> ## Documentation Index
> Fetch the complete documentation index at: https://docs.agentfront.dev/llms.txt
> Use this file to discover all available pages before exploring further.

# HNSW Tuning

> Tune HNSW parameters for your specific use case

Learn how to tune HNSW parameters for different scenarios.

## Tuning Guidelines

### For Real-Time Search Applications

Prioritize low latency over maximum recall:

```ts title="src/hnsw-realtime.ts" theme={"theme":{"light":"snazzy-light","dark":"dark-plus"}}
const realtime = new VectoriaDB({
  useHNSW: true,
  hnsw: {
    M: 16,
    efConstruction: 200,
    efSearch: 40, // Low for speed
  },
});
```

### For High-Precision Applications

Prioritize accuracy over speed:

```ts title="src/hnsw-precision.ts" theme={"theme":{"light":"snazzy-light","dark":"dark-plus"}}
const precision = new VectoriaDB({
  useHNSW: true,
  hnsw: {
    M: 24,
    efConstruction: 400,
    efSearch: 200, // High for accuracy
  },
});
```

### For Memory-Constrained Environments

Minimize memory footprint:

```ts title="src/hnsw-low-memory.ts" theme={"theme":{"light":"snazzy-light","dark":"dark-plus"}}
const lowMemory = new VectoriaDB({
  useHNSW: true,
  hnsw: {
    M: 8,  // Lower M uses less memory
    efConstruction: 100,
    efSearch: 30,
  },
});
```

## Dynamic efSearch

Adjust efSearch per-query based on requirements:

```ts title="src/dynamic-ef-search.ts" theme={"theme":{"light":"snazzy-light","dark":"dark-plus"}}
async function search(query: string, precision: 'low' | 'medium' | 'high') {
  const efSearch = {
    low: 20,
    medium: 50,
    high: 200,
  }[precision];

  return db.search(query, {
    topK: 10,
    efSearch,
  });
}

// Fast search for autocomplete
const suggestions = await search(input, 'low');

// High-precision search for final results
const results = await search(query, 'high');
```

## Recall vs Speed Trade-offs

```
            Recall
              ^
        99% --|------------------o Quality
              |                /
        97% --|------------o Balanced
              |          /
        95% --|------o Speed
              |    /
        93% --|--o Fast
              |
              +----+----+----+----+---> Speed
                  1ms  2ms  5ms  10ms
```

## Benchmarking Your Configuration

```ts title="src/benchmark.ts" theme={"theme":{"light":"snazzy-light","dark":"dark-plus"}}
async function benchmarkHNSW(config: HNSWConfig) {
  const db = new VectoriaDB({ useHNSW: true, hnsw: config });
  await db.initialize();

  // Build benchmark
  const buildStart = Date.now();
  await db.addMany(documents);
  const buildTime = Date.now() - buildStart;

  // Search benchmark
  const searchTimes: number[] = [];
  for (const query of testQueries) {
    const start = Date.now();
    await db.search(query);
    searchTimes.push(Date.now() - start);
  }

  const avgSearchTime = searchTimes.reduce((a, b) => a + b) / searchTimes.length;

  return { buildTime, avgSearchTime };
}
```

## Common Issues

### Poor Recall

If results aren't relevant enough:

1. Increase `efSearch` for search-time improvement
2. Increase `M` and `efConstruction`, then rebuild index

### Slow Search

If search is too slow:

1. Decrease `efSearch`
2. Consider lower `M` if memory allows

### Slow Indexing

If bulk indexing is too slow:

1. Decrease `efConstruction`
2. Consider building without HNSW, then enabling it

## Recommended Starting Points

| Use Case       | M  | efConstruction | efSearch |
| -------------- | -- | -------------- | -------- |
| Autocomplete   | 12 | 100            | 20       |
| General search | 16 | 200            | 50       |
| High-precision | 24 | 400            | 100      |
| Maximum recall | 32 | 400            | 200      |

## Related

<CardGroup cols={3}>
  <Card title="HNSW Overview" icon="chart-network" href="/vectoriadb/guides/scaling/hnsw-overview">
    Introduction to HNSW
  </Card>

  <Card title="HNSW Configuration" icon="gear" href="/vectoriadb/guides/scaling/hnsw-configuration">
    Parameter reference
  </Card>

  <Card title="Search Performance" icon="gauge" href="/vectoriadb/guides/search/performance">
    General performance tips
  </Card>
</CardGroup>