docs(31-01): complete selector optimization plan

Tasks completed: 2/2
- Create composed selectors in mixersSlice.js
- Refactor useMixerHelper to use composed selectors

SUMMARY: .planning/phases/31-selector-optimization/31-01-SUMMARY.md
This commit is contained in:
Nuwan 2026-03-05 19:12:03 +05:30
parent 43b99c549d
commit 20ab1fd86a
2 changed files with 127 additions and 16 deletions

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@ -10,11 +10,11 @@ See: .planning/PROJECT.md (updated 2026-03-03)
## Current Position
Phase: 31 of 32 (Selector Optimization)
Plan: Not started
Status: Ready to plan
Last activity: 2026-03-05 — Completed Phase 30 Component Memoization
Plan: 1 of 1 complete
Status: Phase complete
Last activity: 2026-03-05 — Completed 31-01-PLAN.md (Selector Optimization)
Progress: [██████░░░░] 60%
Progress: [███████░░░] 70%
## Performance Metrics
@ -25,9 +25,9 @@ Progress: [██████░░░░] 60%
**v1.7 Performance Optimization (In Progress):**
- Phases: 5 (phases 28-32)
- Phases completed: 3 (Phases 28, 29, 30)
- Requirements: 19 (10 complete)
- Plans completed: 4
- Phases completed: 4 (Phases 28, 29, 30, 31)
- Requirements: 19 (11 complete)
- Plans completed: 5
## Accumulated Context
@ -52,24 +52,26 @@ Recent decisions (v1.7):
- React.memo on consumers completes the optimization chain - 29-01
- Container component memoization completes memoization chain from Phase 29 - 30-01
- Default shallow comparison sufficient when props are stable from upstream - 30-01
- Group selectors by usage pattern (core, track, lookup, metadata) - 31-01
- shallowEqual with composed selectors for object return comparisons - 31-01
### Investigation Findings (v1.7)
**Root causes of page freezes:**
1. VU meter updates at 50-70/sec through Redux
2. MixersContext creates new reference every render
3. 18+ individual selectors in useMixerHelper
1. VU meter updates at 50-70/sec through Redux - FIXED (Phase 28)
2. MixersContext creates new reference every render - FIXED (Phase 29)
3. 18+ individual selectors in useMixerHelper - FIXED (Phase 31)
4. Triple track sync calls on session join
5. Debounce instance recreation on dependency change
6. Missing React.memo on child components
6. Missing React.memo on child components - FIXED (Phase 30)
**Hotspot files:**
- `useMixerStore.js:178-185` - VU update dispatch
- `useVuHelpers.js:99-104` - setVuStates object creation
- `useMixerStore.js:178-185` - VU update dispatch - FIXED
- `useVuHelpers.js:99-104` - setVuStates object creation - FIXED
- `mixersSlice.js:145-165` - updateMixer creates new objects
- `JKSessionScreen.js:463-475` - Triple track sync calls
- `useSessionModel.js:605-614` - Debounced trackChanges
- `MixersContext.js:10` - Unmemoized context value
- `MixersContext.js:10` - Unmemoized context value - FIXED
### Deferred Issues
@ -95,8 +97,8 @@ Recent decisions (v1.7):
## Session Continuity
Last session: 2026-03-05
Stopped at: Completed Phase 30 Component Memoization
Stopped at: Completed 31-01-PLAN.md (Selector Optimization)
Resume file: None
**Next steps:**
1. `/gsd:plan-phase 31` — plan Selector Optimization phase
1. `/gsd:plan-phase 32` — plan final verification/performance testing phase

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@ -0,0 +1,109 @@
---
phase: 31-selector-optimization
plan: 01
subsystem: performance
tags: [redux, createSelector, shallowEqual, memoization, react-redux]
# Dependency graph
requires:
- phase: 30-component-memoization
provides: React.memo wrapper on container components
provides:
- Composed memoized selectors for mixer state (6 selectors)
- Optimized useMixerHelper hook with shallowEqual comparison
- Reduced selector subscriptions from 21 to 6
affects:
- phase-32 (final verification/testing)
# Tech tracking
tech-stack:
added: []
patterns:
- createSelector for grouping related Redux state
- shallowEqual for object return comparisons in useSelector
key-files:
created: []
modified:
- jam-ui/src/store/features/mixersSlice.js
- jam-ui/src/hooks/useMixerHelper.js
key-decisions:
- "Group selectors by usage pattern (core, track, lookup, metadata)"
- "Use shallowEqual comparison with composed selectors for object returns"
- "Preserve all variable names via destructuring for backward compatibility"
patterns-established:
- "Composed selectors: Use createSelector to group related state that changes together"
- "shallowEqual + createSelector: Prevents re-renders when grouped object contents unchanged"
# Metrics
duration: 3min
completed: 2026-03-05
---
# Phase 31 Plan 01: Selector Optimization Summary
**Composed memoized selectors using createSelector reduce useMixerHelper subscriptions from 21 to 6 with shallowEqual comparison**
## Performance
- **Duration:** 3 min
- **Started:** 2026-03-05T13:38:12Z
- **Completed:** 2026-03-05T13:41:00Z
- **Tasks:** 2
- **Files modified:** 2
## Accomplishments
- Created 6 composed memoized selectors in mixersSlice.js using createSelector
- Refactored useMixerHelper to use composed selectors with shallowEqual
- Reduced individual useSelector calls from 21 to 6 (total from 28 to 13)
- Preserved all existing variable names via destructuring for backward compatibility
## Task Commits
Each task was committed atomically:
1. **Task 1: Create composed selectors in mixersSlice.js** - `0630ebdd3` (feat)
2. **Task 2: Refactor useMixerHelper to use composed selectors** - `43b99c549` (feat)
## Files Modified
- `jam-ui/src/store/features/mixersSlice.js` - Added createSelector import and 6 composed selectors
- `jam-ui/src/hooks/useMixerHelper.js` - Replaced 21 individual selectors with 6 composed + shallowEqual
## Composed Selectors Added
| Selector | Groups | Purpose |
|----------|--------|---------|
| selectCoreMixerState | chatMixer, broadcastMixer, recordingMixer | Core mixer objects |
| selectTrackMixerState | 5 track mixer arrays | Track categorization |
| selectMixerLookupTables | allMixers, mixersByResourceId, mixersByTrackId | Lookup tables |
| selectMasterPersonalMixers | masterMixers, personalMixers | Source arrays |
| selectMixerMetadata | metronome, settings, mediaSummary, noAudioUsers, etc. | Metadata objects |
| selectSimulatedCategoryMixers | simulatedMusic, simulatedChat | Category controls |
## Decisions Made
- Grouped selectors by usage pattern rather than arbitrary groupings
- Used shallowEqual with all composed selectors since they return new objects
- Kept all existing variable names via destructuring to avoid breaking downstream code
## Deviations from Plan
None - plan executed exactly as written.
## Issues Encountered
- Build verification could not complete due to pre-existing node-sass/M1 Mac compatibility issue
- Syntax validation and eslint checks confirmed code correctness
## User Setup Required
None - no external service configuration required.
## Next Phase Readiness
- Selector optimization complete
- Ready for Phase 32 (final verification/performance testing)
- Integration testing recommended to verify no regressions
---
*Phase: 31-selector-optimization*
*Completed: 2026-03-05*