sqlitegraph 2.2.2

//! SQLite Neighbor Query Performance Test (Baseline Comparison)
//!
//! This test measures SQLite backend neighbor query performance
//! for comparison with V3 backend.

use sqlitegraph::{
    BackendDirection, EdgeSpec, GraphConfig, NeighborQuery, NodeSpec, SnapshotId, open_graph,
};
use std::time::Instant;
use tempfile::tempdir;

fn main() -> Result<(), Box<dyn std::error::Error>> {
    println!("═══════════════════════════════════════════════════════════════════");
    println!("  SQLite Neighbor Query Performance Test (Baseline)");
    println!("═══════════════════════════════════════════════════════════════════\n");

    let temp_dir = tempdir()?;
    let db_path = temp_dir.path().join("test.db");

    let graph = open_graph(&db_path, &GraphConfig::sqlite())?;
    println!("✅ Graph created with SQLite backend\n");

    // Insert 100 nodes
    let start = Instant::now();
    let mut node_ids = Vec::new();
    for i in 0..100 {
        let id = graph.insert_node(NodeSpec {
            kind: "Test".to_string(),
            name: format!("node_{}", i),
            file_path: None,
            data: serde_json::json!({"id": i}),
        })?;
        node_ids.push(id);
    }
    let insert_ms = start.elapsed().as_secs_f64() * 1000.0;
    println!("Inserted 100 nodes in {:.2}ms", insert_ms);

    // Insert edges from node 0 to nodes 1-20
    let start = Instant::now();
    for j in 1..=20 {
        graph.insert_edge(EdgeSpec {
            from: node_ids[0],
            to: node_ids[j as usize],
            edge_type: "test".to_string(),
            data: serde_json::Value::Null,
        })?;
    }
    let edge_ms = start.elapsed().as_secs_f64() * 1000.0;
    println!("Inserted 20 edges from node_0 in {:.2}ms\n", edge_ms);

    let snapshot = SnapshotId::current();
    let query = NeighborQuery {
        direction: BackendDirection::Outgoing,
        edge_type: None,
    };

    println!("───────────────────────────────────────────────────────────────────");
    println!("  COLD CACHE (First Query)");
    println!("───────────────────────────────────────────────────────────────────");

    // First query (cold cache)
    let start = Instant::now();
    let result = graph.neighbors(snapshot, node_ids[0], query.clone())?;
    let cold_ns = start.elapsed().as_nanos();
    println!("Cold query:  {} ns ({} neighbors)", cold_ns, result.len());
    println!("  → Includes: SQLite query planning + index lookup + row fetch\n");

    println!("───────────────────────────────────────────────────────────────────");
    println!("  WARM CACHE (After 100 Warmup Queries)");
    println!("───────────────────────────────────────────────────────────────────");

    // Warm up queries
    for _ in 0..100 {
        let _ = graph.neighbors(snapshot, node_ids[0], query.clone())?;
    }

    // Benchmark 10,000 queries
    let start = Instant::now();
    for _ in 0..10000 {
        let _ = graph.neighbors(snapshot, node_ids[0], query.clone())?;
    }
    let total_time = start.elapsed();
    let hot_ns = total_time.as_nanos() / 10000;

    println!("Hot queries: {} queries in {:?}", 10000, total_time);
    println!("  Average:   {} ns/query", hot_ns);
    println!("  → Includes: Prepared statement + SQLite cache hit\n");

    println!("═══════════════════════════════════════════════════════════════════");
    println!("  RESULTS SUMMARY");
    println!("═══════════════════════════════════════════════════════════════════");
    println!("  Cold path (first query):       {} ns", cold_ns);
    println!("  Hot path  (cached):            {} ns", hot_ns);
    println!(
        "  Cache warmup benefit:          {}× faster",
        cold_ns as f64 / hot_ns as f64
    );
    println!("");

    if hot_ns < 500 {
        println!("  ✅ EXCELLENT: Hot path < 500 ns (SQLite's B-tree is highly optimized)");
    } else if hot_ns < 1000 {
        println!("  ✅ VERY GOOD: Hot path < 1 μs");
    } else {
        println!("  ⚠️  OK: Hot path {} μs", hot_ns / 1000);
    }

    println!("\n  NOTE: SQLite's advantage is in mature B-tree + prepared statement cache");
    println!("        Point lookups are SQLite's strength due to decades of optimization");
    println!("═══════════════════════════════════════════════════════════════════");

    Ok(())
}