#concept/invariants 3
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- Seedling 7 months ago
Memory models: the rules behind happens-before
Single-threaded code runs in the order you wrote it. Put a second thread on the same memory and that stops being true - a memory model is the contract for which writes a thread is guaranteed to see, and when.
- Evergreen last year
Rate limiting as an invariant
A rate limit reads like a restriction from outside and like a promise from inside - the invariant that keeps a system in a regime where it still works.
- Seedling last year
Retries and idempotency
Retries are only safe when the operation is idempotent - otherwise you get duplicate records or double charges.