Use an atomic counter for datastore reads in Check

[miparnisari]

Checklist

• I agree to the terms within the OpenFGA Code of Conduct.

Describe the problem you'd like to have solved

Original discussion: #1452 (comment)

The code that calculates how many database reads were accrued in Check is hard to follow and is error-prone.

Describe the ideal solution

The proposed solution is to use an atomic.uint32 counter for the datastore_query_count, similar to dispatch_counter (

openfga/internal/graph/graph.go

Line 58 in b6f3d4a

DispatchCounter *atomic.Uint32

)

Pros:

• more readable code

Cons:

• we are introducing a mutex, which introduces slight delays in the API
• goes against the future idea of introducing remote peer dispatching, because we can't share an atomic counter across nodes.

Alternatives and current workarounds

No response

Additional context

No response