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Vector Embeddings

Automatic embedding generation for semantic search.

Overview

NornicDB automatically generates vector embeddings for nodes, enabling: - Semantic similarity search - Hybrid search (vector + text) - Automatic relationship inference - Clustering and categorization

Storage model: NornicDB-managed embeddings are stored on nodes in ChunkEmbeddings (the first chunk is the main embedding). Client-managed vectors (e.g. via Qdrant gRPC) are stored in NamedEmbeddings. See docs/architecture/embedding-search.md for details.

Embedding Providers

Provider Latency Cost Quality
Ollama (local) 50-100ms Free High
OpenAI 100-200ms $$$ Highest
Local GGUF 30-80ms Free High

Configuration

# Start Ollama
ollama serve

# Pull embedding model
ollama pull mxbai-embed-large

# Configure NornicDB
export NORNICDB_EMBEDDING_URL=http://localhost:11434
export NORNICDB_EMBEDDING_MODEL=mxbai-embed-large

OpenAI

export NORNICDB_EMBEDDING_PROVIDER=openai
export NORNICDB_EMBEDDING_API_KEY=sk-...
export NORNICDB_EMBEDDING_MODEL=text-embedding-3-small

Local GGUF

export NORNICDB_EMBEDDING_PROVIDER=local
export NORNICDB_EMBEDDING_MODEL_PATH=/models/mxbai-embed-large.gguf
export NORNICDB_EMBEDDING_GPU_LAYERS=-1  # Auto-detect

Which properties are embedded

By default, the embedding worker builds text from all node properties and node labels. Managed embedding metadata is stored internally (EmbedMeta) to avoid property namespace pollution. You can limit this so that only specific properties are used, or exclude others.

Use cases: - Embed only one field (e.g. content) so you don’t re-embed stored vectors or noisy fields. - Exclude internal or large fields (e.g. internal_id, raw_html) from the text sent to the embedder.

YAML (in your config file under embedding_worker):

embedding_worker:
  properties_include: [content]              # Only these keys (empty = all)
  properties_exclude: [internal_id, raw_html]
  include_labels: true                       # Prepend labels (default: true)

Environment variables:

# Embed only the "content" property (and labels)
export NORNICDB_EMBEDDING_PROPERTIES_INCLUDE=content

# Embed only content and title
export NORNICDB_EMBEDDING_PROPERTIES_INCLUDE=content,title

# Exclude internal fields (all other properties still embedded)
export NORNICDB_EMBEDDING_PROPERTIES_EXCLUDE=internal_id,raw_html

# Omit labels from embedding text (e.g. when using a single field)
export NORNICDB_EMBEDDING_INCLUDE_LABELS=false

If properties_include is set, only those keys are used (and exclude still applies). If only properties_exclude is set, all properties except those keys are used. See Configuration Guide for full details.

Automatic Embedding

On Node Creation

When a node is created, embeddings are generated automatically:

node, err := db.CreateNode(ctx, []string{"Document"}, map[string]any{
    "title":   "Machine Learning Basics",
    "content": "An introduction to ML concepts...",
})
// Embedding is generated asynchronously

On Memory Storage

memory := &Memory{
    Content: "User prefers dark mode for coding",
    Title:   "Preference",
}
stored, err := db.Store(ctx, memory)
// Embedding is generated from content + title

Embedding Queue

Embeddings are processed asynchronously for performance:

// Check queue status
status, _ := db.EmbeddingQueueStatus(ctx)
fmt.Printf("Pending: %d\n", status.Pending)
fmt.Printf("Processing: %d\n", status.Processing)

Monitor Queue

curl http://localhost:7474/status | jq .embeddings
{
  "enabled": true,
  "provider": "ollama",
  "model": "mxbai-embed-large",
  "pending": 42,
  "processed_total": 15234,
  "errors": 0
}

Trigger Regeneration

# Regenerate all embeddings
curl -X POST http://localhost:7474/nornicdb/embed/trigger?regenerate=true \
  -H "Authorization: Bearer $TOKEN"

Manual Embedding

Embed Query

// Generate embedding for search query
embedding, err := db.EmbedQuery(ctx, "What are the ML basics?")
if err != nil {
    return err
}

// Use for vector search
results, err := db.HybridSearch(ctx, "", embedding, nil, 10)

Pre-computed Embeddings

// Store with pre-computed embedding
memory := &Memory{
    Content:   "Important information",
    Embedding: precomputedVector, // []float32
}
db.Store(ctx, memory)

Embedding Dimensions

Model Dimensions Memory/Vector
mxbai-embed-large 1024 4KB
text-embedding-3-small 1536 6KB
text-embedding-3-large 3072 12KB

Configuration

export NORNICDB_EMBEDDING_DIMENSIONS=1024

Caching

Embedding Cache

# Cache 10,000 embeddings in memory
export NORNICDB_EMBEDDING_CACHE_SIZE=10000

Cache Behavior

  • Identical text returns cached embedding
  • Cache is LRU (Least Recently Used)
  • Cache is not persisted across restarts

Search with Embeddings

// Pure vector similarity search
results, err := db.FindSimilar(ctx, nodeID, 10)
// Combine vector + text search
results, err := db.HybridSearch(ctx, 
    "machine learning",    // Text query
    queryEmbedding,        // Vector query
    []string{"Document"},  // Labels
    10,                    // Limit
)

RRF Fusion

Results are combined using Reciprocal Rank Fusion:

RRF_score = Σ 1/(k + rank_i)

Where k is typically 60.

Indexing

Vector Index (Auto Strategy)

Embeddings are indexed using an auto-selected strategy:

  • GPU brute-force (exact) when GPU is enabled and N is within the configured threshold
  • CPU brute-force (exact) for small datasets (low overhead)
  • HNSW (ANN) for large datasets when brute-force is no longer viable
// Indexing/search strategy is selected automatically at runtime.
// HNSW parameters (when used) are tuned for quality/speed balance:
//   M: 16
//   efConstruction: 200
//   efSearch: 50

Rebuild Index

curl -X POST http://localhost:7474/admin/rebuild-index \
  -H "Authorization: Bearer $TOKEN"

Best Practices

Content Preparation

// Good: Combine relevant fields
content := fmt.Sprintf("%s\n%s", title, description)
memory := &Memory{Content: content}

// Bad: Too little context
memory := &Memory{Content: "yes"}

Batch Processing

// Process in batches for efficiency
for batch := range batches(nodes, 100) {
    db.CreateNodes(ctx, batch)
    // Wait for embeddings
    time.Sleep(time.Second)
}

Monitor Quality

// Check embedding coverage
result, _ := db.ExecuteCypher(ctx, `
    MATCH (n)
    WHERE n.embedding IS NOT NULL
    RETURN count(n) as with_embedding
`, nil)

Troubleshooting

Embeddings Not Generating

  1. Check embedding service:

    curl http://localhost:11434/api/embed \
      -d '{"model":"mxbai-embed-large","input":"test"}'
    

  2. Check queue:

    curl http://localhost:7474/status | jq .embeddings
    

  3. Check logs:

    docker logs nornicdb | grep -i embed
    

Slow Embedding

  1. Use GPU acceleration
  2. Increase batch size
  3. Use embedding cache
  4. Consider local GGUF models

See Also