Walkthrough

Replaces sequential awaits for independent room and user lookups with concurrent Promise.all calls across message and chat thread endpoints; adds a changeset entry and removes a stray TODO comment.

Changes

Cohort / File(s)	Summary
Promise.all optimization — message endpoints apps/meteor/app/api/server/lib/messages.ts	Parallelized Rooms.findOneById and Users.findOneById with Promise.all in findMentionedMessages and findStarredMessages (removed sequential user fetch).
Promise.all optimization — chat endpoints apps/meteor/app/api/server/v1/chat.ts	Replaced sequential awaits with Promise.all for user and room lookups across chat.getThreadsList, chat.syncThreadsList, chat.getThreadMessages, and chat.syncThreadMessages.
Changelog / minor cleanup .changeset/perf-thread-endpoints-promise-all.md, apps/meteor/client/views/room/contextualBar/Info/RoomInfo/ABAC/RoomInfoABACSection.tsx	Added changeset documenting the optimization; removed a TODO comment in RoomInfoABACSection (no runtime/API changes).

Sequence Diagram(s)

mermaid
sequenceDiagram
participant Client
participant Server
participant DB
Client->>Server: Request (mentions / starred / threads)
Server->>DB: Rooms.findOneById(roomId)
Server->>DB: Users.findOneById(uid, {username})
Note right of DB: Both queries run concurrently via Promise.all
DB-->>Server: room, user
Server->>Server: validate room access & user existence
Server-->>Client: Response (messages)

Estimated code review effort

🎯 2 (Simple) | ⏱️ ~12 minutes

🚥 Pre-merge checks | ✅ 3 | ❌ 2

❌ Failed checks (1 warning, 1 inconclusive)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 0.00% which is insufficient. The required threshold is 80.00%.	Write docstrings for the functions missing them to satisfy the coverage threshold.
Out of Scope Changes check	❓ Inconclusive	Most changes align with the optimization scope, but the PR includes unrelated modifications: thread endpoints in chat.ts and TODO comment removal in RoomInfoABACSection.tsx appear outside issue #39606's stated scope.	Clarify whether chat.ts thread endpoint optimizations and RoomInfoABACSection.tsx changes are part of a related performance initiative or should be split into separate PRs.

✅ Passed checks (3 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title accurately summarizes the main change: optimizing MongoDB queries in two specific functions using Promise.all for concurrent execution.
Linked Issues check	✅ Passed	The PR fully addresses all coding requirements from issue #39606: both findMentionedMessages and findStarredMessages now use Promise.all to concurrently fetch room and user data.

_{✏️ Tip: You can configure your own custom pre-merge checks in the settings.}

📝 Coding Plan

• Generate coding plan for human review comments

---

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[cubic-dev-ai]

1 issue found across 4 files

Prompt for AI agents (unresolved issues)

Check if these issues are valid — if so, understand the root cause of each and fix them. If appropriate, use sub-agents to investigate and fix each issue separately.


<file name=".changeset/perf-thread-endpoints-promise-all.md">

<violation number="1" location=".changeset/perf-thread-endpoints-promise-all.md:5">
P2: Changeset description is inconsistent with the PR’s actual scope, so release notes would report the wrong endpoints being optimized.</violation>
</file>

_{Reply with feedback, questions, or to request a fix. Tag @cubic-dev-ai to re-run a review.}

[cubic-dev-ai]

P2: Changeset description is inconsistent with the PR’s actual scope, so release notes would report the wrong endpoints being optimized.

Prompt for AI agents

Check if this issue is valid — if so, understand the root cause and fix it. At .changeset/perf-thread-endpoints-promise-all.md, line 5:

<comment>Changeset description is inconsistent with the PR’s actual scope, so release notes would report the wrong endpoints being optimized.</comment>

<file context>
@@ -0,0 +1,5 @@
+'@rocket.chat/meteor': patch
+---
+
+Improve performance of thread-related chat endpoints by replacing sequential `await` calls with concurrent `Promise.all` for independent `Users` and `Rooms` database lookups. Affected endpoints: `chat.getThreadsList`, `chat.syncThreadsList`, `chat.getThreadMessages`, `chat.syncThreadMessages`.
</file context>