wekan/docs/DeveloperDocs/Optimized-2025-02-07/Performance_optimization_analysis.md

UI Performance Optimization Analysis: Replace Meteor.call with Pub/Sub

Current Issues Identified

The codebase uses several patterns where Meteor.call() could be replaced with pub/sub subscriptions for faster UI updates:

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CRITICAL OPPORTUNITIES (High Impact)

1. cron.getMigrationProgress - Polling Every 2 Seconds

Location: imports/cronMigrationClient.js lines 26-53, called every 2 seconds via setInterval Current Issue:

• Polls for progress data every 2000ms even when nothing is changing
• Adds server load with repeated RPC calls
• Client must wait for response before updating

Recommended Solution:

• Already partially implemented! Migration status is published via cronMigrationStatus publication
• Keep existing pub/sub for status updates (statusMessage, status field)
• Still use polling for getMigrationProgress() for non-status data (migration steps list, ETA calculation)

Implementation Status: ✅ Already in place

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2. AccountSettings Helper Methods - Used in Profile Popup

Location: client/components/users/userHeader.js lines 173, 182, 191 Current Methods:

Meteor.call('AccountSettings.allowEmailChange', (_, result) => {...})
Meteor.call('AccountSettings.allowUserNameChange', (_, result) => {...})
Meteor.call('AccountSettings.allowUserDelete', (_, result) => {...})

Current Issue:

• Callbacks don't return values (templates can't use reactive helpers with Meteor.call callbacks)
• Requires separate async calls for each setting
• Falls back to unresponsive UI

Recommended Solution:

• Use existing accountSettings publication (already exists in server/publications/accountSettings.js)
• Create reactive helpers that read from AccountSettings collection instead
• Subscribe to accountSettings in userHeader template

Benefits:

• Instant rendering with cached data
• Reactive updates if settings change
• No network round-trip for initial render
• Saves 3 Meteor.call() per profile popup load

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3. cron.getJobs - Polling Every 2 Seconds

Location: imports/cronMigrationClient.js line 62-67, called every 2 seconds Current Issue:

• Fetches list of all cron jobs every 2 seconds
• RPC overhead even when jobs list hasn't changed

Recommended Solution:

• Create cronJobs publication in server/publications/cronJobs.js
• Publish CronJobStatus.find({}) for admin users
• Subscribe on client, use collection directly instead of polling

Benefits:

• Real-time updates via DDP instead of polling
• Reduced server load
• Lower latency for job status changes

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4. toggleGreyIcons, setAvatarUrl - User Preference Updates

Location: client/components/users/userHeader.js lines 103, 223 Current Pattern:

Meteor.call('toggleGreyIcons', (err) => {...})
Meteor.call('setAvatarUrl', avatarUrl, (err) => {...})

Recommended Solution:

• These are write operations (correct for Meteor.call)
• Keep Meteor.call but ensure subscribed data reflects changes immediately
• Current user subscription should update reactively after call completes

Status: ✅ Already correct pattern

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5. setBoardView, setListCollapsedState, setSwimlaneCollapsedState

Location: client/lib/utils.js lines 293, 379, 420 Current Pattern: Write operations via Meteor.call Status: ✅ Already correct pattern (mutations should use Meteor.call)

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MODERATE OPPORTUNITIES (Medium Impact)

6. getCustomUI, getMatomoConf - Configuration Data

Location: client/lib/utils.js lines 748, 799 Current Issue:

• Fetches config data that rarely changes
• Every template that needs it makes a separate call

Recommended Solution:

• Create customUI and matomoConfig publications
• Cache on client, subscribe once globally
• Much faster for repeated access

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7. Attachment Migration Status - Multiple Calls

Location: client/lib/attachmentMigrationManager.js lines 66, 142, 169 Methods:

• attachmentMigration.isBoardMigrated
• attachmentMigration.migrateBoardAttachments
• attachmentMigration.getProgress

Recommended Solution:

• Create attachmentMigrationStatus publication
• Publish board migration status for boards user has access to
• Subscribe to get migration state reactively

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8. Position History Tracking - Fire-and-Forget Operations

Location: client/lib/originalPositionHelpers.js lines 12, 26, 40, 54, 71 Methods:

• positionHistory.trackSwimlane
• positionHistory.trackList
• positionHistory.trackCard
• Undo/redo methods

Current: These are write operations Status: ✅ Correct to use Meteor.call (not candidates for pub/sub)

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ALREADY OPTIMIZED ✅

These are already using pub/sub properly:

• Meteor.subscribe('setting') - Global settings
• Meteor.subscribe('board', boardId) - Board data
• Meteor.subscribe('notificationActivities') - Notifications
• Meteor.subscribe('sessionData') - User session data
• Meteor.subscribe('my-avatars') - User avatars
• Meteor.subscribe('userGreyIcons') - User preferences
• Meteor.subscribe('accountSettings') - Account settings
• Meteor.subscribe('cronMigrationStatus') - Migration status (just implemented)

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IMPLEMENTATION PRIORITY

Priority 1 (Quick Wins - 30 mins)

1. Fix AccountSettings helpers - Use published data instead of Meteor.call
   • Replace callbacks in templates with reactive collection access
   • Already subscribed, just need to use it

Priority 2 (Medium Effort - 1 hour)

2. Add cronJobs publication - Replace polling with pub/sub
3. Add customUI publication - Cache config data
4. Add matomoConfig publication - Cache config data

Priority 3 (Larger Effort - 2 hours)

5. Add attachmentMigrationStatus publication - Multiple methods become reactive
6. Optimize cron.getMigrationProgress - Further reduce polling if needed

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PERMISSION PRESERVATION

All recommended changes maintain existing permission model:

• accountSettings: Already published to all users
• cronJobs/cronMigrationStatus: Publish only to admin users (check in publication)
• attachmentMigrationStatus: Publish only to boards user is member of
• customUI/matomoConfig: Publish to all users (public config)

No security changes needed - just move from Meteor.call to pub/sub with same permission checks.

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PERFORMANCE IMPACT ESTIMATION

Current State (with polling)

• 1 poll call every 2 seconds = 30 calls/minute per client
• 10 admin clients = 300 calls/minute to server
• High DDP message traffic

After Optimization

• 1 subscription = 1 initial sync + reactive updates only
• 10 admin clients = 10 subscriptions total
• 90% reduction in RPC overhead
• Sub-100ms updates instead of up to 2000ms latency