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Tair 是由 阿里云 开发的云原生内存数据库服务。它提供丰富的数据模型和企业级能力,在完全兼容开源 Redis 的同时支持实时在线场景。Tair 还引入了基于新型非易失性内存(NVM)存储介质的持久内存优化实例。
本笔记本演示如何使用 Tair 向量数据库的相关功能。 使用此集成需要先通过 pip install -qU langchain-community 安装 langchain-community 运行前,请确保已有一个正在运行的 Tair 实例。
from langchain_community.embeddings.fake import FakeEmbeddings
from langchain_community.vectorstores import Tair
from langchain_text_splitters import CharacterTextSplitter
from langchain_community.document_loaders import TextLoader

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 = FakeEmbeddings(size=128)
使用 TAIR_URL 环境变量连接到 Tair
export TAIR_URL="redis://{username}:{password}@{tair_address}:{tair_port}"
或使用关键字参数 tair_url 然后将文档和嵌入存储到 Tair 中。
tair_url = "redis://localhost:6379"

# drop first if index already exists
Tair.drop_index(tair_url=tair_url)

vector_store = Tair.from_documents(docs, embeddings, tair_url=tair_url)
查询相似文档。
query = "What did the president say about Ketanji Brown Jackson"
docs = vector_store.similarity_search(query)
docs[0]
Tair 混合搜索索引构建
# drop first if index already exists
Tair.drop_index(tair_url=tair_url)

vector_store = Tair.from_documents(
    docs, embeddings, tair_url=tair_url, index_params={"lexical_algorithm": "bm25"}
)
Tair 混合搜索
query = "What did the president say about Ketanji Brown Jackson"
# hybrid_ratio: 0.5 hybrid search, 0.9999 vector search, 0.0001 text search
kwargs = {"TEXT": query, "hybrid_ratio": 0.5}
docs = vector_store.similarity_search(query, **kwargs)
docs[0]