-- Create table
CREATE TABLE IF NOT EXISTS products (
    id SERIAL PRIMARY KEY,
    name VARCHAR(255) NOT NULL,
    price NUMERIC(10,2) NOT NULL
);

-- Insert 100,000 products
INSERT INTO products (name, price)
SELECT
    'Product ' || i,
    ROUND((RANDOM() * 1000)::numeric, 2)
FROM generate_series(1, 1000000) AS s(i);

@Entity
@Table(name = "products")
public class Product {
    @Id
    private Long id;
    private String name;
    private Double price;

    public Product() {
    }

    public Product(Long id, String name, Double price) {
        this.id = id;
        this.name = name;
        this.price = price;
    }

    public Long getId() {
        return id;
    }

    public String getName() {
        return name;
    }

    public Double getPrice() {
        return price;
    }

    @Override
    public String toString() {
        return "Product[" +
                "id=" + id + ", " +
                "name=" + name + ", " +
                "price=" + price + ']';
    }
}

import org.springframework.data.jpa.repository.JpaRepository;

public interface ProductRepository extends JpaRepository<Product, Long> {
}

@RestController
@RequestMapping("/products")
public class ProductController {

    private final ProductRepository productRepository;

    public ProductController(ProductRepository productRepository) {
        this.productRepository = productRepository;
    }

    @GetMapping
    public List<Product> getAll(){
       return productRepository.findAll();
    }
}

@GetMapping("/stream")
    public StreamingResponseBody getAllStreamed(HttpServletResponse response){
       response.setContentType("text/event-stream");
       return outputStream -> {
           productRepository.findAll()
                    .forEach(product -> {
                        try {
                            String json = new ObjectMapper().writeValueAsString(product) + "\n";
                            outputStream.write(json.getBytes());
                            outputStream.flush();
                        } catch (JsonProcessingException e) {
                            log.error("Error parsing product to json", e);
                        } catch (IOException e) {
                            log.error("Error writing object to stream", e);
                        }
                    });
    };
}