Kpa-clawbot 01ca843309 perf: move collision analysis to server-side endpoint (fixes #386) (#415) ...

## Summary

Moves the hash collision analysis from the frontend to a new server-side
endpoint, eliminating a major performance bottleneck on the analytics
collision tab.

Fixes #386

## Problem

The collision tab was:
1. **Downloading all nodes** (`/nodes?limit=2000`) — ~500KB+ of data
2. **Running O(n²) pairwise distance calculations** on the browser main
thread (~2M comparisons with 2000 nodes)
3. **Building prefix maps client-side** (`buildOneBytePrefixMap`,
`buildTwoBytePrefixInfo`, `buildCollisionHops`) iterating all nodes
multiple times

## Solution

### New endpoint: `GET /api/analytics/hash-collisions`

Returns pre-computed collision analysis with:
- `inconsistent_nodes` — nodes with varying hash sizes
- `by_size` — per-byte-size (1, 2, 3) collision data:
  - `stats` — node counts, space usage, collision counts
- `collisions` — pre-computed collisions with pairwise distances and
classifications (local/regional/distant/incomplete)
  - `one_byte_cells` — 256-cell prefix map for 1-byte matrix rendering
- `two_byte_cells` — first-byte-grouped data for 2-byte matrix rendering

### Caching

Uses the existing `cachedResult` pattern with a new `collisionCache`
map. Invalidated on `hasNewTransmissions` (same trigger as the
hash-sizes cache) and on eviction.

### Frontend changes

- `renderCollisionTab` now accepts pre-fetched `collisionData` from the
parallel API load
- New `renderHashMatrixFromServer` and `renderCollisionsFromServer`
functions consume server-computed data directly
- No more `/nodes?limit=2000` fetch from the collision tab
- Old client-side functions (`buildOneBytePrefixMap`, etc.) preserved
for test helper exports

## Test results

- `go test ./...` (server): ✅ pass
- `go test ./...` (ingestor): ✅ pass
- `test-packet-filter.js`: ✅ 62 passed
- `test-aging.js`: ✅ 29 passed
- `test-frontend-helpers.js`: ✅ 227 passed

## Performance impact

| Metric | Before | After |
|--------|--------|-------|
| Data transferred | ~500KB (all nodes) | ~50KB (collision data only) |
| Client computation | O(n²) distance calc | None (server-cached) |
| Main thread blocking | Yes (2000 nodes × pairwise) | No |
| Server caching | N/A | 15s TTL, invalidated on new transmissions |

---------

Co-authored-by: you <you@example.com>
Co-authored-by: Kpa-clawbot <kpabap+clawdbot@gmail.com>

2026-04-01 09:21:23 -07:00

..

ingestor

fix: extract score/direction from MQTT, strip units, fix type safety issues (#371)

2026-04-01 07:26:23 -07:00

server

perf: move collision analysis to server-side endpoint (fixes #386) (#415)

2026-04-01 09:21:23 -07:00