This page covers how to use the Postgres PGVector ecosystem within LangChain It is broken into two parts: installation and setup, and then references to specific PGVector wrappers.

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Installation

  • Install the Python package with pip install pgvector

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Setup

  1. The first step is to create a database with the pgvector extension installed. Follow the steps at PGVector Installation Steps to install the database and the extension. The docker image is the easiest way to get started.

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Wrappers

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VectorStore

There exists a wrapper around Postgres vector databases, allowing you to use it as a vectorstore, whether for semantic search or example selection. To import this vectorstore: 
from langchain_community.vectorstores.pgvector import PGVector

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Usage

For a more detailed walkthrough of the PGVector Wrapper, see this notebook