Index Creation and Management

Introduction to Index Creation

Redis OM Spring automates the creation and management of Redis Query Engine indices based on your entity annotations. As of Redis 8, the Query Engine is a standard component of Redis. The process involves:

Entity annotations (@Document, @Indexed, etc.) define the structure
Index creation process generates appropriate Redis Query Engine indices
Different creation modes control how indices are managed

Benefits include fast queries, full-text search, numeric range queries, geospatial search, and vector similarity search.

Index Creation Process

Automatic Index Creation

When your application starts, Redis OM Spring scans for annotated entity classes and creates the necessary indices:

@Document(indexName = "product-idx")
public class Product {
    @Id
    private String id;

    @TextIndexed
    private String name;

    @TextIndexed(weight = 0.5)
    private String description;

    @NumericIndexed
    private double price;

    @TagIndexed
    private List<String> categories;

    // Other fields, getters, setters
}

Based on these annotations, Redis OM Spring will create a Redis Query Engine index named product-idx with appropriate field definitions.

Index Creation Modes

Control how indices are created using the indexCreationMode attribute:

@Document(indexName = "product-idx", indexCreationMode = IndexCreationMode.RECREATE_INDEXES)
public class Product {
    // Fields
}

Available modes:

CREATE_IF_NOT_EXIST (default) - Only create the index if it doesn’t exist
RECREATE_INDEXES - Drop and recreate the index on application startup
NO_CREATE_NO_DROP - Don’t create or drop indices (manual management)

The index creation process varies based on the selected mode:

With CREATE_IF_NOT_EXIST (default):
- Redis OM Spring checks if the index already exists
- If it doesn’t exist, creates the index
- If it exists, skips creation
With RECREATE_INDEXES:
- Drops the index if it exists
- Creates a new index
With NO_CREATE_NO_DROP:
- Skips all index operations

Advanced Index Configuration

@IndexingOptions

The @IndexingOptions annotation provides advanced configuration for your indices:

@Document
@IndexingOptions(
    stopWords = {"a", "an", "the", "in", "on", "at"},
    language = "English",
    prefixes = {"product:"}
)
public class Product {
    // Fields
}

Configuration options:

stopWords - Words to ignore in text searches
language - Default language for stemming (e.g., "English", "French", "German")
prefixes - Key prefixes to include in the index
filter - Custom filtering expression for the index
maxTextFields - Whether to index all text fields
temporaryIndex - Create a temporary index that will be deleted when the connection closes

Field-Level Configuration

Configure individual fields with specific indexing options:

@Document
public class Article {
    @Id
    private String id;

    @TextIndexed(sortable = true, weight = 1.5, nostem = true)
    private String title;

    @TextIndexed(weight = 1.0)
    private String content;

    @TextIndexed(phonetic = "dm:en")
    private String authorName;

    // Other fields
}

Manual Index Management

Programmatic Index Creation

For advanced cases, you can manage indices programmatically using the RediSearchIndexer class:

@Service
public class IndexService {

    @Autowired
    private RediSearchIndexer indexer;

    public void recreateIndex(Class<?> entityClass) {
        // Drop the existing index and documents for the entity
        indexer.dropIndexAndDocumentsFor(entityClass);

        // Create a new index for the entity
        indexer.createIndexFor(entityClass);
    }
}

Redis CLI Commands

You can also manage indices directly using the Redis CLI:

# List all indices
FT._LIST

# Get index info
FT.INFO product-idx

# Drop an index
FT.DROPINDEX product-idx

Best Practices

Choose the appropriate index creation mode for your environment
Use CREATE_IF_NOT_EXIST for production to avoid disruption
Use RECREATE_INDEXES during development for schema changes
Configure language settings for proper text searching
Define appropriate stop words for your domain
Consider index size and memory usage
Be careful with sortable fields as they increase memory usage