Why the keep_fresh parameter in cached_as does not default to True ?

Suor / django-cacheops

A slick ORM cache with automatic granular event-driven invalidation.

BSD 3-Clause "New" or "Revised" License

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Why the keep_fresh parameter in cached_as does not default to True ? #424

Closed nMustaki closed 2 years ago

nMustaki commented 2 years ago

Hello Suor,

first thanks for your work, it's very helpful here ! I'd like to ask some help to understand why the keep_fresh parameter of cached_as does not default to True ? Why would we want to cache stale data ? Thanks !

Suor commented 2 years ago

In short:

it costs to recheck
if we do not cache while concurrent invalidation is happening we may never cache if we are under heavy invalidation
if there are lots of invalidations stale cache won't survive long anyway

Sometimes not caching will mean app will just hang up, which is worse than serving something stale.

You can take a look at original PR too https://github.com/Suor/django-cacheops/pull/302

nMustaki commented 2 years ago

Thanks you, that's a lot clearer !