Reducing memory consumption

[gluhar2006]

I have found that the more requests Sanic processes, the more memory consumption increases. This behavior, as far as I could understand, is relevant only with a sufficiently large number of requests.
After some research, I took an idea from here to make sure that no unnecessary objects remain in memory after processing requests.

Application I used

import gc
import tracemalloc

from sanic import Sanic
from sanic.response import text
import psutil
import os

tracemalloc.start()


app = Sanic("MyHelloWorldApp")
request_cnt = 0

def mem_top():
  gc.collect()
  objs = gc.get_objects()

  return "\n".join((
      '',
      _top(10, 100, "\n", "{num} {obj}", (
          (len(gc.get_referents(obj)), obj) for obj in objs
      )),
  ))


def _top(limit, width, sep, fmt, nums_and_objs):
  return sep.join(
      fmt.format(num=num, type=type(obj), obj=repr(obj)[:width])
      for num, obj in sorted(nums_and_objs, key=lambda num_obj: -num_obj[0])[:limit]
  )


@app.post("/")
async def hello_world(request):
  global request_cnt
  request_cnt += 1
  print(round(psutil.Process(os.getpid()).memory_info().rss / 2 ** 30, 6))
  if request_cnt == 10000:
      print(str(mem_top()))
  return text("qq")


if __name__ == "__main__":
  app.run(port=5021)

I used ab to make requests

(it doesn't matter what's in the request body)

  ab -p data -T "application/x-www-form-urlencoded" -c 50 -n 10000 "http://0.0.0.0:5021/"

So i discovered thousands of TimerHandle HttpProtocol.check_timeouts and abort from SanicProtocol (required much more than 10000 requests).

My changes solves the memory freeing question, but it also has another side effect: here is rps from ab results before and after my changed - 7273 (main branch) vs 8558 (this branch).
Yes, I know that this is not the most relevant way to measure performance using such requests, but I don't have time to properly test the framework. I can only say that the applications that I develop and use Sanic at least did not slow down after my changes.

[codecov]

Codecov Report

Attention: 4 lines in your changes are missing coverage. Please review.

Comparison is base (d1fc867) 88.414% compared to head (6771fac) 88.362%.

Files	Patch %	Lines
sanic/server/protocols/http_protocol.py	66.666%	2 Missing and 2 partials ⚠️

Additional details and impacted files

@@              Coverage Diff              @@
##              main     #2831       +/-   ##
=============================================
- Coverage   88.414%   88.362%   -0.052%     
=============================================
  Files           92        92               
  Lines         7164      7175       +11     
  Branches      1229      1232        +3     
=============================================
+ Hits          6334      6340        +6     
- Misses         575       580        +5     
  Partials       255       255               

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[Tronic]

Should also look at clearing cyclic links once done with request/connection, so that Sanic itself would not leak memory when used without GC. Some of them are already cleared but surely some loops remain too.

[gluhar2006]

@Tronic I didn't find any other issues of such type or memory leaks

[Tronic]

@Tronic I didn't find any other issues of such type or memory leaks

But you still had GC enabled? Sanic takes care to clear to avoid cyclic links but I am sure it ain't 100 % yet. This is only relevant once GC is disabled.

[gluhar2006]

@Tronic

But you still had GC enabled? Sanic takes care to clear to avoid cyclic links but I am sure it ain't 100 % yet. This is only relevant once GC is disabled.

Yes, GC is enabled. I don't think that the basic recommendation of sanic usage is to disable GC

[Tronic]

@Tronic

But you still had GC enabled? Sanic takes care to clear to avoid cyclic links but I am sure it ain't 100 % yet. This is only relevant once GC is disabled.

Yes, GC is enabled. I don't think that the basic recommendation of sanic usage is to disable GC

Definitely not a basic recommendation. It takes a lot of care to avoid/break cycles in all code, user apps included. But for maximal performance you would want it disabled, can make quite a difference at times.

[gluhar2006]

@Tronic

But you still had GC enabled? Sanic takes care to clear to avoid cyclic links but I am sure it ain't 100 % yet. This is only relevant once GC is disabled.

Yes, GC is enabled. I don't think that the basic recommendation of sanic usage is to disable GC

Definitely not a basic recommendation. It takes a lot of care to avoid/break cycles in all code, user apps included. But for maximal performance you would want it disabled, can make quite a difference at times.

Memory consumption with disabled gc is low and stable