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195 | class PGVectorStore(VectorStore):
"""Vector store backed by PostgreSQL with pgvector extension.
Requires ``asyncpg`` + ``pgvector`` (install via ``teff[embedding]``).
Metadata is stored in a ``jsonb`` column; filters are translated into
SQL ``WHERE`` clauses on the top-level JSON keys.
The schema (``vector`` extension + table with a primary key on
``doc_id``) is bootstrapped lazily on the first connection, and ``add``
is idempotent (``ON CONFLICT DO UPDATE``) so re-embedding a document or
a fresh process re-indexing the same queue never duplicates rows.
"""
def __init__(self, dsn: str, table: str = "teff_vectors", dim: int = 768):
import importlib.util
if importlib.util.find_spec("asyncpg") is None:
raise ImportError("install asyncpg + pgvector for PGVectorStore")
self._dsn = dsn
self._table = table
self._dim = dim
async def _connect(self):
import asyncpg
import pgvector.asyncpg
conn = await asyncpg.connect(self._dsn)
await pgvector.asyncpg.register_vector(conn)
await conn.execute("CREATE EXTENSION IF NOT EXISTS vector")
await conn.execute(
f"CREATE TABLE IF NOT EXISTS {self._table} ("
f"doc_id TEXT PRIMARY KEY, "
f"embedding vector({self._dim}) NOT NULL, "
f"metadata JSONB NOT NULL)"
)
return conn
async def add(self, vectors: list[tuple[str, list[float], dict]]) -> None:
import json
conn = await self._connect()
try:
await conn.executemany(
f"INSERT INTO {self._table} (doc_id, embedding, metadata) "
f"VALUES ($1, $2::vector, $3::jsonb) "
f"ON CONFLICT (doc_id) DO UPDATE SET "
f"embedding = EXCLUDED.embedding, metadata = EXCLUDED.metadata",
[
(vid, vec, json.dumps(meta, ensure_ascii=False))
for vid, vec, meta in vectors
],
)
finally:
await conn.close()
def _where_clause(self, filter: dict | None) -> tuple[str, list]:
"""Build ``(sql_where, params)`` from the filter DSL.
``$1`` is reserved for the query vector, so metadata parameters
start at ``$2``. Metadata values are compared as text.
"""
if not filter:
return "", []
params: list = []
def build(node: dict) -> str:
subs: list[str] = []
for key, cond in node.items():
if key in ("$and", "$or"):
op = " AND " if key == "$and" else " OR "
inner = [build(c) for c in cond]
inner = [s for s in inner if s]
if inner:
subs.append("(" + op.join(inner) + ")")
elif isinstance(cond, list):
ph = ", ".join(
"$" + str(len(params) + 2 + i) for i in range(len(cond))
)
subs.append(f"metadata->>'{key}' IN ({ph})")
params.extend(str(c) for c in cond)
else:
params.append(str(cond))
subs.append(f"metadata->>'{key}' = ${len(params) + 1}")
return " AND ".join(subs)
return build(filter), params
async def search(
self,
query: list[float],
k: int = 10,
filter: dict | None = None,
hybrid: bool = False,
query_text: str | None = None,
) -> list[tuple[str, float, dict]]:
import json
where, params = self._where_clause(filter)
conn = await self._connect()
try:
sql = (
f"SELECT doc_id, 1 - (embedding <=> $1::vector) AS score, metadata "
f"FROM {self._table}"
)
if where:
sql += " WHERE " + where
sql += f" ORDER BY embedding <=> $1::vector LIMIT ${len(params) + 1}"
rows = await conn.fetch(sql, query, *params, k)
return [
(r["doc_id"], float(r["score"]), json.loads(r["metadata"]))
for r in rows
]
finally:
await conn.close()
async def delete(self, ids: list[str]) -> None:
conn = await self._connect()
try:
await conn.execute(
f"DELETE FROM {self._table} WHERE doc_id = ANY($1)",
ids,
)
finally:
await conn.close()
async def count(self) -> int:
conn = await self._connect()
try:
row = await conn.fetchval(f"SELECT COUNT(*) FROM {self._table}")
return int(row)
finally:
await conn.close()
async def entries(
self, limit: int = 100, offset: int = 0
) -> list[tuple[str, dict]]:
import json
conn = await self._connect()
try:
rows = await conn.fetch(
f"SELECT doc_id, metadata FROM {self._table} "
f"ORDER BY doc_id LIMIT $1 OFFSET $2",
limit,
offset,
)
return [(r["doc_id"], json.loads(r["metadata"])) for r in rows]
finally:
await conn.close()
async def get(self, ids: list[str]) -> list[tuple[str, dict]]:
import json
conn = await self._connect()
try:
rows = await conn.fetch(
f"SELECT doc_id, metadata FROM {self._table} WHERE doc_id = ANY($1)",
ids,
)
return [(r["doc_id"], json.loads(r["metadata"])) for r in rows]
finally:
await conn.close()
async def update_metadata(self, id: str, metadata: dict) -> None:
import json
conn = await self._connect()
try:
row = await conn.fetchrow(
f"SELECT metadata FROM {self._table} WHERE doc_id = $1", id
)
if row is None:
return
merged = {**json.loads(row["metadata"]), **metadata}
await conn.execute(
f"UPDATE {self._table} SET metadata = $2::jsonb WHERE doc_id = $1",
id,
json.dumps(merged),
)
finally:
await conn.close()
async def clear(self) -> None:
conn = await self._connect()
try:
await conn.execute(f"DELETE FROM {self._table}")
finally:
await conn.close()
|