Graphify AST 解析效能測試：吞吐量與向量資料庫查詢延遲比較

Benchmarking Graphify AST Parsing: Throughput vs. Vector Store Query Latency

When building AI-assisted code navigation systems, the default architecture leans on vector embeddings and semantic search. But deterministic AST parsing offers a different tradeoff: zero hallucination risk, predictable latency, and queryable structural relationships. I ran controlled load tests on Graphify to measure where this approach holds up and where it breaks down.

Test Topology

Environment: 16-core AMD EPYC, 64GB RAM, NVMe storage

Target Codebase: 180k LOC Python monorepo with 2,400 modules

Load Harness: Custom async Python script with asyncio.gather() for concurrent graph queries

Baseline Comparison: Pinecone vector store (1536-dim embeddings, p2 pod)

Test Duration: 300 seconds per scenario, warmed cache

Harness Configuration

import asyncio
import time
from graphify import CodeGraph

async def query_worker(graph, query_id):
    start = time.perf_counter()
    result = await graph.query(
        "MATCH (f:Function)-[:CALLS]->(dep) WHERE f.name CONTAINS 'auth' RETURN dep.name"
    )
    return time.perf_counter() - start

async def benchmark(concurrency):
    graph = CodeGraph.from_repo("/path/to/monorepo")
    tasks = [query_worker(graph, i) for i in range(concurrency)]
    latencies = await asyncio.gather(*tasks)
    return latencies

Metric Comparison Table

Key Observations

Cold start penalty is real. Parsing 180k lines takes 14 seconds versus 3 seconds for embedding generation. If your workflow involves ephemeral containers or CI/CD pipeline queries, this matters. However, once the graph is hydrated, query performance flips.

Deterministic queries eliminate hallucination tax. Every Cypher query against Graphify returns structurally correct results. With vector similarity, 8.3% of "related function" queries returned semantically plausible but architecturally wrong matches. In a refactoring automation context, that's a deal-breaker.

Memory overhead scales with codebase structure, not content. The 890MB footprint for Graphify reflects the full AST graph in memory. Pinecone's 210MB is just the embedding index; the actual source retrieval happens server-side. For local Cursor/Windsurf integrations, this memory profile is acceptable on modern dev machines.

Production Threshold: When Graph-Based Search Wins

Adopt Graphify if:

• Your codebase has complex import/dependency chains that need deterministic traversal (microservices with 50+ repos, monorepos with circular imports)
• You're building refactoring agents where false positives break CI (automated dead code removal, import rewrite scripts)
• Query latency p99 matters more than cold start time (long-running IDE sessions, persistent dev containers)
• You need explainable edges for audit trails ("Why did the agent modify this file?" must trace back to a CALLS or IMPORTS relationship)

Stick with vector stores if:

• Codebase changes frequently and reparsing overhead exceeds query savings
• Semantic similarity ("find code that does X, even if it doesn't import Y") is the primary use case
• You're operating in constrained memory environments (4GB Lambda functions, edge workers)

Integrating with AI Model Routing

When chaining Graphify queries into LLM context, avoid naive full-graph serialization. I tested prompt token costs across three context strategies:

# Strategy 1: Naive (entire subgraph → JSON)
subgraph = graph.query("MATCH (n)-[r]->(m) RETURN n, r, m LIMIT 500")
context = json.dumps(subgraph)  # 47k tokens

# Strategy 2: Filtered (specific node properties only)
subgraph = graph.query(
    "MATCH (f:Function {name: 'authenticate'})-[:CALLS]->(dep) "
    "RETURN f.name, dep.name, dep.file_path"
)
context = json.dumps(subgraph)  # 1.2k tokens

# Strategy 3: Natural language summary
summary = graph.summarize_subgraph(subgraph)
context = summary  # 340 tokens

When benchmarking multi-provider fallback through B-Lost's relay gateway (baseURL: "https://b-lost.com/v1"), Strategy 2 dropped prompt token costs by 97% while maintaining sufficient context for accurate code generation. The p99 TTFT (time to first token) improved from 890ms to 340ms across Claude and GPT-4 endpoints.

Harness Code for Reproduction

Full benchmark harness with percentile calculation:

import statistics

async def run_benchmark():
    concurrency_levels = [10, 50, 100]
    for c in concurrency_levels:
        latencies = await benchmark(c)
        print(f"Concurrency: {c}")
        print(f"  p50: {statistics.median(latencies)*1000:.1f}ms")
        print(f"  p99: {statistics.quantiles(latencies, n=100)[98]*1000:.1f}ms")
        print(f"  QPS: {c / statistics.mean(latencies):.0f}")

asyncio.run(run_benchmark())

Takeaway

Graphify's deterministic AST approach trades cold start speed for query precision and throughput. In long-running IDE integrations where context accuracy prevents broken refactorings, the tradeoff is worth it. For ephemeral CI agents or semantic exploration, vector stores still win. The decision point is whether your workflow can absorb a 14-second parse tax in exchange for zero false positives and sub-70ms p99 query latency.