How will other coroutines behave if one of them performs reading a large file using open().read() in asyncio?

The open().read() method in Python is a blocking I/O operation that is not asynchronous. If an asyncio coroutine performs open().read() to read a large file, it blocks the thread in which the event loop is running.

As a result, other coroutines running in the same event loop cannot execute until the file reading is complete. This leads to a 'freeze' of the asynchronous application.

To avoid this, special asynchronous libraries (such as aiofiles) are used for reading files in asyncio, which perform I/O operations in a separate thread or use non-blocking calls, allowing other coroutines to continue working:

import aiofiles
import asyncio

async def read_file(path):
    async with aiofiles.open(path, 'r') as f:
        contents = await f.read()
    return contents

Thus, using blocking I/O operations in asyncio breaks asynchronous behavior and reduces performance.