# RAG - Timescale - hybrid search

This template shows how to use `Timescale Vector` with the self-query retriever to perform hybrid search on similarity and time.

This is useful any time your data has a strong time-based component. Some examples of such data are:
- News articles (politics, business, etc)
- Blog posts, documentation or other published material (public or private).
- Social media posts
- Changelogs of any kind
- Messages

Such items are often searched by both similarity and time. For example: Show me all news about Toyota trucks from 2022.

[Timescale Vector](https://www.timescale.com/ai?utm_campaign=vectorlaunch&utm_source=langchain&utm_medium=referral)  provides superior performance when searching for embeddings within a particular timeframe by leveraging automatic table partitioning to isolate data for particular time-ranges.

Langchain's self-query retriever allows deducing time-ranges (as well as other search criteria) from the text of user queries.

## What is Timescale Vector?

**[Timescale Vector](https://www.timescale.com/ai?utm_campaign=vectorlaunch&utm_source=langchain&utm_medium=referral) is PostgreSQL++ for AI applications.**

Timescale Vector enables you to efficiently store and query billions of vector embeddings in `PostgreSQL`.
- Enhances `pgvector` with faster and more accurate similarity search on 1B+ vectors via DiskANN inspired indexing algorithm.
- Enables fast time-based vector search via automatic time-based partitioning and indexing.
- Provides a familiar SQL interface for querying vector embeddings and relational data.

Timescale Vector is cloud PostgreSQL for AI that scales with you from POC to production:
- Simplifies operations by enabling you to store relational metadata, vector embeddings, and time-series data in a single database.
- Benefits from rock-solid PostgreSQL foundation with enterprise-grade feature liked streaming backups and replication, high-availability and row-level security.
- Enables a worry-free experience with enterprise-grade security and compliance.

### How to access Timescale Vector
Timescale Vector is available on [Timescale](https://www.timescale.com/products?utm_campaign=vectorlaunch&utm_source=langchain&utm_medium=referral), the cloud PostgreSQL platform. (There is no self-hosted version at this time.)

- LangChain users get a 90-day free trial for Timescale Vector.
- To get started, [signup](https://console.cloud.timescale.com/signup?utm_campaign=vectorlaunch&utm_source=langchain&utm_medium=referral) to Timescale, create a new database and follow this notebook!
- See the [installation instructions](https://github.com/timescale/python-vector) for more details on using Timescale Vector in python.

## Environment Setup

This template uses Timescale Vector as a vectorstore and requires that `TIMESCALES_SERVICE_URL`. Signup for a 90-day trial [here](https://console.cloud.timescale.com/signup?utm_campaign=vectorlaunch&utm_source=langchain&utm_medium=referral) if you don't yet have an account.

To load the sample dataset, set `LOAD_SAMPLE_DATA=1`. To load your own dataset see the section below.

Set the `OPENAI_API_KEY` environment variable to access the OpenAI models.

## Usage

To use this package, you should first have the LangChain CLI installed:

```shell
pip install -U langchain-cli
```

To create a new LangChain project and install this as the only package, you can do:

```shell
langchain app new my-app --package rag-timescale-hybrid-search-time
```

If you want to add this to an existing project, you can just run:

```shell
langchain app add rag-timescale-hybrid-search-time
```

And add the following code to your `server.py` file:
```python
from rag_timescale_hybrid_search.chain import chain as rag_timescale_hybrid_search_chain

add_routes(app, rag_timescale_hybrid_search_chain, path="/rag-timescale-hybrid-search")
```

(Optional) Let's now configure LangSmith.
LangSmith will help us trace, monitor and debug LangChain applications.
You can sign up for LangSmith [here](https://smith.langchain.com/).
If you don't have access, you can skip this section

```shell
export LANGCHAIN_TRACING_V2=true
export LANGCHAIN_API_KEY=<your-api-key>
export LANGCHAIN_PROJECT=<your-project>  # if not specified, defaults to "default"
```

If you are inside this directory, then you can spin up a LangServe instance directly by:

```shell
langchain serve
```

This will start the FastAPI app with a server is running locally at
[http://localhost:8000](http://localhost:8000)

We can see all templates at [http://127.0.0.1:8000/docs](http://127.0.0.1:8000/docs)
We can access the playground at [http://127.0.0.1:8000/rag-timescale-hybrid-search/playground](http://127.0.0.1:8000/rag-timescale-hybrid-search/playground)

We can access the template from code with:

```python
from langserve.client import RemoteRunnable

runnable = RemoteRunnable("http://localhost:8000/rag-timescale-hybrid-search")
```

## Loading your own dataset

To load your own dataset you will have to modify the code in the `DATASET SPECIFIC CODE` section of `chain.py`.
This code defines the name of the collection, how to load the data, and the human-language description of both the
contents of the collection and all of the metadata. The human-language descriptions are used by the self-query retriever
to help the LLM convert the question into filters on the metadata when searching the data in Timescale-vector.