---
id: S01
parent: M015
milestone: M015
provides:
  - GET /api/v1/search/popular endpoint returning PopularSearchesResponse JSON
  - search_log PostgreSQL table with query logging from all non-empty searches
requires:
  []
affects:
  - S04
key_files:
  - backend/models.py
  - backend/schemas.py
  - backend/routers/search.py
  - alembic/versions/013_add_search_log.py
key_decisions:
  - D025: PostgreSQL search_log + Redis read-through cache with 5-min TTL (collaborative, already recorded)
  - Fire-and-forget asyncio.create_task with independent session for non-blocking logging
  - Integer PK for SearchLog (append-only analytics, no need for UUID)
patterns_established:
  - Fire-and-forget async logging via asyncio.create_task with independent session and catch-all exception handling
  - Redis read-through cache pattern: check Redis → cache miss → DB query → SET with TTL → return
observability_surfaces:
  - GET /search/popular cached flag indicates whether result came from Redis or DB
  - search_log table queryable for analytics: zero-result queries, time-of-day patterns, query frequency
drill_down_paths:
  - .gsd/milestones/M015/slices/S01/tasks/T01-SUMMARY.md
  - .gsd/milestones/M015/slices/S01/tasks/T02-SUMMARY.md
duration: ""
verification_result: passed
completed_at: 2026-04-03T04:08:38.241Z
blocker_discovered: false
---

# S01: Search Query Logging + Popular Searches API

**Backend search query logging to PostgreSQL with fire-and-forget pattern, and GET /search/popular endpoint with Redis read-through cache (5-min TTL, 7-day window, LOWER normalization).**

## What Happened

Added SearchLog model (Integer PK, indexed query + created_at columns) with Alembic migration 013 creating the search_log table. Added PopularSearchItem and PopularSearchesResponse Pydantic schemas. Implemented non-blocking _log_search async helper that opens an independent session and catches all exceptions — hooked into the search handler via asyncio.create_task for non-empty queries only. Added GET /search/popular endpoint with Redis read-through cache (key: chrysopedia:popular_searches, 300s TTL). Cache miss queries search_log with LOWER(query) normalization and 7-day window, returning top 10. Redis failures fall through gracefully to the DB query.

Deployed to ub01: pushed to origin, rebuilt API/worker containers, applied Alembic migration 013, restarted nginx for stale DNS. Verified end-to-end: real searches create search_log rows, empty queries are excluded, GET /search/popular returns valid JSON with items array and cached flag. Three search_log rows confirmed after test queries.

## Verification

1. `cd backend && python -c "from models import SearchLog; print(SearchLog.__tablename__)"` → search_log ✅
2. `cd backend && python -c "from schemas import PopularSearchItem, PopularSearchesResponse; print('OK')"` → OK ✅
3. `cd backend && python -c "from routers.search import router; routes = [r.path for r in router.routes]; assert '/search/popular' in routes; print('OK')"` → OK ✅
4. `curl -sf 'http://ub01:8096/api/v1/search/popular'` → {"items":[{"query":"reverb","count":1}],"cached":true} ✅
5. `ssh ub01 "docker exec chrysopedia-db psql -U chrysopedia -t -c 'SELECT count(*) FROM search_log;'"` → 3 ✅
6. Empty query guard: sent empty and whitespace-only queries, count stayed at 3 ✅

## Requirements Advanced

- R035 — Backend half delivered: search queries logged to PostgreSQL, popular endpoint returns cached top-N from last 7 days. Frontend display deferred to S04.

## Requirements Validated

None.

## New Requirements Surfaced

None.

## Requirements Invalidated or Re-scoped

None.

## Deviations

Slice plan verification checks '/popular' in router routes but APIRouter stores full prefix paths ('/search/popular'). Minor spec mismatch — adjusted assertions. Docker Compose service name is 'chrysopedia-web' not 'chrysopedia-web-8096' as referenced in CLAUDE.md.

## Known Limitations

Popular searches endpoint returns results from a single-node PostgreSQL — no read replicas. At current scale (single-admin tool) this is fine. Redis cache key is global — no per-scope popular queries yet.

## Follow-ups

S04 (Trending Searches Homepage Block) will consume GET /search/popular from the frontend. No backend changes needed for S04.

## Files Created/Modified

- `backend/models.py` — Added SearchLog model with Integer PK, query (indexed), scope, result_count, created_at (indexed)
- `backend/schemas.py` — Added PopularSearchItem and PopularSearchesResponse Pydantic schemas
- `backend/routers/search.py` — Added _log_search fire-and-forget helper and GET /search/popular endpoint with Redis cache
- `alembic/versions/013_add_search_log.py` — Alembic migration creating search_log table with indexes on query and created_at
