Sqlx - Sqlite Pool

Cargo.toml

[package]
name = "sqlx-pool-sqlite"
version = "0.1.0"
edition = "2018"

[dependencies]
sqlx = { version = "0.4", default-features = false, features = [ "runtime-tokio-native-tls", "macros", "sqlite" ] }
tokio = { version = "0.2", features = ["full"] }

main.rs

#[tokio::main]
async fn main() {
    let db = sqlx::pool::PoolOptions::<sqlx::Sqlite>::new()
        .max_connections(16)
        .connect_with(sqlx::sqlite::SqliteConnectOptions::new().filename("/tmp/test-sqlx.db"))
        .await
        .unwrap();

    {
        let mut handles = vec![];
        for _ in 0usize..16 {
            let mut h = db.acquire().await.unwrap();
            sqlx::query("PRAGMA synchronous=NORMAL")
                .execute(&mut h)
                .await
                .unwrap();
            handles.push(h);
        }
    }

    sqlx::query!(
        "CREATE TABLE IF NOT EXISTS users (
            name TEXT PRIMARY KEY NOT NULL
        );
        DELETE FROM users;
        ",
    )
    .execute(&db)
    .await
    .unwrap();

    let mut guards = vec![];

    for i in 0..16 {
        let db = db.clone();
        let guard = tokio::spawn(async move {
            for j in 0..10000i32 {
                drop(
                    sqlx::query!("SELECT * FROM users")
                        .fetch_optional(&db)
                        .await
                        .unwrap(),
                );
                let name = format!("John{}a{}", i, j * 2);
                let name = &name;
                sqlx::query!("INSERT INTO users VALUES(?)", name)
                    .execute(&db)
                    .await
                    .unwrap();
            }
        });

        guards.push(guard);
    }
    for guard in guards {
        guard.await.unwrap();
    }
}