async fn new(url: Self::Config) -> Self {

        let pool = PgPool::connect(&url).await.unwrap();

        let mut conn = pool.acquire().await.unwrap();

        conn.execute(r#"DROP SCHEMA IF EXISTS commerce_bench CASCADE"#)

            .await

            .unwrap();

        conn.execute(r#"CREATE SCHEMA commerce_bench"#)

            .await

            .unwrap();

        conn.execute("SET search_path='commerce_bench';")

            .await

            .unwrap();

        conn.execute(

            r#"CREATE TABLE customers (

            id SERIAL PRIMARY KEY,

            name TEXT,

            email TEXT,

            address TEXT,

            city TEXT,

            region TEXT,

            country TEXT,

            postal_code TEXT,

            phone TEXT

        )"#,

        )

        .await

        .unwrap();

        conn.execute(

            r#"CREATE TABLE products (

                    id SERIAL PRIMARY KEY,

                    name TEXT

                )"#,

        )

        .await

        .unwrap();

        conn.execute(r#"CREATE INDEX products_by_name ON products(name)"#)

            .await

            .unwrap();

        conn.execute(

            r#"CREATE TABLE product_reviews (

                product_id INTEGER NOT NULL,-- REFERENCES products(id),

                customer_id INTEGER NOT NULL,-- REFERENCES customers(id),

                rating INTEGER NOT NULL,

                review TEXT

            )"#,

        )

        .await

        .unwrap();

        conn.execute(r#"CREATE INDEX product_reviews_by_product ON product_reviews(product_id)"#)

            .await

            .unwrap();

        conn.execute(r#"CREATE UNIQUE INDEX product_reviews_by_customer ON product_reviews(customer_id, product_id)"#)

            .await

            .unwrap();

        conn.execute(

            r#"CREATE MATERIALIZED VIEW

                    product_ratings

                AS

                    SELECT

                        product_id,

                        sum(rating)::int as total_rating,

                        count(rating)::int as ratings

                    FROM

                        product_reviews

                    GROUP BY product_id

            "#,

        )

        .await

        .unwrap();

        conn.execute(

            r#"CREATE TABLE categories (

                    id SERIAL PRIMARY KEY,

                    name TEXT

                )"#,

        )

        .await

        .unwrap();

        conn.execute(

            r#"CREATE TABLE product_categories (

                    product_id INTEGER,-- REFERENCES products(id),

                    category_id INTEGER-- REFERENCES categories(id)

                )"#,

        )

        .await

        .unwrap();

        conn.execute(

            r#"CREATE INDEX product_categories_by_product ON product_categories(product_id)"#,

        )

        .await

        .unwrap();

        conn.execute(

            r#"CREATE INDEX product_categories_by_category ON product_categories(category_id)"#,

        )

        .await

        .unwrap();

        conn.execute(

            r#"CREATE TABLE orders (

                    id SERIAL PRIMARY KEY,

                    customer_id INTEGER -- REFERENCES customers(id)

                )"#,

        )

        .await

        .unwrap();

        conn.execute(

            r#"CREATE TABLE order_products (

                    order_id INTEGER NOT NULL,-- REFERENCES orders(id),

                    product_id INTEGER NOT NULL -- REFERENCES products(id)

                )"#,

        )

        .await

        .unwrap();

        conn.execute(

            r#"CREATE TABLE carts (

            id SERIAL PRIMARY KEY,

            customer_id INTEGER

        )"#,

        )

        .await

        .unwrap();

        conn.execute(

            r#"CREATE TABLE cart_products (

                cart_id INTEGER,

                product_id INTEGER

            )"#,

        )

        .await

        .unwrap();

        Self { pool }

    }

    async fn new_operator_async(&self) -> Self::Operator {

        PostgresOperator {

            sqlite: self.pool.clone(),

        }

    }

    async fn operate(

        &mut self,

        operation: &Load,

        _results: &[OperationResult<u32>],

        measurements: &Measurements,

    ) -> OperationResult<u32> {

        let measurement = measurements.begin("postgresql", Metric::Load);

        let mut conn = self.sqlite.acquire().await.unwrap();

        let mut tx = conn.begin().await.unwrap();

        let insert_category = tx

            .prepare("INSERT INTO commerce_bench.categories (id, name) VALUES ($1, $2)")

            .await

            .unwrap();

        for (id, category) in &operation.initial_data.categories {

            let mut args = PgArguments::default();

            args.reserve(2, 0);

            args.add(*id as i32);

            args.add(&category.name);

            tx.execute(insert_category.query_with(args)).await.unwrap();

        let insert_product = tx

            .prepare("INSERT INTO commerce_bench.products (id, name) VALUES ($1, $2)")

            .await

            .unwrap();

        let insert_product_category = tx

            .prepare("INSERT INTO commerce_bench.product_categories (product_id, category_id) VALUES ($1, $2)")

            .await

            .unwrap();

        for (&id, product) in &operation.initial_data.products {

            let mut args = PgArguments::default();

            args.reserve(2, 0);

            args.add(id as i32);

            args.add(&product.name);

            tx.execute(insert_product.query_with(args)).await.unwrap();

            for &category_id in &product.category_ids {

                let mut args = PgArguments::default();

                args.reserve(2, 0);

                args.add(id as i32);

                args.add(category_id as i32);

                tx.execute(insert_product_category.query_with(args))

                    .await

                    .unwrap();

        let insert_customer = tx

            .prepare("INSERT INTO commerce_bench.customers (id, name, email, address, city, region, country, postal_code, phone) VALUES ($1, $2, $3, $4, $5, $6, $7, $8, $9)")

            .await

            .unwrap();

        for (id, customer) in &operation.initial_data.customers {

            let mut args = PgArguments::default();

            args.reserve(9, 0);

            args.add(*id as i32);

            args.add(&customer.name);

            args.add(&customer.email);

            args.add(&customer.address);

            args.add(&customer.city);

            args.add(&customer.region);

            args.add(&customer.country);

            args.add(&customer.postal_code);

            args.add(&customer.phone);

            tx.execute(insert_customer.query_with(args)).await.unwrap();

        let insert_order = tx

            .prepare("INSERT INTO commerce_bench.orders (id, customer_id) VALUES ($1, $2)")

            .await

            .unwrap();

        let insert_order_product = tx

            .prepare(

                "INSERT INTO commerce_bench.order_products (order_id, product_id) VALUES ($1, $2)",

            )

            .await

            .unwrap();

        for (&id, order) in &operation.initial_data.orders {

            let mut args = PgArguments::default();

            args.reserve(2, 0);

            args.add(id as i32);

            args.add(order.customer_id as i32);

            tx.execute(insert_order.query_with(args)).await.unwrap();

            for &product_id in &order.product_ids {

                let mut args = PgArguments::default();

                args.reserve(2, 0);

                args.add(id as i32);

                args.add(product_id as i32);

                tx.execute(insert_order_product.query_with(args))

                    .await

                    .unwrap();

        let insert_review = tx

            .prepare("INSERT INTO commerce_bench.product_reviews (product_id, customer_id, rating, review) VALUES ($1, $2, $3, $4)")

            .await

            .unwrap();

        for review in &operation.initial_data.reviews {

            let mut args = PgArguments::default();

            args.reserve(4, 0);

            args.add(review.product_id as i32);

            args.add(review.customer_id as i32);

            args.add(review.rating as i32);

            args.add(&review.review);

            tx.execute(insert_review.query_with(args)).await.unwrap();

        tx.execute(

            "SELECT setval('commerce_bench.orders_id_seq', COALESCE((SELECT MAX(id)+1 FROM commerce_bench.orders), 1), false)",

        )

        .await

        .unwrap();

        tx.commit().await.unwrap();

        // Make sure all ratings show up in the view.

        conn.execute("REFRESH MATERIALIZED VIEW commerce_bench.product_ratings")

            .await

            .unwrap();

        // This makes a significant difference.

        conn.execute("ANALYZE").await.unwrap();

        measurement.finish();

        OperationResult::Ok

    }

    async fn operate(

        &mut self,

        _operation: &CreateCart,

        _results: &[OperationResult<u32>],

        measurements: &Measurements,

    ) -> OperationResult<u32> {

        let measurement = measurements.begin("postgresql", Metric::CreateCart);

        let mut conn = self.sqlite.acquire().await.unwrap();

        let mut tx = conn.begin().await.unwrap();

        let statement = tx

            .prepare("insert into commerce_bench.carts (customer_id) values (null) returning id")

            .await

            .unwrap();

        let result = tx.fetch_one(statement.query()).await.unwrap();

        tx.commit().await.unwrap();

        let id: i32 = result.get(0);

        measurement.finish();

        OperationResult::Cart { id: id as u32 }

    }

    async fn operate(

        &mut self,

        operation: &AddProductToCart,

        results: &[OperationResult<u32>],

        measurements: &Measurements,

    ) -> OperationResult<u32> {

        let cart = match &results[operation.cart.0] {

            OperationResult::Cart { id } => *id,

        let product = match &results[operation.product.0] {

            OperationResult::Product { id, .. } => *id,

        let measurement = measurements.begin("postgresql", Metric::AddProductToCart);

        let mut conn = self.sqlite.acquire().await.unwrap();

        let mut tx = conn.begin().await.unwrap();

        let statement = tx

            .prepare(

                "insert into commerce_bench.cart_products (cart_id, product_id) values ($1, $2)",

            )

            .await

            .unwrap();

        let mut args = PgArguments::default();

        args.reserve(2, 0);

        args.add(cart as i32);

        args.add(product as i32);

        tx.execute(statement.query_with(args)).await.unwrap();

        tx.commit().await.unwrap();

        measurement.finish();

        OperationResult::CartProduct { id: product }

    }

    async fn operate(

        &mut self,

        operation: &FindProduct,

        _results: &[OperationResult<u32>],

        measurements: &Measurements,

    ) -> OperationResult<u32> {

        let measurement = measurements.begin("postgresql", Metric::FindProduct);

        let mut conn = self.sqlite.acquire().await.unwrap();

        let statement = conn

            .prepare(

                r#"

                SELECT

                    id,

                    name,

                    category_id,

                    commerce_bench.product_ratings.total_rating as "total_rating: Option<i32>",

                    commerce_bench.product_ratings.ratings as "ratings: Option<i32>"

                FROM

                    commerce_bench.products

                LEFT OUTER JOIN commerce_bench.product_categories ON

                    commerce_bench.product_categories.product_id = id

                LEFT OUTER JOIN commerce_bench.product_ratings ON

                    commerce_bench.product_ratings.product_id = id

                WHERE name = $1

                GROUP BY id, name, category_id, commerce_bench.product_ratings.total_rating, commerce_bench.product_ratings.ratings

            "#,

            )

            .await

            .unwrap();

        let mut args = PgArguments::default();

        args.reserve(1, 0);

        args.add(&operation.name);

        let mut results = conn.fetch(statement.query_with(args));

        let mut id: Option<i32> = None;

        let mut name = None;

        let mut category_ids = Vec::new();

        let mut total_rating: Option<i32> = None;

        let mut rating_count: Option<i32> = None;

        while let Some(row) = results.next().await {

            let row = row.unwrap();

            id = Some(row.get(0));

            name = Some(row.get(1));

            total_rating = row.get(2);

            rating_count = row.get(3);

            if let Some(category_id) = row.get::<Option<i32>, _>(2) {

                category_ids.push(category_id as u32);

            }

        let rating_count = rating_count.unwrap_or_default();

        let total_rating = total_rating.unwrap_or_default();

        measurement.finish();

        OperationResult::Product {

            id: id.unwrap() as u32,

            product: Product {

                name: name.unwrap(),

                category_ids,

            },

            rating: if rating_count > 0 {

                Some(total_rating as f32 / rating_count as f32)

                None

    }

    async fn operate(

        &mut self,

        operation: &LookupProduct,

        _results: &[OperationResult<u32>],

        measurements: &Measurements,

    ) -> OperationResult<u32> {

        let measurement = measurements.begin("postgresql", Metric::LookupProduct);

        let mut conn = self.sqlite.acquire().await.unwrap();

        let statement = conn

            .prepare(

                r#"

                    SELECT

                        id,

                        name,

                        category_id,

                        commerce_bench.product_ratings.total_rating as "total_rating: Option<i32>",

                        commerce_bench.product_ratings.ratings as "ratings: Option<i32>"

                    FROM

                        commerce_bench.products

                    LEFT OUTER JOIN commerce_bench.product_categories ON

                        commerce_bench.product_categories.product_id = id

                    LEFT OUTER JOIN commerce_bench.product_ratings ON

                        commerce_bench.product_ratings.product_id = id

                    WHERE id = $1

                    GROUP BY id, name, category_id, commerce_bench.product_ratings.total_rating, commerce_bench.product_ratings.ratings

                "#,

            )

            .await

            .unwrap();

        let mut args = PgArguments::default();

        args.reserve(1, 0);

        args.add(operation.id as i32);

        let mut results = conn.fetch(statement.query_with(args));

        let mut id: Option<i32> = None;

        let mut name = None;

        let mut category_ids = Vec::new();

        let mut total_rating: Option<i32> = None;

        let mut rating_count: Option<i32> = None;

        while let Some(row) = results.next().await {

            let row = row.unwrap();

            id = Some(row.get(0));

            name = Some(row.get(1));

            total_rating = row.get(2);

            rating_count = row.get(3);

            if let Some(category_id) = row.get::<Option<i32>, _>(2) {

                category_ids.push(category_id as u32);

            }

        let rating_count = rating_count.unwrap_or_default();

        let total_rating = total_rating.unwrap_or_default();

        measurement.finish();

        OperationResult::Product {

            id: id.unwrap() as u32,

            product: Product {

                name: name.unwrap(),

                category_ids,

            },

            rating: if rating_count > 0 {

                Some(total_rating as f32 / rating_count as f32)

                None

    }

    async fn operate(

        &mut self,

        operation: &Checkout,

        results: &[OperationResult<u32>],

        measurements: &Measurements,

    ) -> OperationResult<u32> {

        let cart = match &results[operation.cart.0] {

            OperationResult::Cart { id } => *id as i32,

        let measurement = measurements.begin("postgresql", Metric::Checkout);

        let mut conn = self.sqlite.acquire().await.unwrap();

        let mut tx = conn.begin().await.unwrap();

        let statement = tx

            .prepare(r#"INSERT INTO commerce_bench.orders (customer_id) VALUES ($1) RETURNING ID"#)

            .await

            .unwrap();

        let mut args = PgArguments::default();

        args.reserve(1, 0);

        args.add(operation.customer_id as i32);

        let result = tx.fetch_one(statement.query_with(args)).await.unwrap();

        let order_id: i32 = result.get(0);

        let statement = tx

            .prepare(r#"

                WITH products_in_cart AS (

                    DELETE FROM commerce_bench.cart_products WHERE cart_id = $1 RETURNING $2::int as order_id, product_id

                )

                INSERT INTO commerce_bench.order_products (order_id, product_id) SELECT * from products_in_cart;"#)

            .await

            .unwrap();

        let mut args = PgArguments::default();

        args.reserve(2, 0);

        args.add(cart);

        args.add(order_id);

        tx.execute(statement.query_with(args)).await.unwrap();

        let statement = tx

            .prepare(r#"DELETE FROM commerce_bench.carts WHERE id = $1"#)

            .await

            .unwrap();

        let mut args = PgArguments::default();

        args.reserve(1, 0);

        args.add(cart);

        tx.execute(statement.query_with(args)).await.unwrap();

        tx.commit().await.unwrap();

        measurement.finish();

        OperationResult::Ok

    }

    async fn operate(

        &mut self,

        operation: &ReviewProduct,

        results: &[OperationResult<u32>],

        measurements: &Measurements,

    ) -> OperationResult<u32> {

        let product = match &results[operation.product_id.0] {

            OperationResult::CartProduct { id, .. } => *id,

        let measurement = measurements.begin("postgresql", Metric::RateProduct);

        let mut conn = self.sqlite.acquire().await.unwrap();

        let mut tx = conn.begin().await.unwrap();

        let statement = tx

            .prepare(

                r#"INSERT INTO commerce_bench.product_reviews (

                        product_id,

                        customer_id,

                        rating,

                        review)

                    VALUES ($1, $2, $3, $4)

                    ON CONFLICT (customer_id, product_id) DO UPDATE SET rating = $3, review = $4"#,

            )

            .await

            .unwrap();

        let mut args = PgArguments::default();

        args.reserve(4, 0);

        args.add(product as i32);

        args.add(operation.customer_id as i32);

        args.add(operation.rating as i32);

        args.add(&operation.review);

        tx.execute(statement.query_with(args)).await.unwrap();

        tx.commit().await.unwrap();

        // Make this rating show up

        conn.execute("REFRESH MATERIALIZED VIEW commerce_bench.product_ratings")

            .await

            .unwrap();

        measurement.finish();

        OperationResult::Ok

    }