But when checking benchmarks and comparisons you should keep the following in mind.

## Benchmarks and speed

When you check the benchmarks, it is common to see several tools of different types compared as equivalent.

Specifically, to see Uvicorn, Starlette and FastAPI compared together (among many other tools).

Alternatively, if you don't have a way to provide a command line option like `--root-path` or equivalent, you can set the `root_path` parameter when creating your FastAPI app:

```Python hl_lines="3"
{!../../../docs_src/behind_a_proxy/tutorial002.py!}
```

Passing the `root_path` to `FastAPI` would be the equivalent of passing the `--root-path` command line option to Uvicorn or Hypercorn.

### About `root_path`

!!! note
    The command `uvicorn main:app` refers to:

    * `main`: the file `main.py` (the Python "module").
    * `app`: the object created inside of `main.py` with the line `app = FastAPI()`.

    It is equivalent to:

    ```Python
    from main import app
    ```

!!! warning
    Uvicorn and others support a `--reload` option that is useful during development.

    This section doesn't apply those ideas, to be equivalent to the counterpart in <a href="https://www.starlette.io/database/" class="external-link" target="_blank">Starlette</a>.

## Import and set up `SQLAlchemy`

* Import `SQLAlchemy`.
* Create a `metadata` object.

    ```Python hl_lines="31  37"
    {!> ../../../docs_src/response_model/tutorial005.py!}
    ```

!!! tip
    The syntax `{"name", "description"}` creates a `set` with those two values.

    It is equivalent to `set(["name", "description"])`.

#### Using `list`s instead of `set`s

If you forget to use a `set` and use a `list` or `tuple` instead, FastAPI will still convert it to a `set` and it will work correctly:

`Optional[Something]` is actually a shortcut for `Union[Something, None]`, they are equivalent.

This also means that in Python 3.10, you can use `Something | None`:

=== "Python 3.10+"

    ```Python hl_lines="1"
    {!> ../../../docs_src/python_types/tutorial009_py310.py!}
    ```

So, continuing with the `user_dict` from above, writing:

```Python
UserInDB(**user_dict)
```

would result in something equivalent to:

```Python
UserInDB(
    username="john",
    password="secret",
    email="******@****.***",
    full_name=None,
)
```

And multiple processes normally **don't share any memory**. This means that each running process has its own things, variables, and memory. And if you are consuming a large amount of memory in your code, **each process** will consume an equivalent amount of memory.

### Server Memory

**FastAPI** provides a convenience tool to structure your application while keeping all the flexibility.

!!! info
    If you come from Flask, this would be the equivalent of Flask's Blueprints.

## An example file structure

Let's say you have a file structure like this:

```
.
├── app
│   ├── __init__.py
│   ├── main.py
│   ├── dependencies.py
│   └── routers

    * You can imagine that `main:app` is equivalent to a Python `import` statement like:

        ```Python
        from main import app
        ```

    * So, the colon in `main:app` would be equivalent to the Python `import` part in `from main import app`.