Hologres

Hologres 是由阿里云开发的统一实时数据仓库服务。您可以使用 Hologres 实时写入、更新、处理和分析大量数据。Hologres 支持标准 SQL 语法，兼容 PostgreSQL，并支持大多数 PostgreSQL 函数。Hologres 支持高达 PB 级别的在线分析处理（OLAP）和即席分析，并提供高并发和低延迟的在线数据服务。

Hologres 通过采用 Proxima 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 提供比 Faiss 等类似开源软件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。

本笔记本展示了如何使用与 Hologres Proxima 向量数据库相关的功能。

点击这里快速部署 Hologres 云实例。

%pip install --upgrade --quiet  hologres-vector

from langchain_community.vectorstores import Hologres
from langchain_openai import OpenAIEmbeddings
from langchain_text_splitters import CharacterTextSplitter

通过调用 OpenAI API 分割文档并获取嵌入

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 = OpenAIEmbeddings()

通过设置相关环境变量连接到 Hologres

export PG_HOST={host}
export PG_PORT={port} # 可选，默认为 80
export PG_DATABASE={db_name} # 可选，默认为 postgres
export PG_USER={username}
export PG_PASSWORD={password}

然后将您的嵌入和文档存储到 Hologres

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",
)

查询和检索数据

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.