Hybrid Search - Upstash Documentation

Full-text search finds documents that contain the words of your query. Semantic search finds documents with a similar meaning, even when they use different words. Hybrid search runs both and merges the results into one list. Hybrid search has two parts:

HYBRID fields are indexed for both full-text and semantic search.
Retrievers run the searches. $ann runs a semantic search, and $rrf merges the results of several retrievers into one list.

Hybrid fields

A HYBRID field is a TEXT field that also stores a vector embedding. Full-text queries work on it the same way as on a TEXT field, and $ann searches its embeddings by meaning. See Hybrid Fields for the field options.

An index can have more than one HYBRID field.
If the text of a document cannot be embedded, the document is still searchable by its text.
HYBRID fields work with JSON, hash, string, and stream indexes.

Create an index

Declare the fields you want to search by meaning as HYBRID:

Redis CLI

SEARCH.CREATE products ON JSON PREFIX 1 product: SCHEMA name TEXT description HYBRID category KEYWORD price F64 FAST

Add documents

Write documents as usual. Search indexes them and creates their embeddings:

Redis CLI

JSON.SET product:1 $ '{"name": "Studio Headphones", "description": "Over-ear headphones with active noise cancelling", "category": "audio", "price": 199}'
JSON.SET product:2 $ '{"name": "Travel Earplugs", "description": "Soft foam earplugs that keep airplane cabin sound out", "category": "travel", "price": 9}'
JSON.SET product:3 $ '{"name": "Sport Earbuds", "description": "Sweat-proof wireless earbuds for running", "category": "sports", "price": 79}'

# Wait until the documents are indexed
SEARCH.WAITINDEXING products

Search by meaning

Use $ann to find the documents that are closest in meaning to a text. This query can find the earplugs, even though their description does not contain the word “noise”:

Redis CLI

SEARCH.QUERY products '{"$ann": {"field": "description", "query": "block noise on a flight"}}'

# Search by meaning within one category
SEARCH.QUERY products '{"$ann": {"field": "description", "query": "headphones for running", "filter": {"category": "sports"}}}'

Combine full-text and semantic search

Use $rrf to run a full-text query and a semantic search, and merge their results into one list. Documents that rank high in both come first:

Redis CLI

SEARCH.QUERY products '{"$rrf": {"retrievers": [{"description": "noise cancelling"}, {"$ann": {"field": "description", "query": "noise cancelling"}}]}}'

To give one side more influence, set its weight. A full-text query takes a weight when you wrap it in $standard:

Redis CLI

SEARCH.QUERY products '{"$rrf": {"retrievers": [{"$standard": {"query": {"description": "noise cancelling"}, "weight": 2}}, {"$ann": {"field": "description", "query": "noise cancelling"}}]}}'

Next steps

See Retrievers for all retriever parameters and rules.
See Schema Definition for field types and options.
See SEARCH.QUERY for all query options.

​Hybrid fields

​Create an index

​Add documents

​Search by meaning

​Combine full-text and semantic search

​Next steps