74 lines
1.8 KiB
Markdown
74 lines
1.8 KiB
Markdown
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---
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title: Index Only Fields You Query
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impact: HIGH
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impactDescription: Reduces index size and improves write performance
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tags: rqe, ft.create, index, schema
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description: Index Only Fields You Query
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alwaysApply: true
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---
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## Index Only Fields You Query
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Create indexes with only the fields you need to search, filter, or sort on.
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**Correct:** Index specific fields and use prefixes.
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```
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FT.CREATE idx:products ON HASH PREFIX 1 product:
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SCHEMA
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name TEXT WEIGHT 2.0
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description TEXT
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category TAG SORTABLE
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price NUMERIC SORTABLE
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location GEO
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```
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**Java** (Jedis):
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```java
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import redis.clients.jedis.search.*;
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Schema schema = new Schema()
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.addTextField("name", 1)
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.addTagField("categories");
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// Good: Specify prefix to index only matching keys
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IndexDefinition def = new IndexDefinition(IndexDefinition.Type.HASH)
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.setPrefixes("person:");
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jedis.ftCreate("idx", IndexOptions.defaultOptions().setDefinition(def), schema);
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```
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**Incorrect:** Over-indexing or indexing unused fields.
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```
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# Bad: Indexing every field "just in case"
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FT.CREATE idx:products ON HASH PREFIX 1 product:
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SCHEMA
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name TEXT
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description TEXT
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category TEXT
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subcategory TEXT
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brand TEXT
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sku TEXT
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price NUMERIC
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cost NUMERIC
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margin NUMERIC
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...
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```
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**Java** (Jedis):
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```java
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// Bad: No prefix means all hashes get indexed
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IndexDefinition def = new IndexDefinition(IndexDefinition.Type.HASH);
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// This will index every hash in the database!
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```
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**Tips:**
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- Start with the minimum required fields
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- Add fields as query patterns emerge
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- Use `FT.INFO` to monitor index size
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- Always specify a prefix to avoid indexing unrelated keys
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Reference: [Redis Search Indexing](https://redis.io/docs/latest/develop/interact/search-and-query/indexing/)
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