Files
hyungi_document_server/app/services/search/retrieval_service.py
Hyungi Ahn 22117a2a6d feat(search): Phase 1.2-AB — migration 016 + trigram retrieval
migration 016: documents FTS 확장 + trigram 인덱스 (1.5초 빌드)
- idx_documents_fts_full — title+ai_tags+ai_summary+user_note+extracted_text 통합 FTS
- idx_documents_title_trgm — title 단독 trigram
- idx_documents_extracted_text_trgm — 본문 trigram (NULL 제외)
- idx_documents_ai_summary_trgm — AI 요약 trigram
- CONCURRENTLY 불필요 (765 docs / 6.5MB)

retrieval_service.search_text: ILIKE 완전 제거 → trigram % + similarity()
- WHERE: title %, ai_summary %, FTS @@ (모두 인덱스 활용)
- ORDER BY: 5컬럼 similarity 가중 합산 + ts_rank * 2.0
- 가중치 그대로 (title 3.0 / tags 2.5 / note 2.0 / summary 1.5 / extracted 1.0)
- threshold default 0.3 (필요 시 set_limit으로 조정)

목표: text_ms 470ms → 100~200ms (ILIKE 풀스캔 제거 효과)
2026-04-07 14:36:22 +09:00

125 lines
5.2 KiB
Python

"""검색 후보 수집 서비스 (Phase 1.2).
text(documents FTS + trigram) + vector(documents.embedding → chunks) 후보를
SearchResult 리스트로 반환.
Phase 1.1a: search.py의 _search_text/_search_vector를 이전 (ILIKE 그대로).
Phase 1.2-B: ILIKE → trigram `%` + `similarity()`. ILIKE 풀 스캔 제거.
Phase 1.2-B 이후: vector retrieval을 document_chunks 테이블 기반으로 전환.
"""
from __future__ import annotations
from typing import TYPE_CHECKING
from sqlalchemy import text
from sqlalchemy.ext.asyncio import AsyncSession
from ai.client import AIClient
if TYPE_CHECKING:
from api.search import SearchResult
async def search_text(
session: AsyncSession, query: str, limit: int
) -> list["SearchResult"]:
"""FTS + trigram 필드별 가중치 검색 (Phase 1.2-B).
WHERE: 인덱스 있는 trigram 컬럼(title, ai_summary)으로 후보 필터 + FTS 통합 인덱스
- idx_documents_title_trgm
- idx_documents_ai_summary_trgm
- idx_documents_fts_full (title + ai_tags + ai_summary + user_note + extracted_text)
- extracted_text는 trigram threshold 0.3에서 매우 낮은 similarity → WHERE에선 FTS만
ORDER BY: 5개 컬럼 similarity 가중 합산 + ts_rank * 2.0
가중치: title 3.0 / ai_tags 2.5 / user_note 2.0 / ai_summary 1.5 / extracted_text 1.0
"""
from api.search import SearchResult # 순환 import 회피
result = await session.execute(
text("""
SELECT id, title, ai_domain, ai_summary, file_format,
left(extracted_text, 200) AS snippet,
(
-- 컬럼별 trigram similarity 가중 합산
similarity(coalesce(title, ''), :q) * 3.0
+ similarity(coalesce(ai_tags::text, ''), :q) * 2.5
+ similarity(coalesce(user_note, ''), :q) * 2.0
+ similarity(coalesce(ai_summary, ''), :q) * 1.5
+ similarity(coalesce(extracted_text, ''), :q) * 1.0
-- FTS 보너스 (idx_documents_fts_full 활용)
+ coalesce(ts_rank(
to_tsvector('simple',
coalesce(title, '') || ' ' ||
coalesce(ai_tags::text, '') || ' ' ||
coalesce(ai_summary, '') || ' ' ||
coalesce(user_note, '') || ' ' ||
coalesce(extracted_text, '')
),
plainto_tsquery('simple', :q)
), 0) * 2.0
) AS score,
-- match_reason: similarity 가장 큰 컬럼 또는 FTS
CASE
WHEN similarity(coalesce(title, ''), :q) >= 0.3 THEN 'title'
WHEN similarity(coalesce(ai_tags::text, ''), :q) >= 0.3 THEN 'tags'
WHEN similarity(coalesce(user_note, ''), :q) >= 0.3 THEN 'note'
WHEN similarity(coalesce(ai_summary, ''), :q) >= 0.3 THEN 'summary'
WHEN similarity(coalesce(extracted_text, ''), :q) >= 0.3 THEN 'content'
ELSE 'fts'
END AS match_reason
FROM documents
WHERE deleted_at IS NULL
AND (
-- trigram 후보 필터 (인덱스 있는 짧은 컬럼만)
title % :q
OR (ai_summary IS NOT NULL AND ai_summary % :q)
-- FTS 통합 인덱스
OR to_tsvector('simple',
coalesce(title, '') || ' ' ||
coalesce(ai_tags::text, '') || ' ' ||
coalesce(ai_summary, '') || ' ' ||
coalesce(user_note, '') || ' ' ||
coalesce(extracted_text, '')
) @@ plainto_tsquery('simple', :q)
)
ORDER BY score DESC
LIMIT :limit
"""),
{"q": query, "limit": limit},
)
return [SearchResult(**row._mapping) for row in result]
async def search_vector(
session: AsyncSession, query: str, limit: int
) -> list["SearchResult"]:
"""벡터 유사도 검색 (코사인 거리).
Phase 1.2에서 document_chunks 테이블 기반으로 전환 예정.
현재는 documents.embedding 사용.
"""
from api.search import SearchResult # 순환 import 회피
try:
client = AIClient()
query_embedding = await client.embed(query)
await client.close()
except Exception:
return []
result = await session.execute(
text("""
SELECT id, title, ai_domain, ai_summary, file_format,
(1 - (embedding <=> cast(:embedding AS vector))) AS score,
left(extracted_text, 200) AS snippet,
'vector' AS match_reason
FROM documents
WHERE embedding IS NOT NULL AND deleted_at IS NULL
ORDER BY embedding <=> cast(:embedding AS vector)
LIMIT :limit
"""),
{"embedding": str(query_embedding), "limit": limit},
)
return [SearchResult(**row._mapping) for row in result]