Performing Faceted Search with Redis Cloud Databases – Redis Knowledge Base

Faceted search in Redis Cloud enables real-time filtering and grouping of search results by attributes such as category, brand, and color, making it well suited for catalogs, analytics, and search-driven UIs. Redis Cloud implements faceted search through the Redis Search module, which provides synchronous indexing and fast aggregations with FT.SEARCH and FT.AGGREGATE.
This article explains how faceted search works in Redis Cloud, provides example schemas and queries for common patterns, and includes troubleshooting guidance for index, schema, and aggregation issues.

Quick Fix Table

Symptom	Likely Cause	Recommended Action
Aggregation counts missing or incorrect	Schema mismatch or unindexed data	Run `FT.INFO <index>` and check for `hash_indexing_failures`
No results returned for facet filter	Field not defined as TAG	Redefine field as TAG; TEXT fields cannot be filtered
Performance slow for large datasets	Too many unfiltered results	Use `SORTBY` and `LIMIT` in aggregation queries
`FT.AGGREGATE` not recognized	Module unavailable or disabled	Verify Redis Cloud plan includes Redis Search
Unexpected facet groupings	Multi-value field not split	Use `APPLY "split(@field)" AS field` before `GROUPBY`

Implementing Faceted Search in Redis Cloud

Faceted search is implemented using TAG fields in a Redis Search index and aggregation queries to group and count documents by facet.

Example

Create Index

FT.CREATE product_idx ON JSON PREFIX 1 product: SCHEMA \
  $.Name AS name TEXT \
  $.Brand AS brand TAG SORTABLE \
  $.Color AS color TAG SORTABLE

Insert Data

JSON.SET product:1 $ '{"Name":"Classic loafers", "Brand":"Santoni", "Color":"brown"}'
JSON.SET product:2 $ '{"Name":"Running shoes", "Brand":"Adidas", "Color":"black"}'

Get Document Count per Facet

FT.AGGREGATE product_idx * GROUPBY 1 @color REDUCE COUNT 0 AS num SORTBY 2 @num DESC

Filter by Facet

FT.SEARCH product_idx '@color:{brown}' RETURN 2 name brand

Combine Full-text and Facet Filters

FT.SEARCH product_idx 'leather @brand:{Santoni}'

Troubleshooting Common Issues

Issue	Cause	Resolution
Facet counts missing	Index not fully built	Wait until `FT.INFO` shows `indexing: 0`
Aggregation returns duplicates	Multi-value fields not split	Add `APPLY "split(@field)" AS field` before `GROUPBY`
Facet filter returns no data	Field type TEXT instead of TAG	Use TAG for all facet fields
Search is extremely slow	No `LIMIT` or selective grouping	Add `LIMIT` and selective filters
Module unavailable	Search module not included in plan	Upgrade to Redis Cloud Pro or above

FAQs

Can I use JSON documents for faceted search in Redis Cloud?
Yes. Redis Search supports both Hashes and JSON documents via the ON JSON schema option.

Can I combine faceted filters and full-text search?
Yes. You can combine textual search terms and facet filters in a single FT.SEARCH query.

Are aggregations real-time?
Yes. Redis recalculates aggregations on each query, allowing real-time facet updates.

Related to