Files
paperless-ngx/src/paperless_ai/vector_store.py
T
stumpylog f0311e77d4 feat(ai): atomic upsert_document on the LanceDB store
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
2026-06-03 09:41:05 -07:00

228 lines
8.2 KiB
Python

import json
import logging
from collections.abc import Sequence
from typing import Any
import lancedb
import pyarrow as pa
from llama_index.core.bridge.pydantic import PrivateAttr
from llama_index.core.schema import BaseNode
from llama_index.core.vector_stores.types import BasePydanticVectorStore
from llama_index.core.vector_stores.types import FilterCondition
from llama_index.core.vector_stores.types import FilterOperator
from llama_index.core.vector_stores.types import MetadataFilters
from llama_index.core.vector_stores.types import VectorStoreQuery
from llama_index.core.vector_stores.types import VectorStoreQueryResult
from llama_index.core.vector_stores.utils import metadata_dict_to_node
from llama_index.core.vector_stores.utils import node_to_metadata_dict
logger = logging.getLogger("paperless_ai.vector_store")
DEFAULT_TABLE_NAME = "documents"
def _escape(value: str) -> str:
return str(value).replace("'", "''")
def _build_where(filters: MetadataFilters | None) -> str | None:
"""Translate the EQ / IN filters we use into a Lance SQL predicate on the
top-level ``document_id`` column."""
if filters is None or not filters.filters:
return None
clauses: list[str] = []
for f in filters.filters:
if f.operator == FilterOperator.IN:
vals = ",".join(f"'{_escape(v)}'" for v in f.value)
clauses.append(f"{f.key} IN ({vals})")
elif f.operator == FilterOperator.EQ:
clauses.append(f"{f.key} = '{_escape(f.value)}'")
else: # pragma: no cover - we only ever build EQ/IN filters
raise NotImplementedError(f"Unsupported filter operator: {f.operator}")
joiner = " OR " if filters.condition == FilterCondition.OR else " AND "
return joiner.join(clauses)
class PaperlessLanceVectorStore(BasePydanticVectorStore):
"""A llama-index vector store backed directly by a LanceDB table.
Stores one row per node with the node id, its document id (both as the
``ref_doc_id`` delete key ``doc_id`` and a top-level filter column
``document_id``), the embedding, and the serialised node (text + metadata)
as JSON. ``stores_text`` lets llama-index run off this store alone, with no
separate docstore or index store.
"""
stores_text: bool = True
flat_metadata: bool = True
_uri: str = PrivateAttr()
_table_name: str = PrivateAttr()
_conn: Any = PrivateAttr()
_table: Any = PrivateAttr()
def __init__(self, uri: str, table_name: str = DEFAULT_TABLE_NAME) -> None:
super().__init__()
self._uri = uri
self._table_name = table_name
self._conn = lancedb.connect(uri)
existing = self._conn.list_tables().tables
self._table = (
self._conn.open_table(table_name) if table_name in existing else None
)
@property
def client(self) -> Any:
return self._conn
def table_exists(self) -> bool:
return self._table_name in self._conn.list_tables().tables
def vector_dim(self) -> int | None:
if self._table is None:
return None
return self._table.schema.field("vector").type.list_size
def drop_table(self) -> None:
if self.table_exists():
self._conn.drop_table(self._table_name)
self._table = None
@staticmethod
def _schema(dim: int) -> pa.Schema:
return pa.schema(
[
pa.field("id", pa.string()),
pa.field("doc_id", pa.string()),
pa.field("document_id", pa.string()),
pa.field("vector", pa.list_(pa.float32(), dim)),
pa.field("node_content", pa.string()),
],
)
def _row(self, node: BaseNode) -> dict[str, Any]:
meta = node_to_metadata_dict(
node,
remove_text=False,
flat_metadata=self.flat_metadata,
)
return {
"id": node.node_id,
"doc_id": node.ref_doc_id,
"document_id": str(node.metadata.get("document_id")),
"vector": node.get_embedding(),
"node_content": json.dumps(meta),
}
def add(self, nodes: Sequence[BaseNode], **add_kwargs: Any) -> list[str]:
if not nodes:
return []
rows = [self._row(node) for node in nodes]
if self._table is None:
dim = len(nodes[0].get_embedding())
self._table = self._conn.create_table(
self._table_name,
rows,
schema=self._schema(dim),
)
else:
self._table.add(rows)
return [node.node_id for node in nodes]
def upsert_document(self, document_id: str, nodes: list[BaseNode]) -> list[str]:
"""Atomically replace all stored chunks of ``document_id`` with ``nodes``.
A single ``merge_insert`` commit: matching node ids are updated, new ids
inserted, and any existing rows for this document that are not in the new
set are deleted (``when_not_matched_by_source_delete``). This prunes stale
trailing chunks when an edit reduces a document's chunk count, with no
transient empty state for concurrent lock-free readers.
"""
if not nodes:
# No indexable content: treat as a removal.
self.delete(document_id)
return []
rows = [self._row(node) for node in nodes]
if self._table is None:
dim = len(nodes[0].get_embedding())
self._table = self._conn.create_table(
self._table_name,
rows,
schema=self._schema(dim),
)
return [node.node_id for node in nodes]
(
self._table.merge_insert("id")
.when_matched_update_all()
.when_not_matched_insert_all()
.when_not_matched_by_source_delete(
f"document_id = '{_escape(document_id)}'",
)
.execute(rows)
)
return [node.node_id for node in nodes]
def delete(self, ref_doc_id: str, **delete_kwargs: Any) -> None:
if self._table is not None:
self._table.delete(f"doc_id = '{_escape(ref_doc_id)}'")
def delete_nodes(
self,
node_ids: list[str] | None = None,
filters: MetadataFilters | None = None,
**delete_kwargs: Any,
) -> None:
if self._table is None:
return
if node_ids:
ids = ",".join(f'"{_escape(n)}"' for n in node_ids)
self._table.delete(f"id IN ({ids})")
elif filters is not None:
where = _build_where(filters)
if where:
self._table.delete(where)
def _rows_to_nodes(self, rows: list[dict[str, Any]]) -> list[BaseNode]:
nodes: list[BaseNode] = []
for row in rows:
node = metadata_dict_to_node(json.loads(row["node_content"]))
node.embedding = list(row["vector"])
nodes.append(node)
return nodes
def get_nodes(
self,
node_ids: list[str] | None = None,
filters: MetadataFilters | None = None,
**kwargs: Any,
) -> list[BaseNode]:
if self._table is None:
return []
query = self._table.search()
where = _build_where(filters)
if node_ids:
ids = ",".join(f'"{_escape(n)}"' for n in node_ids)
query = query.where(f"id IN ({ids})")
elif where:
query = query.where(where)
return self._rows_to_nodes(query.to_list())
def query(
self,
query: VectorStoreQuery,
**kwargs: Any,
) -> VectorStoreQueryResult:
if self._table is None:
return VectorStoreQueryResult(nodes=[], similarities=[], ids=[])
top_k = query.similarity_top_k if query.similarity_top_k is not None else 10
search = self._table.search(query.query_embedding).limit(top_k)
where = _build_where(query.filters)
if where:
search = search.where(where)
rows = search.to_list()
nodes = self._rows_to_nodes(rows)
# LanceDB returns an L2 distance (smaller = closer); map to a descending similarity.
sims = [1.0 / (1.0 + float(row["_distance"])) for row in rows]
ids = [row["id"] for row in rows]
return VectorStoreQueryResult(nodes=nodes, similarities=sims, ids=ids)