brainy/docs/BATCHING.md

---
title: Batch Operations
slug: guides/batching
public: true
category: guides
template: guide
order: 5
description: Eliminate N+1 query patterns with batchGet() and storage-level batch APIs for fast multi-entity reads against filesystem and memory storage.
next:
  - api/reference
  - guides/find-system
---

# Batch Operations API
> **Production-Ready** | Zero N+1 Query Patterns

## Overview

Brainy provides batch operations at the storage layer to eliminate N+1 query patterns for VFS operations, relationship queries, and entity retrieval.

### Problem Solved

The naive pattern of looping and calling `brain.get(id)` once per item issues sequential reads through the storage layer. Batched APIs collapse that into a single read pass.

**IMPORTANT:** The batch optimizations apply **ONLY to `getTreeStructure()`** at the VFS layer and the explicit `batchGet()` / `getNounMetadataBatch()` calls — not to `readFile()` or individual `get()` operations.

---

## New Public APIs

### 1. `brain.batchGet(ids, options?)`

Batch retrieval of multiple entities (metadata-only by default).

```typescript
// Fetch multiple entities in a single batched operation
const ids = ['id1', 'id2', 'id3']
const results: Map<string, Entity> = await brain.batchGet(ids)

// With vectors (falls back to individual gets)
const resultsWithVectors = await brain.batchGet(ids, { includeVectors: true })

// Results map
results.get('id1') // → Entity or undefined
results.size // → 3 (number of found entities)
```

**Performance:**
- Memory storage: Instant (parallel reads)
- Filesystem storage: Parallel reads, scales with available IOPS

**Use Cases:**
- Loading multiple entities for display
- Bulk data export operations
- Relationship traversal (fetch all connected entities)

---

## Storage-Level APIs

### 2. `storage.getNounMetadataBatch(ids)`

Batch metadata retrieval with direct O(1) path construction.

```typescript
const storage = brain.storage as BaseStorage
const ids = ['id1', 'id2', 'id3']

const metadataMap: Map<string, NounMetadata> = await storage.getNounMetadataBatch(ids)

for (const [id, metadata] of metadataMap) {
 console.log(metadata.noun) // Type: 'document', 'person', etc.
 console.log(metadata.data) // Entity data
}
```

**Features:**
- ✅ Direct O(1) path construction from ID (no type lookup needed!)
- ✅ Sharding preservation (all paths include `{shard}/{id}`)
- ✅ COW-aware (respects branch paths)
- ✅ 40x faster than v5.x type-first architecture

**Performance:**
- ~1ms per 100 entities (consistent, no cache misses!)
- Filesystem: parallel reads bounded by IOPS
- No type search delays — every ID maps directly to storage path

---

### 3. `storage.getVerbsBySourceBatch(sourceIds, verbType?)`

Batch relationship queries by source entity IDs.

```typescript
const storage = brain.storage as BaseStorage

// Get all relationships from multiple sources
const results: Map<string, GraphVerb[]> = await storage.getVerbsBySourceBatch([
 'person1',
 'person2'
])

// Filter by verb type
const createsResults = await storage.getVerbsBySourceBatch(
 ['person1', 'person2'],
 'creates'
)

// Process results
for (const [sourceId, verbs] of results) {
 console.log(`${sourceId} has ${verbs.length} relationships`)
 verbs.forEach(verb => {
 console.log(` → ${verb.verb} → ${verb.targetId}`)
 })
}
```

**Use Cases:**
- Social graph traversal (fetch all connections for multiple users)
- Knowledge graph queries (find all relationships of specific type)
- Bulk export of relationship data

**Performance:**
- Memory storage: <10ms for 1000 relationships
- Filesystem storage: parallel reads through the metadata index

---

### 4. `storage.readBatchWithInheritance(paths, targetBranch?)`

COW-aware batch path resolution with branch inheritance.

```typescript
const storage = brain.storage as BaseStorage

const paths = [
 'entities/nouns/{shard}/id1/metadata.json',
 'entities/nouns/{shard}/id2/metadata.json'
]

// Resolves to: branches/{branch}/entities/nouns/{shard}/{id}/metadata.json
const results: Map<string, any> = await storage.readBatchWithInheritance(paths, 'my-branch')

// Automatically inherits from parent branches for missing entities
```

**Features:**
- ✅ Branch path resolution (`branches/{branch}/...`)
- ✅ Write cache integration (read-after-write consistency)
- ✅ COW inheritance (fallback to parent commits for missing entities)
- ✅ Adapter-agnostic (works with all storage adapters)

---

## VFS Integration

VFS operations automatically use batch APIs for maximum performance.

### Directory Traversal

```typescript
// Tree traversal uses batched reads under the hood
const tree = await brain.vfs.getTreeStructure('/my-dir')
// ✅ PathResolver.getChildren() uses brain.batchGet() internally
// ✅ Parallel traversal of directories at the same tree level
// ✅ 2-3 batched calls instead of 22 sequential calls
```

**Architecture:**

```
VFS.getTreeStructure()
 ↓ PARALLEL (breadth-first traversal)
 → PathResolver.getChildren() [all dirs at level processed in parallel]
 ↓ BATCHED
 → brain.batchGet(childIds) [1 call instead of N]
 ↓ BATCHED
 → storage.getNounMetadataBatch(ids) [1 call instead of N]
 ↓ ADAPTER
 → Filesystem: Promise.all() parallel reads
 → Memory: Promise.all() parallel reads
```

---

## Advanced Features Compatibility

### ✅ ID-First Storage Architecture

All batch operations use direct ID-first paths - no type lookup needed!

**ID-First Path Structure:**
```
entities/nouns/{SHARD}/{ID}/metadata.json
entities/verbs/{SHARD}/{ID}/metadata.json
```

**Direct O(1) Path Construction:**
```typescript
// Every ID maps directly to exactly ONE path - 40x faster!
const id = 'abc-123'
const shard = getShardIdFromUuid(id) // → 'ab' (first 2 hex chars)
const path = `entities/nouns/${shard}/${id}/metadata.json`

// No type cache needed!
// No type search needed!
// No multi-type fallback needed!
// Just pure O(1) lookup!
```

**Benefits:**
- **40x faster** path lookups (eliminates 42-type sequential search)
- **Simpler code** - removed 500+ lines of type cache complexity
- **Scalable** - works at billion-scale without type tracking overhead

---

### ✅ Sharding

All batch paths include shard IDs calculated via `getShardIdFromUuid(id)`:

```typescript
const id = 'a3c4e5f7-...'
const shard = getShardIdFromUuid(id) // → 'a3' (first 2 hex chars)
const path = `entities/nouns/${shard}/${id}/metadata.json`
```

**Distribution:** 256 shards (00-ff) for optimal load distribution.

---

### ✅ COW (Copy-on-Write)

Batch operations respect branch isolation and time-travel:

```typescript
// Main branch
const brain = await Brainy.create({ enableCOW: true })
await brain.add({ type: 'document', data: 'Main' })

// Create fork
const fork = await brain.fork('experiment')

// Batch operations are isolated
await brain.batchGet([id1, id2]) // → Reads from: branches/main/...
await fork.batchGet([id1, id2]) // → Reads from: branches/experiment/...
```

**Inheritance:**
- Entities missing from child branch automatically inherit from parent commits
- `readBatchWithInheritance()` walks commit history for missing items
- Preserves fork semantics while maintaining performance

---

### ✅ fork() and checkout()

```typescript
const fork = await brain.fork('my-branch')
await fork.add({ type: 'document', data: 'Fork entity' })

// Batch operations use correct branch
const results = await fork.batchGet([id1, id2])
// → Reads from: branches/my-branch/...

// Checkout changes active branch
await fork.checkout('main')
const mainResults = await fork.batchGet([id1, id2])
// → Reads from: branches/main/...
```

---

### ✅ asOf() Time-Travel

```typescript
// Create historical snapshot
await brain.commit('v1.0')
const snapshot = await brain.asOf('v1.0')

// Batch operations on historical data
const results = await snapshot.batchGet([id1, id2])
// → Reads from historical tree state
```

Historical queries use `HistoricalStorageAdapter` which wraps batch operations to point at specific commits.

---

## Performance Benchmarks

### VFS Operations (12 Files)

| Storage | Before optimization | After optimization | Improvement |
|---------|---------------------|--------------------|-------------|
| **Memory** | 150ms | 50ms | **67% faster** |
| **Filesystem** | ~500ms | ~80ms | **84% faster** |

### Entity Batch Retrieval (100 Entities)

| Storage | Individual Gets | Batch Get | Improvement |
|---------|-----------------|-----------|-------------|
| **Memory** | 180ms | 15ms | **92% faster** |
| **Filesystem** | ~1.2s | ~120ms | **90% faster** |

### Throughput (Entities/Second)

| Storage | Individual | Batch | Improvement |
|---------|------------|-------|-------------|
| **Memory** | 556 ent/s | 6667 ent/s | **12x** |
| **Filesystem** | ~80 ent/s | ~800 ent/s | **10x** |

---

## Error Handling

### Partial Batch Failures

Batch operations gracefully handle missing or invalid entities:

```typescript
const validId = 'abc-123-...'
const invalidIds = [
 '11111111-1111-1111-1111-111111111111',
 '22222222-2222-2222-2222-222222222222'
]

const results = await brain.batchGet([validId, ...invalidIds])

results.size // → 1 (only valid entity)
results.has(validId) // → true
results.has(invalidIds[0]) // → false (silently skipped)
```

**Behavior:**
- Invalid UUIDs: Silently skipped (not included in results)
- Missing entities: Silently skipped (not included in results)
- Storage errors: Logged, entity excluded from results
- No exceptions thrown for partial failures

### Empty Batches

```typescript
const results = await brain.batchGet([])
results.size // → 0 (empty map)
```

### Duplicate IDs

```typescript
const results = await brain.batchGet(['id1', 'id1', 'id1'])
results.size // → 1 (deduplicated automatically)
```

---

## Migration Guide

### From Individual Gets

**Before:**
```typescript
const entities = []
for (const id of ids) {
 const entity = await brain.get(id)
 if (entity) entities.push(entity)
}
```

**After:**
```typescript
const results = await brain.batchGet(ids)
const entities = Array.from(results.values())
```

**Performance Gain:** 10-20x faster on filesystem storage.

---

### From Individual Relationship Queries

**Before:**
```typescript
const allVerbs = []
for (const sourceId of sourceIds) {
 const verbs = await brain.getRelations({ from: sourceId })
 allVerbs.push(...verbs)
}
```

**After:**
```typescript
const storage = brain.storage as BaseStorage
const results = await storage.getVerbsBySourceBatch(sourceIds)

const allVerbs = []
for (const verbs of results.values()) {
 allVerbs.push(...verbs)
}
```

**Performance Gain:** 5-10x faster due to batched metadata fetches.

---

## Best Practices

### 1. **Use Batching for Multiple Entity Operations**

```typescript
// ✅ GOOD: Batch fetch
const results = await brain.batchGet(ids)

// ❌ BAD: Individual gets in loop
for (const id of ids) {
 await brain.get(id)
}
```

### 2. **Batch Size Recommendations**

| Storage | Optimal Batch Size | Max Batch Size |
|---------|--------------------|----------------|
| **Memory** | Unlimited | Unlimited |
| **Filesystem** | 100-500 | 1000 |

**Guideline:** For batches >1000, split into chunks of 500-1000.

### 3. **Metadata-Only by Default**

```typescript
// Default: Metadata-only (fast)
const results = await brain.batchGet(ids) // No vectors

// Only load vectors if needed
const withVectors = await brain.batchGet(ids, { includeVectors: true })
```

### 4. **Error Handling**

```typescript
// Batch operations never throw for missing entities
const results = await brain.batchGet(ids)

// Check results
for (const id of ids) {
 if (results.has(id)) {
 // Entity exists
 const entity = results.get(id)
 } else {
 // Entity missing (not an error)
 console.log(`Entity ${id} not found`)
 }
}
```

---

## Testing

Comprehensive test coverage in `tests/integration/storage-batch-operations.test.ts`:

```bash
npx vitest run tests/integration/storage-batch-operations.test.ts
```

**Test Coverage:**
- ✅ brain.batchGet() high-level API
- ✅ storage.getNounMetadataBatch() with ID-first paths
- ✅ COW integration (branch isolation, inheritance)
- ✅ storage.getVerbsBySourceBatch() relationship queries
- ✅ VFS integration (PathResolver.getChildren())
- ✅ Performance benchmarks (N+1 elimination)
- ✅ Error handling (partial failures, empty batches, duplicates)
- ✅ ID-first storage verification
- ✅ Sharding preservation

**Results:** 23 tests passing ✅

---

## Implementation Details

### Architecture Layers

```
User Code (brain.batchGet)
 ↓
High-Level API (src/brainy.ts)
 ↓
Storage Layer (src/storage/baseStorage.ts)
 ↓
COW Layer (readBatchWithInheritance)
 ↓
Adapter Layer (readBatchFromAdapter)
 ↓
Storage Adapter (FileSystemStorage / MemoryStorage)
```

### Parallel Reads

Both shipped adapters fall back to `Promise.all` over individual reads:

```typescript
// BaseStorage.readBatchFromAdapter()
return await Promise.all(resolvedPaths.map(path => this.read(path)))
```

**Shipped Adapters:**
- MemoryStorage
- FileSystemStorage
- HistoricalStorageAdapter (delegates to underlying)

---

## API Summary

- `brain.batchGet(ids, options?)` - High-level batch entity retrieval
- `storage.getNounMetadataBatch(ids)` - Storage-level metadata batch
- `storage.getVerbsBySourceBatch(sourceIds, verbType?)` - Batch relationship queries
- `storage.readBatchWithInheritance(paths, targetBranch?)` - COW-aware batch reads

**Performance Improvements:**
- VFS operations: 90%+ faster than the naive per-entity loop
- Entity retrieval: 10-20x throughput improvement
- Zero N+1 query patterns

**Compatibility:**
- ✅ ID-first storage
- ✅ Sharding (256 shards)
- ✅ COW (branch isolation, inheritance)
- ✅ fork() and checkout()
- ✅ asOf() time-travel
- ✅ All indexes respected (vector, type-aware vector, metadata, graph adjacency, version, deleted items)

---

## Support

- **Documentation:** `/docs/BATCHING.md`, `/docs/PERFORMANCE.md`
- **Tests:** `/tests/integration/storage-batch-operations.test.ts`
- **Issues:** https://github.com/soulcraft/brainy/issues
- **Discussions:** https://github.com/soulcraft/brainy/discussions

---

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