skills/redis-development/rules/rqe-index-creation.md

title	impact	impactDescription	tags	description	alwaysApply
Index Only Fields You Query	HIGH	Reduces index size and improves write performance	rqe, ft.create, index, schema	Index Only Fields You Query	true

Index Only Fields You Query

Create indexes with only the fields you need to search, filter, or sort on.

Correct: Index specific fields and use prefixes.

FT.CREATE idx:products ON HASH PREFIX 1 product:
    SCHEMA
        name TEXT WEIGHT 2.0
        description TEXT
        category TAG SORTABLE
        price NUMERIC SORTABLE
        location GEO

Java (Jedis):

import redis.clients.jedis.search.*;

Schema schema = new Schema()
    .addTextField("name", 1)
    .addTagField("categories");

// Good: Specify prefix to index only matching keys
IndexDefinition def = new IndexDefinition(IndexDefinition.Type.HASH)
    .setPrefixes("person:");

jedis.ftCreate("idx", IndexOptions.defaultOptions().setDefinition(def), schema);

Incorrect: Over-indexing or indexing unused fields.

# Bad: Indexing every field "just in case"
FT.CREATE idx:products ON HASH PREFIX 1 product:
    SCHEMA
        name TEXT
        description TEXT
        category TEXT
        subcategory TEXT
        brand TEXT
        sku TEXT
        price NUMERIC
        cost NUMERIC
        margin NUMERIC
        ...

Java (Jedis):

// Bad: No prefix means all hashes get indexed
IndexDefinition def = new IndexDefinition(IndexDefinition.Type.HASH);
// This will index every hash in the database!

Tips:

• Start with the minimum required fields
• Add fields as query patterns emerge
• Use FT.INFO to monitor index size
• Always specify a prefix to avoid indexing unrelated keys

Reference: Redis Search Indexing