feat: Add support for generic PGVector vector store (langchain-ai#2657)

* feat: added pgevtor class

* feat: finished pgvector integration

* chore: update create-entrypoints with pgvector vectorstore

* chore: add docs

* nit: final cleanups

* fix: correct metadata type

* fix: allow for optional columns & add defaults

* fix: update doc demo code to new config schema

* chore: lint/format

* Close connections properly

* Small docs fixes

---------

Co-authored-by: jacoblee93 <[email protected]>

.gitignore

@@ -31,4 +31,6 @@ Chinook_Sqlite.sql
 .node-version
 
 firebase-debug.log
-firestore-debug.log
+firestore-debug.log
+
+tmp/

docs/extras/modules/data_connection/vectorstores/integrations/pgvector.mdx

@@ -0,0 +1,35 @@
+# PGVector
+
+To enable vector search in a generic PostgreSQL database, LangChain.js supports using the [`pgvector`](https://github.com/pgvector/pgvector) Postgres extension.
+
+## Setup
+
+To work with PGVector, you need to install the `pg` package:
+
+```bash npm2yarn
+npm install pg
+```
+
+### Setup a `pgvector` self hosted instance with `docker-compose`
+
+`pgvector` provides a prebuilt Docker image that can be used to quickly setup a self-hosted Postgres instance.
+Create a file below named `docker-compose.yml`:
+
+import CodeBlock from "@theme/CodeBlock";
+import DockerExample from "@examples/indexes/vector_stores/pgvector_vectorstore/docker-compose.example.yml";
+
+<CodeBlock language="yml" name="docker-compose.yml">
+  {DockerExample}
+</CodeBlock>
+
+And then in the same directory, run `docker compose up` to start the container.
+
+You can find more information on how to setup `pgvector` in the [official repository](https://github.com/pgvector/pgvector).
+
+## Usage
+
+import Example from "@examples/indexes/vector_stores/pgvector_vectorstore/pgvector.ts";
+
+One complete example of using `PGVectorStore` is the following:
+
+<CodeBlock language="typescript">{Example}</CodeBlock>

examples/package.json

@@ -46,6 +46,7 @@
     "langchain": "workspace:*",
     "ml-distance": "^4.0.0",
     "mongodb": "^5.2.0",
+    "pg": "^8.11.0",
     "pickleparser": "^0.1.0",
     "prisma": "^4.11.0",
     "redis": "^4.6.6",

examples/src/indexes/vector_stores/pgvector_vectorstore/docker-compose.example.yml

@@ -0,0 +1,11 @@
+services:
+  db:
+    image: ankane/pgvector
+    ports:
+      - 5433:5432
+    volumes:
+      - ./data:/var/lib/postgresql/data
+    environment:
+      - POSTGRES_PASSWORD=ChangeMe
+      - POSTGRES_USER=myuser
+      - POSTGRES_DB=api

examples/src/indexes/vector_stores/pgvector_vectorstore/pgvector.ts

@@ -0,0 +1,44 @@
+import { OpenAIEmbeddings } from "langchain/embeddings/openai";
+import { PGVectorStore } from "langchain/vectorstores/pgvector";
+import { PoolConfig } from "pg";
+
+// First, follow set-up instructions at
+// https://js.langchain.com/docs/modules/indexes/vector_stores/integrations/pgvector
+
+const config = {
+  postgresConnectionOptions: {
+    type: "postgres",
+    host: "127.0.0.1",
+    port: 5433,
+    user: "myuser",
+    password: "ChangeMe",
+    database: "api",
+  } as PoolConfig,
+  tableName: "testlangchain",
+  columns: {
+    idColumnName: "id",
+    vectorColumnName: "vector",
+    contentColumnName: "content",
+    metadataColumnName: "metadata",
+  },
+};
+
+const pgvectorStore = await PGVectorStore.initialize(
+  new OpenAIEmbeddings(),
+  config
+);
+
+await pgvectorStore.addDocuments([
+  { pageContent: "what's this", metadata: { a: 2 } },
+  { pageContent: "Cat drinks milk", metadata: { a: 1 } },
+]);
+
+const results = await pgvectorStore.similaritySearch("water", 1);
+
+console.log(results);
+
+/*
+  [ Document { pageContent: 'Cat drinks milk', metadata: { a: 1 } } ]
+*/
+
+await pgvectorStore.end();

langchain/.gitignore

@@ -199,6 +199,9 @@ vectorstores/supabase.d.ts
 vectorstores/opensearch.cjs
 vectorstores/opensearch.js
 vectorstores/opensearch.d.ts
+vectorstores/pgvector.cjs
+vectorstores/pgvector.js
+vectorstores/pgvector.d.ts
 vectorstores/milvus.cjs
 vectorstores/milvus.js
 vectorstores/milvus.d.ts

langchain/package.json

@@ -211,6 +211,9 @@
     "vectorstores/opensearch.cjs",
     "vectorstores/opensearch.js",
     "vectorstores/opensearch.d.ts",
+    "vectorstores/pgvector.cjs",
+    "vectorstores/pgvector.js",
+    "vectorstores/pgvector.d.ts",
     "vectorstores/milvus.cjs",
     "vectorstores/milvus.js",
     "vectorstores/milvus.d.ts",
@@ -1447,6 +1450,11 @@
       "import": "./vectorstores/opensearch.js",
       "require": "./vectorstores/opensearch.cjs"
     },
+    "./vectorstores/pgvector": {
+      "types": "./vectorstores/pgvector.d.ts",
+      "import": "./vectorstores/pgvector.js",
+      "require": "./vectorstores/pgvector.cjs"
+    },
     "./vectorstores/milvus": {
       "types": "./vectorstores/milvus.d.ts",
       "import": "./vectorstores/milvus.js",

langchain/scripts/create-entrypoints.js

@@ -83,6 +83,7 @@ const entrypoints = {
   "vectorstores/qdrant": "vectorstores/qdrant",
   "vectorstores/supabase": "vectorstores/supabase",
   "vectorstores/opensearch": "vectorstores/opensearch",
+  "vectorstores/pgvector": "vectorstores/pgvector",
   "vectorstores/milvus": "vectorstores/milvus",
   "vectorstores/prisma": "vectorstores/prisma",
   "vectorstores/typeorm": "vectorstores/typeorm",
@@ -302,6 +303,7 @@ const requiresOptionalDependency = [
   "vectorstores/qdrant",
   "vectorstores/supabase",
   "vectorstores/opensearch",
+  "vectorstores/pgvector",
   "vectorstores/typeorm",
   "vectorstores/milvus",
   "vectorstores/myscale",

langchain/src/load/import_constants.ts

@@ -46,6 +46,7 @@ export const optionalImportEntrypoints = [
   "langchain/vectorstores/qdrant",
   "langchain/vectorstores/supabase",
   "langchain/vectorstores/opensearch",
+  "langchain/vectorstores/pgvector",
   "langchain/vectorstores/milvus",
   "langchain/vectorstores/typeorm",
   "langchain/vectorstores/myscale",

langchain/src/load/import_type.d.ts

@@ -136,6 +136,9 @@ export interface OptionalImportMap {
   "langchain/vectorstores/opensearch"?:
     | typeof import("../vectorstores/opensearch.js")
     | Promise<typeof import("../vectorstores/opensearch.js")>;
+  "langchain/vectorstores/pgvector"?:
+    | typeof import("../vectorstores/pgvector.js")
+    | Promise<typeof import("../vectorstores/pgvector.js")>;
   "langchain/vectorstores/milvus"?:
     | typeof import("../vectorstores/milvus.js")
     | Promise<typeof import("../vectorstores/milvus.js")>;