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Typesense 是一个开源的内存搜索引擎,您可以选择自托管或在 Typesense Cloud 上运行。 Typesense 通过将整个索引存储在 RAM 中(同时在磁盘上进行备份)来专注于性能,并通过简化可用选项和设置合理的默认值来提供开箱即用的开发者体验。 它还允许您将基于属性的过滤与向量查询相结合,以获取最相关的文档。
本 notebook 将展示如何将 Typesense 用作您的 VectorStore。 首先安装依赖项:
pip install -qU  typesense openapi-schema-pydantic langchain-openai langchain-community tiktoken
我们希望使用 OpenAIEmbeddings,因此需要获取 OpenAI API Key。
import getpass
import os

if "OPENAI_API_KEY" not in os.environ:
    os.environ["OPENAI_API_KEY"] = getpass.getpass("OpenAI API Key:")
from langchain_community.document_loaders import TextLoader
from langchain_community.vectorstores import Typesense
from langchain_openai import OpenAIEmbeddings
from langchain_text_splitters import CharacterTextSplitter
导入测试数据集:
loader = TextLoader("../../how_to/state_of_the_union.txt")
documents = loader.load()
text_splitter = CharacterTextSplitter(chunk_size=1000, chunk_overlap=0)
docs = text_splitter.split_documents(documents)

embeddings = OpenAIEmbeddings()
docsearch = Typesense.from_documents(
    docs,
    embeddings,
    typesense_client_params={
        "host": "localhost",  # Use xxx.a1.typesense.net for Typesense Cloud
        "port": "8108",  # Use 443 for Typesense Cloud
        "protocol": "http",  # Use https for Typesense Cloud
        "typesense_api_key": "xyz",
        "typesense_collection_name": "lang-chain",
    },
)

相似性搜索

query = "What did the president say about Ketanji Brown Jackson"
found_docs = docsearch.similarity_search(query)
print(found_docs[0].page_content)

将 Typesense 用作检索器

与所有其他向量存储一样,Typesense 是一个 LangChain 检索器,使用余弦相似度进行检索。
retriever = docsearch.as_retriever()
retriever
query = "What did the president say about Ketanji Brown Jackson"
retriever.invoke(query)[0]