PROBLEM:
Request coalescing infrastructure (inflightLIDLookups, inflightPNLookups Maps
and coalesceRequest() method) was implemented in commit a9374bd but never
integrated into the public API. The Maps remained empty and the coalescing
method was never called, wasting the optimization potential.
In message burst scenarios (10+ concurrent messages from same user), each
concurrent call to getLIDForPN() would execute a separate database lookup
for the same user, causing:
- Redundant database queries (9 wasted queries in 10 concurrent calls)
- Increased database load during high traffic
- Higher latency for duplicate lookups
- Missed optimization opportunity
SOLUTION:
Integrated request coalescing into single-item lookup methods:
1. getLIDForPN(pn): Now uses coalesceRequest() with inflightLIDLookups Map
- First concurrent call creates Promise and stores in Map
- Subsequent calls for same PN return existing Promise
- Result: 1 DB lookup shared by all concurrent calls
2. getPNForLID(lid): Now uses coalesceRequest() with inflightPNLookups Map
- Same deduplication pattern for reverse lookups
- Optimizes LID→PN translation in message processing
3. Updated Maps documentation to reflect active usage
- Clarified that Maps are now actively used (not "future optimization")
- Documented usage in getLIDForPN() and getPNForLID()
Implementation Details:
- Both methods now use trackOperation() wrapper (ensures thread safety via V4)
- Early validation before coalescing (isAnyPnUser/isAnyLidUser, jidDecode)
- Coalescing keyed by user (not full JID) for maximum deduplication
- Batch methods (getLIDsForPNs, getPNsForLIDs) unchanged (already optimized)
BENEFITS:
- Reduces DB load by 90% in 10-concurrent-call burst scenarios
- Improves latency for duplicate lookups (instant return from existing Promise)
- No downside: if no concurrency, behaves exactly as before
- Completes optimization work started in commit a9374bd
SAFETY:
✓ Protected by trackOperation() (V4 fix - prevents UAF during destroy)
✓ Maps cleared in destroy() (V5 fix - prevents memory leaks)
✓ No TOCTOU in coalesceRequest() (V6 fix - single check at operation start)
✓ Thread-safe: Maps protected by operationsInProgress counter
VALIDATION:
✓ Protocolo de Análise complete (5 steps)
✓ TypeScript compilation verified (no new errors)
✓ E2E scenarios simulated (burst of 10 concurrent calls)
✓ Backward compatible (batch methods unchanged, single methods enhanced)
FILES MODIFIED:
- src/Signal/lid-mapping.ts:165-181 - Updated Maps documentation (now active)
- src/Signal/lid-mapping.ts:470-502 - Integrated coalescing in getLIDForPN()
- src/Signal/lid-mapping.ts:659-691 - Integrated coalescing in getPNForLID()
https://claude.ai/code/session_01NTVq3RHgGpgKL289JGvw55
Claude
48ec5c658a