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Redis

Redis (Remote Dictionary Server) is an in-memory data structure store, used as a distributed, in-memory key–value database, cache and message broker, with optional durability.

This notebook shows how to use functionality related to the Redis vector database.

As database either Redis standalone server or Redis Sentinel HA setups are supported for connections with the "redis_url" parameter. More information about the different formats of the redis connection url can be found in the LangChain Redis Readme file

Installing​

pip install redis

We want to use OpenAIEmbeddings so we have to get the OpenAI API Key.

import os
import getpass

os.environ["OPENAI_API_KEY"] = getpass.getpass("OpenAI API Key:")

Example​

from langchain.embeddings import OpenAIEmbeddings
from langchain.text_splitter import CharacterTextSplitter
from langchain.vectorstores.redis import Redis

API Reference:

from langchain.document_loaders import TextLoader

loader = TextLoader("../../../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()

API Reference:

If you're not interested in the keys of your entries you can also create your redis instance from the documents.

rds = Redis.from_documents(
    docs, embeddings, redis_url="redis://localhost:6379", index_name="link"
)

If you're interested in the keys of your entries you have to split your docs in texts and metadatas

texts = [d.page_content for d in docs]
metadatas = [d.metadata for d in docs]

rds, keys = Redis.from_texts_return_keys(
    texts, embeddings, redis_url="redis://localhost:6379", index_name="link"
)
rds.index_name
query = "What did the president say about Ketanji Brown Jackson"
results = rds.similarity_search(query)
print(results[0].page_content)
print(rds.add_texts(["Ankush went to Princeton"]))
query = "Princeton"
results = rds.similarity_search(query)
print(results[0].page_content)
# Load from existing index
rds = Redis.from_existing_index(
    embeddings, redis_url="redis://localhost:6379", index_name="link"
)

query = "What did the president say about Ketanji Brown Jackson"
results = rds.similarity_search(query)
print(results[0].page_content)

Redis as Retriever​

Here we go over different options for using the vector store as a retriever.

There are three different search methods we can use to do retrieval. By default, it will use semantic similarity.

retriever = rds.as_retriever()
docs = retriever.get_relevant_documents(query)

We can also use similarity_limit as a search method. This is only return documents if they are similar enough

retriever = rds.as_retriever(search_type="similarity_limit")
# Here we can see it doesn't return any results because there are no relevant documents
retriever.get_relevant_documents("where did ankush go to college?")

Delete keys

To delete your entries you have to address them by their keys.

Redis.delete(keys, redis_url="redis://localhost:6379")

Redis connection Url examples​

Valid Redis Url scheme are:

  1. redis:// - Connection to Redis standalone, unencrypted
  2. rediss:// - Connection to Redis standalone, with TLS encryption
  3. redis+sentinel:// - Connection to Redis server via Redis Sentinel, unencrypted
  4. rediss+sentinel:// - Connection to Redis server via Redis Sentinel, booth connections with TLS encryption

More information about additional connection parameter can be found in the redis-py documentation at https://redis-py.readthedocs.io/en/stable/connections.html

# connection to redis standalone at localhost, db 0, no password
redis_url = "redis://localhost:6379"
# connection to host "redis" port 7379 with db 2 and password "secret" (old style authentication scheme without username / pre 6.x)
redis_url = "redis://:secret@redis:7379/2"
# connection to host redis on default port with user "joe", pass "secret" using redis version 6+ ACLs
redis_url = "redis://joe:secret@redis/0"

# connection to sentinel at localhost with default group mymaster and db 0, no password
redis_url = "redis+sentinel://localhost:26379"
# connection to sentinel at host redis with default port 26379 and user "joe" with password "secret" with default group mymaster and db 0
redis_url = "redis+sentinel://joe:secret@redis"
# connection to sentinel, no auth with sentinel monitoring group "zone-1" and database 2
redis_url = "redis+sentinel://redis:26379/zone-1/2"

# connection to redis standalone at localhost, db 0, no password but with TLS support
redis_url = "rediss://localhost:6379"
# connection to redis sentinel at localhost and default port, db 0, no password
# but with TLS support for booth Sentinel and Redis server
redis_url = "rediss+sentinel://localhost"