Great content brother Quick Modification: sync router is Concurrency not Parallelism. In python parallelism is achieved only by multiprocessing

Great video, but I think it’s important to mention that multi-threading in Python is not parallel

@bakasenpaidesu

Ай бұрын

Multi processing*

@vladhaidukkk-learning

Ай бұрын

​@@bakasenpaidesu Actually you are wrong; multiprocessing is parallel because Python spawns an entirely new process with an entirely new interpreter.

@benshapiro9731

4 күн бұрын

Multi threading in python is technically also parallel programming whenever a thread releases the GIL, such as during time.sleep or open calls. In those specific instances, there can be two (or more) threads truly executing in parallel in the same python process, because one thread is waiting for the results of a system call, during which time it releases the GIL since reference counts don’t need to be updated, allowing another thread to acquire the GIL and execute a piece of code in parallel.

@benshapiro9731

4 күн бұрын

On this topic also: check out the beta of. Python 3.13! There is a flag that can be passed when launching python that removes the GIL, allowing truly parallelized execution with just threads. Been playing around with asyncio and concurrent.futures.ThreadPoolExecutor -> noticeable speed up. Shame that c-extension based libraries like numpy are unusable with this setting

@vladhaidukkk-learning

4 күн бұрын

​@@benshapiro9731 This is called concurrency, not parallelism. Parallelism is when two or more tasks can run simultaneously, using the CPU, without waiting for I/O-bound operations. While the GIL doesn't prevent Python from switching context between threads waiting for I/O-bound operations, this is still considered concurrency, not parallelism.

Clearly explained!! Thank you

Thanks for clearing this concept.

OMG! This is so helpful and a great video. Thank you and please post more videos like this!

Thank you for this, I always wondered the difference between async def and def

Nice explanation. Concise and to the point.

Beautifully explained!

Great explanation, you should create more videos bro...

Great video. Thanks

very well explanation.

My question would be how FastAPI then manages workload when it´s handed over to the worker thread. Because I can only see one worker thread running, at the same time it handles 40 'workloads' concurrently.

great video

Thanks man for the video. I am trying to use fast api for db CRUD, which one do you think i should use for get post put and delete?

@codecollider

2 ай бұрын

It depends on whether your database library supports non-blocking queries. Ideally, for endpoints involving database calls, use async def if your library allows awaiting query execution (like await db.execute()). If you're using SQLAlchemy, it provides both blocking and non-blocking methods for queries. It's generally recommended to use the non-blocking approach for better performance.

@thanhlongle6276

2 ай бұрын

@@codecollider thank you, everything i write is in normal, non async, and I am using sqlite3 package. I think i will use normal def for all of it, since they are all parallel, and the blocking of read and write on database is performed by SQLite itself

I need some help, I want to create a fast api endpoint that calls a synchronous function that has a lot of blocking I/0 operations. But I want the endpoint function to run asynchronously so it can accept many requests at the same time. How should I do this, is there an alternative approach?

@Praise-rs4mc

27 күн бұрын

The only way to achieve that is to use multi-threading which I advice against.... instead, make the function asynchronous and try to find the non-blocking function for what you want to do...

@Praise-rs4mc

27 күн бұрын

Better still, use the run_in_threadpool function from fastapi to run the process in a different thread so that you don't block the event...better than implementing multi threading on your own.

@lwangacaleb2729

27 күн бұрын

@@Praise-rs4mc thanks alot, I will give it a try.

def endpoint3() is not running parallely for me as supposed to what u said in the video. Instead it is sunning one at a time. Do u know why?

@codecollider

23 күн бұрын

I believe you are testing APIs in the browser. Sometimes, browsers like Chrome have limitations on making parallel requests to the same URL. In the video, if you look closely, I am using two different browsers to hit the same API in parallel. You can try the same approach.

@arjunc5896

22 күн бұрын

@@codecollider Yes you are right. I tried from different browsers and it worked. Strange though. Thanks

❤

2nd and 3rd are both concurrent I think..parallelism is achieved only by multiprocessing

@codecollider

Ай бұрын

For true parallelism, multiprocessing is definitely necessary. FastAPI might utilize a separate thread, but that thread still competes for CPU resources with others. My use of "parallel" referred to how requests can be handled in overlapping time periods via threading, even with the GIL. I wanted to avoid mixing the two approaches: executing in separate thread in thread pool and executing concurrently in the main thread event loop.

boooozi txeq

can you make fastapi how run under the hood and how @app.exception_handler work Thanks awesome contentent