zero-postgres 0.9.0

//! Benchmark: tokio-postgres
//!
//! Usage:
//!   DATABASE_URL=postgres://user:pass@localhost/test cargo run --example bench_tokio_postgres

use std::env;
use tokio_postgres::NoTls;

fn main() -> Result<(), Box<dyn std::error::Error>> {
    tokio::runtime::Builder::new_current_thread()
        .enable_all()
        .build()?
        .block_on(async_main())
}

async fn async_main() -> Result<(), Box<dyn std::error::Error>> {
    let url = env::var("DATABASE_URL")?;
    // tokio-postgres expects postgres:// not pg://
    let url = url
        .strip_prefix("pg://")
        .map(|s| format!("postgres://{}", s))
        .unwrap_or(url);
    let (client, connection) = tokio_postgres::connect(&url, NoTls).await?;

    tokio::spawn(async move {
        if let Err(e) = connection.await {
            eprintln!("connection error: {}", e);
        }
    });

    // Setup - use temp table (session-scoped, often memory-resident)
    client
        .execute(
            "CREATE TEMP TABLE test_bench (
                id SERIAL PRIMARY KEY,
                name VARCHAR(100),
                age INT,
                email VARCHAR(100),
                score REAL,
                description VARCHAR(100)
            )",
            &[],
        )
        .await?;

    let stmt = client
        .prepare(
            "INSERT INTO test_bench (name, age, email, score, description) VALUES ($1, $2, $3, $4, $5)",
        )
        .await?;

    const N: usize = 10000;
    let mut rows = Vec::with_capacity(N);
    for i in 0..N {
        rows.push((
            format!("user_{}", i),
            (20 + (i % 50)) as i32,
            format!("user{}@example.com", i),
            (i % 100) as f32 / 10.0,
            format!("Description for user {}", i),
        ));
    }

    for iteration in 0..10 {
        let iteration_start = std::time::Instant::now();

        for (username, age, email, score, description) in rows.iter() {
            client
                .execute(&stmt, &[username, age, email, score, description])
                .await?;
        }

        let elapsed = iteration_start.elapsed();
        let row = client
            .query_one("SELECT COUNT(*) FROM test_bench", &[])
            .await?;
        let count: i64 = row.get(0);
        println!(
            "Iteration {}: Inserted {} rows (took {:.2}ms)",
            iteration,
            count,
            elapsed.as_secs_f64() * 1000.0
        );
        client.execute("TRUNCATE TABLE test_bench", &[]).await?;
    }

    Ok(())
}