Hologres

Hologresopen in new window 是由阿里云开发的统一实时数据仓库服务。您可以使用Hologres实时编写、更新、处理和分析大量数据。 Hologres支持标准的SQL语法，与PostgreSQL兼容，并支持大多数PostgreSQL函数。Hologres支持对高达PB级数据进行在线分析处理（OLAP）和即席查询分析，并提供高并发和低延迟的在线数据服务。

Hologres通过采用Proximaopen in new window提供向量数据库功能。 Proxima是阿里巴巴达摩院开发的高性能软件库，它允许您搜索向量的最近邻居。Proxima相比于类似的开源软件如Faiss，提供更高的稳定性和性能。Proxima允许您以高吞吐量和低延迟搜索相似的文本或图像嵌入。Hologres与Proxima深度集成，提供高性能的向量搜索服务。

本文档展示了如何使用与Hologres Proxima向量数据库相关的功能。点击此处open in new window快速部署一个Hologres云实例。

from langchain.embeddings.openai import OpenAIEmbeddings
from langchain.text_splitter import CharacterTextSplitter
from langchain.vectorstores import Hologres

通过调用OpenAI API来拆分文档并获取嵌入向量。

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()

Connect to Hologres by setting related ENVIRONMENTS.

export PG_HOST={host}
export PG_PORT={port} # Optional, default is 80
export PG_DATABASE={db_name} # Optional, default is postgres
export PG_USER={username}
export PG_PASSWORD={password}

然后将您的嵌入向量和文档存储到Hologres中。

import os

connection_string = Hologres.connection_string_from_db_params(
    host=os.environ.get("PGHOST", "localhost"),
    port=int(os.environ.get("PGPORT", "80")),
    database=os.environ.get("PGDATABASE", "postgres"),
    user=os.environ.get("PGUSER", "postgres"),
    password=os.environ.get("PGPASSWORD", "postgres"),
)

vector_db = Hologres.from_documents(
    docs,
    embeddings,
    connection_string=connection_string,
    table_name="langchain_example_embeddings",
)

查询并检索数据。

query = "What did the president say about Ketanji Brown Jackson"
docs = vector_db.similarity_search(query)

print(docs[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.

# Hologres

Hologres