Files
FabledScribe/src/scribe/models/embedding.py
T
bvandeusen 513019786e feat(search): pgvector substrate — vector(384) + HNSW for semantic search
Move semantic_search_notes off the full-table Python cosine scan onto a native
pgvector column: indexed ORDER BY embedding <=> :q LIMIT k (HNSW, cosine).
Migration 0067 enables the extension, converts the JSONB embedding column to
vector(384) (stale-dim rows dropped and regenerated by the startup backfill),
and builds the HNSW cosine index. Postgres image moves postgres:16-alpine ->
pgvector/pgvector:pg17 across prod, quickstart, and CI.

Scribe: project 2, milestone 93, task 1031.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Xz4j1H7pjYSjKsEpgcNH5E
2026-06-22 20:10:15 -04:00

32 lines
1.1 KiB
Python

from datetime import datetime, timezone
from pgvector.sqlalchemy import Vector
from sqlalchemy import DateTime, ForeignKey, Integer
from sqlalchemy.orm import Mapped, mapped_column
from scribe.models import Base
# bge-small-en-v1.5 produces 384-dim unit-normalized vectors. The column is a
# native pgvector `vector(384)` (see migration 0067) so similarity search runs
# as an indexed `ORDER BY embedding <=> :q LIMIT k` in Postgres rather than a
# full-table Python cosine scan.
EMBEDDING_DIM = 384
class NoteEmbedding(Base):
"""Stores the embedding vector for a note, used for semantic search."""
__tablename__ = "note_embeddings"
note_id: Mapped[int] = mapped_column(
Integer,
ForeignKey("notes.id", ondelete="CASCADE"),
primary_key=True,
)
user_id: Mapped[int] = mapped_column(Integer, nullable=False, index=True)
embedding: Mapped[list] = mapped_column(Vector(EMBEDDING_DIM), nullable=False)
updated_at: Mapped[datetime] = mapped_column(
DateTime(timezone=True),
default=lambda: datetime.now(timezone.utc),
)