langchain/docs/ecosystem/opensearch.md

# OpenSearch

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

## Installation and Setup
- Install the Python package with `pip install opensearch-py`
## Wrappers

### VectorStore

There exists a wrapper around OpenSearch vector databases, allowing you to use it as a vectorstore 
for semantic search using approximate vector search powered by lucene, nmslib and faiss engines 
or using painless scripting and script scoring functions for bruteforce vector search.

To import this vectorstore:
```python
from langchain.vectorstores import OpenSearchVectorSearch
```

For a more detailed walkthrough of the OpenSearch wrapper, see [this notebook](../modules/indexes/vectorstores/examples/opensearch.ipynb)
Add Support for OpenSearch Vector database (#1191) ### Description This PR adds a wrapper which adds support for the OpenSearch vector database. Using opensearch-py client we are ingesting the embeddings of given text into opensearch cluster using Bulk API. We can perform the `similarity_search` on the index using the 3 popular searching methods of OpenSearch k-NN plugin: - `Approximate k-NN Search` use approximate nearest neighbor (ANN) algorithms from the [nmslib](https://github.com/nmslib/nmslib), [faiss](https://github.com/facebookresearch/faiss), and [Lucene](https://lucene.apache.org/) libraries to power k-NN search. - `Script Scoring` extends OpenSearch’s script scoring functionality to execute a brute force, exact k-NN search. - `Painless Scripting` adds the distance functions as painless extensions that can be used in more complex combinations. Also, supports brute force, exact k-NN search like Script Scoring. ### Issues Resolved https://github.com/hwchase17/langchain/issues/1054 --------- Signed-off-by: Naveen Tatikonda <navtat@amazon.com> 1 year ago			`# OpenSearch`

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

			`## Installation and Setup`
			- Install the Python package with `pip install opensearch-py`
			`## Wrappers`

			`### VectorStore`

			`There exists a wrapper around OpenSearch vector databases, allowing you to use it as a vectorstore`
			`for semantic search using approximate vector search powered by lucene, nmslib and faiss engines`
			`or using painless scripting and script scoring functions for bruteforce vector search.`

			`To import this vectorstore:`
			```python
			`from langchain.vectorstores import OpenSearchVectorSearch`
			```

big docs refactor (#1978) Co-authored-by: Ankush Gola <ankush.gola@gmail.com> 1 year ago			`For a more detailed walkthrough of the OpenSearch wrapper, see [this notebook](../modules/indexes/vectorstores/examples/opensearch.ipynb)`