Redis

Redis（远程字典服务器）是一个内存数据结构存储，用作分布式内存键值数据库、缓存和消息代理，可选择性地提供持久性。

本文档展示了如何使用与Redis 向量数据库相关的功能。

安装

!pip install redis

我们希望使用 OpenAIEmbeddings，因此需要获取 OpenAI API 密钥。

import os
import getpass

os.environ['OPENAI_API_KEY'] = getpass.getpass('OpenAI API Key:')

示例

from langchain.embeddings import OpenAIEmbeddings
from langchain.text_splitter import CharacterTextSplitter
from langchain.vectorstores.redis import Redis

from langchain.document_loaders import TextLoader

loader = TextLoader('../../../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()

rds = Redis.from_documents(docs, embeddings, redis_url="redis://localhost:6379",  index_name='link')

rds.index_name

'link'

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

Tonight. I call on the Senate to: Pass the Freedom to Vote Act. Pass the John Lewis Voting Rights Act. And while you’re at it, pass the Disclose Act so Americans can know who is funding our elections. 

Tonight, I’d like to honor someone who has dedicated his life to serve this country: Justice Stephen Breyer—an Army veteran, Constitutional scholar, and retiring Justice of the United States Supreme Court. Justice Breyer, thank you for your service. 

One of the most serious constitutional responsibilities a President has is nominating someone to serve on the United States Supreme Court. 

And I did that 4 days ago, when I nominated Circuit Court of Appeals Judge Ketanji Brown Jackson. One of our nation’s top legal minds, who will continue Justice Breyer’s legacy of excellence.

print(rds.add_texts(["Ankush went to Princeton"]))

['doc:link:d7d02e3faf1b40bbbe29a683ff75b280']

query = "Princeton"
results = rds.similarity_search(query)
print(results[0].page_content)

Ankush went to Princeton

# Load from existing index
rds = Redis.from_existing_index(embeddings, redis_url="redis://localhost:6379", index_name='link')

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

Tonight. I call on the Senate to: Pass the Freedom to Vote Act. Pass the John Lewis Voting Rights Act. And while you’re at it, pass the Disclose Act so Americans can know who is funding our elections. 

Tonight, I’d like to honor someone who has dedicated his life to serve this country: Justice Stephen Breyer—an Army veteran, Constitutional scholar, and retiring Justice of the United States Supreme Court. Justice Breyer, thank you for your service. 

One of the most serious constitutional responsibilities a President has is nominating someone to serve on the United States Supreme Court. 

And I did that 4 days ago, when I nominated Circuit Court of Appeals Judge Ketanji Brown Jackson. One of our nation’s top legal minds, who will continue Justice Breyer’s legacy of excellence.

Redis 作为检索器

这里我们将介绍将向量存储用作检索器的不同选项。

我们可以使用三种不同的搜索方法进行检索。默认情况下，它将使用语义相似性。

retriever = rds.as_retriever()

docs = retriever.get_relevant_documents(query)

我们还可以使用 similarity_limit 作为搜索方法。只有当文档足够相似时，才返回结果。

retriever = rds.as_retriever(search_type="similarity_limit")

# 这里我们可以看到它没有返回任何结果，因为没有相关的文档
retriever.get_relevant_documents("where did ankush go to college?")