Feature request: queryset caching inside a request

Has anyone else ever been surprised by the number of duplicate
database queries when looking at the Django debug toolbar output?

In my application, we have models for Users, Profiles and Companies.
Many of our methods take a user as a parameter, and then look up the
related profile and/or company. It's very common for a single page
request to end up performing the same profile or company query a dozen
times.

Of course, the code could be refactored to pass these objects around
as needed instead of looking them up again. In fact, I have already
started using a middleware that populates these as attributes on the
request object. But it got me thinking, is this a common pattern among
Django apps? If so, I wanted to propose a solution.

What if by default query sets were cached for the duration of that
request? For example, you could perform a User.objects.get(id=123)
twice inside a single request/response cycle, and the second time it
would be retrieved from a per-request cache in memory.

Obviously this could break existing code, so it would need to be
optional. But I would think that in almost all cases, web applications
behave consistently with this enabled. In the cases where you really
do want a fresh query, there could be a new chained query set method
like .refresh() or .live().

I'm interested on other people's estimates of how many database
queries this would save them on their real world projects. I'm
estimating 20% for mine.

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