#35853: Disable garbage collection during transaction.atomic.
-------------------------------------+-------------------------------------
Reporter: Matej Spiller Muys | Owner: (none)
Type: New feature | Status: closed
Component: Database layer | Version: 5.1
(models, ORM) |
Severity: Normal | Resolution: wontfix
Keywords: gc, atomic, | Triage Stage:
transaction | Unreviewed
Has patch: 0 | Needs documentation: 0
Needs tests: 0 | Patch needs improvement: 0
Easy pickings: 0 | UI/UX: 0
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Comment (by Natalia Bidart):
Replying to [comment:2 Matej Spiller Muys]:
> The need for having db transactions as short as possible is quite
general rule.
I disagree with this. While I recognize that managing transaction
thresholds and garbage collection may be critical for large-scale
services, such as Instagram, I believe that the average Django project
does not require such measures. Django has been around for nearly 21
years, and this is the first time such a request has been reported in the
issue tracking system. This suggests that the need for disabling GC to
allow lowering the transaction max time is not a common concern among the
broader Django users.
> We are currently having our own atomic decorator that is disabling GC
but I filled the issue because it seems like could be useful for wider
audience. I will write to forum and see if there is more general need for
high performance Django minding DB resources.
Nice, do you have any benchmarks available, following Claude's ask? Please
note that besides needing community consensus, we'd need a clear win on
performance for a change like the one proposed. This is documented in
https://docs.djangoproject.com/en/dev/internals/contributing/bugs-and-
features/#requesting-performance-optimizations.
> Example code that we use:
> {{{
> @contextlib.contextmanager
> def disable_gc():
> _gc_was_enabled = gc.isenabled()
> if _gc_was_enabled:
> gc.disable()
> try:
> yield
> finally:
> if _gc_was_enabled:
> gc.enable()
>
> @contextlib.contextmanager
> def atomic(using=None, savepoint=True, durable=False):
> with disable_gc(), transaction.atomic(using, savepoint, durable):
> yield
> }}}
I believe this code is not thread-safe nor reentrant-safe. For a proposal
like this to be considered for inclusion in the core framework, we would
need strong guarantees that it meets these criteria and that garbage
collection is not inadvertently "disabled forever" due to unforeseen bugs.
While the need for this functionality is valid and presents an interesting
challenge, I reiterate that this is a niche use case, perhaps relevant to
only 1% or even 0.5% of Django services deployed in the wild. As
previously mentioned, Django aims to provide a robust, stable, and secure
platform for common web service requirements, and this particular need
feels outside the realm of what is considered "common."
--
Ticket URL: <https://code.djangoproject.com/ticket/35853#comment:4>
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