Source code for langchain_community.vectorstores.tencentvectordb

"""Wrapper around the Tencent vector database."""
from __future__ import annotations

import json
import logging
import time
from typing import Any, Dict, Iterable, List, Optional, Tuple

import numpy as np
from langchain_core.documents import Document
from langchain_core.embeddings import Embeddings
from langchain_core.utils import guard_import
from langchain_core.vectorstores import VectorStore

from langchain_community.vectorstores.utils import maximal_marginal_relevance

logger = logging.getLogger(__name__)


[docs]class ConnectionParams: """Tencent vector DB Connection params. See the following documentation for details: https://cloud.tencent.com/document/product/1709/95820 Attribute: url (str) : The access address of the vector database server that the client needs to connect to. key (str): API key for client to access the vector database server, which is used for authentication. username (str) : Account for client to access the vector database server. timeout (int) : Request Timeout. """
[docs] def __init__(self, url: str, key: str, username: str = "root", timeout: int = 10): self.url = url self.key = key self.username = username self.timeout = timeout
[docs]class IndexParams: """Tencent vector DB Index params. See the following documentation for details: https://cloud.tencent.com/document/product/1709/95826 """
[docs] def __init__( self, dimension: int, shard: int = 1, replicas: int = 2, index_type: str = "HNSW", metric_type: str = "L2", params: Optional[Dict] = None, ): self.dimension = dimension self.shard = shard self.replicas = replicas self.index_type = index_type self.metric_type = metric_type self.params = params
[docs]class TencentVectorDB(VectorStore): """Tencent VectorDB as a vector store. In order to use this you need to have a database instance. See the following documentation for details: https://cloud.tencent.com/document/product/1709/94951 """ field_id: str = "id" field_vector: str = "vector" field_text: str = "text" field_metadata: str = "metadata"
[docs] def __init__( self, embedding: Embeddings, connection_params: ConnectionParams, index_params: IndexParams = IndexParams(128), database_name: str = "LangChainDatabase", collection_name: str = "LangChainCollection", drop_old: Optional[bool] = False, ): self.document = guard_import("tcvectordb.model.document") tcvectordb = guard_import("tcvectordb") self.embedding_func = embedding self.index_params = index_params self.vdb_client = tcvectordb.VectorDBClient( url=connection_params.url, username=connection_params.username, key=connection_params.key, timeout=connection_params.timeout, ) db_list = self.vdb_client.list_databases() db_exist: bool = False for db in db_list: if database_name == db.database_name: db_exist = True break if db_exist: self.database = self.vdb_client.database(database_name) else: self.database = self.vdb_client.create_database(database_name) try: self.collection = self.database.describe_collection(collection_name) if drop_old: self.database.drop_collection(collection_name) self._create_collection(collection_name) except tcvectordb.exceptions.VectorDBException: self._create_collection(collection_name)
def _create_collection(self, collection_name: str) -> None: enum = guard_import("tcvectordb.model.enum") vdb_index = guard_import("tcvectordb.model.index") index_type = None for k, v in enum.IndexType.__members__.items(): if k == self.index_params.index_type: index_type = v if index_type is None: raise ValueError("unsupported index_type") metric_type = None for k, v in enum.MetricType.__members__.items(): if k == self.index_params.metric_type: metric_type = v if metric_type is None: raise ValueError("unsupported metric_type") if self.index_params.params is None: params = vdb_index.HNSWParams(m=16, efconstruction=200) else: params = vdb_index.HNSWParams( m=self.index_params.params.get("M", 16), efconstruction=self.index_params.params.get("efConstruction", 200), ) index = vdb_index.Index( vdb_index.FilterIndex( self.field_id, enum.FieldType.String, enum.IndexType.PRIMARY_KEY ), vdb_index.VectorIndex( self.field_vector, self.index_params.dimension, index_type, metric_type, params, ), vdb_index.FilterIndex( self.field_text, enum.FieldType.String, enum.IndexType.FILTER ), vdb_index.FilterIndex( self.field_metadata, enum.FieldType.String, enum.IndexType.FILTER ), ) self.collection = self.database.create_collection( name=collection_name, shard=self.index_params.shard, replicas=self.index_params.replicas, description="Collection for LangChain", index=index, ) @property def embeddings(self) -> Embeddings: return self.embedding_func
[docs] @classmethod def from_texts( cls, texts: List[str], embedding: Embeddings, metadatas: Optional[List[dict]] = None, connection_params: Optional[ConnectionParams] = None, index_params: Optional[IndexParams] = None, database_name: str = "LangChainDatabase", collection_name: str = "LangChainCollection", drop_old: Optional[bool] = False, **kwargs: Any, ) -> TencentVectorDB: """Create a collection, indexes it with HNSW, and insert data.""" if len(texts) == 0: raise ValueError("texts is empty") if connection_params is None: raise ValueError("connection_params is empty") try: embeddings = embedding.embed_documents(texts[0:1]) except NotImplementedError: embeddings = [embedding.embed_query(texts[0])] dimension = len(embeddings[0]) if index_params is None: index_params = IndexParams(dimension=dimension) else: index_params.dimension = dimension vector_db = cls( embedding=embedding, connection_params=connection_params, index_params=index_params, database_name=database_name, collection_name=collection_name, drop_old=drop_old, ) vector_db.add_texts(texts=texts, metadatas=metadatas) return vector_db
[docs] def add_texts( self, texts: Iterable[str], metadatas: Optional[List[dict]] = None, timeout: Optional[int] = None, batch_size: int = 1000, **kwargs: Any, ) -> List[str]: """Insert text data into TencentVectorDB.""" texts = list(texts) try: embeddings = self.embedding_func.embed_documents(texts) except NotImplementedError: embeddings = [self.embedding_func.embed_query(x) for x in texts] if len(embeddings) == 0: logger.debug("Nothing to insert, skipping.") return [] pks: list[str] = [] total_count = len(embeddings) for start in range(0, total_count, batch_size): # Grab end index docs = [] end = min(start + batch_size, total_count) for id in range(start, end, 1): metadata = "{}" if metadatas is not None: metadata = json.dumps(metadatas[id]) doc = self.document.Document( id="{}-{}-{}".format(time.time_ns(), hash(texts[id]), id), vector=embeddings[id], text=texts[id], metadata=metadata, ) docs.append(doc) pks.append(str(id)) self.collection.upsert(docs, timeout) return pks
[docs] def similarity_search_with_score( self, query: str, k: int = 4, param: Optional[dict] = None, expr: Optional[str] = None, timeout: Optional[int] = None, **kwargs: Any, ) -> List[Tuple[Document, float]]: """Perform a search on a query string and return results with score.""" # Embed the query text. embedding = self.embedding_func.embed_query(query) res = self.similarity_search_with_score_by_vector( embedding=embedding, k=k, param=param, expr=expr, timeout=timeout, **kwargs ) return res
[docs] def similarity_search_by_vector( self, embedding: List[float], k: int = 4, param: Optional[dict] = None, expr: Optional[str] = None, timeout: Optional[int] = None, **kwargs: Any, ) -> List[Document]: """Perform a similarity search against the query string.""" res = self.similarity_search_with_score_by_vector( embedding=embedding, k=k, param=param, expr=expr, timeout=timeout, **kwargs ) return [doc for doc, _ in res]
[docs] def similarity_search_with_score_by_vector( self, embedding: List[float], k: int = 4, param: Optional[dict] = None, expr: Optional[str] = None, timeout: Optional[int] = None, **kwargs: Any, ) -> List[Tuple[Document, float]]: """Perform a search on a query string and return results with score.""" filter = None if expr is None else self.document.Filter(expr) ef = 10 if param is None else param.get("ef", 10) res: List[List[Dict]] = self.collection.search( vectors=[embedding], filter=filter, params=self.document.HNSWSearchParams(ef=ef), retrieve_vector=False, limit=k, timeout=timeout, ) # Organize results. ret: List[Tuple[Document, float]] = [] if res is None or len(res) == 0: return ret for result in res[0]: meta = result.get(self.field_metadata) if meta is not None: meta = json.loads(meta) doc = Document(page_content=result.get(self.field_text), metadata=meta) pair = (doc, result.get("score", 0.0)) ret.append(pair) return ret
[docs] def max_marginal_relevance_search_by_vector( self, embedding: list[float], k: int = 4, fetch_k: int = 20, lambda_mult: float = 0.5, param: Optional[dict] = None, expr: Optional[str] = None, timeout: Optional[int] = None, **kwargs: Any, ) -> List[Document]: """Perform a search and return results that are reordered by MMR.""" filter = None if expr is None else self.document.Filter(expr) ef = 10 if param is None else param.get("ef", 10) res: List[List[Dict]] = self.collection.search( vectors=[embedding], filter=filter, params=self.document.HNSWSearchParams(ef=ef), retrieve_vector=True, limit=fetch_k, timeout=timeout, ) # Organize results. documents = [] ordered_result_embeddings = [] for result in res[0]: meta = result.get(self.field_metadata) if meta is not None: meta = json.loads(meta) doc = Document(page_content=result.get(self.field_text), metadata=meta) documents.append(doc) ordered_result_embeddings.append(result.get(self.field_vector)) # Get the new order of results. new_ordering = maximal_marginal_relevance( np.array(embedding), ordered_result_embeddings, k=k, lambda_mult=lambda_mult ) # Reorder the values and return. ret = [] for x in new_ordering: # Function can return -1 index if x == -1: break else: ret.append(documents[x]) return ret