Blog Posts

When to use cache and when not to

When to use cache and when not to

There is a production bug that I still remember vividly: user A cancels an order, but the app still displays “delivering” for the next 10 minutes. Support receives 30 tickets in one morning. The reason: cache TTL is 10 minutes, but no one invalidates it when the order status changes.

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API Filtering: retrieving data like a coffee connoisseur

API Filtering: retrieving data like a coffee connoisseur

In my first year of working, I once wrote an endpoint GET /api/menus that returned… the entire menu. 200 items every time it was called. The JSON was 1.2MB heavy. The frontend only needed the name and price of 10 active dishes. I remember the first thing my lead said: “You’re sending the entire warehouse to someone who just needs to view the menu, aren’t you?”

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Context in Go: passing data, deadline, cancel - use correctly or die of performance

Context in Go: passing data, deadline, cancel - use correctly or die of performance

When I first coded in Go, I encountered a strange production bug: after running for 3-4 days, the service suddenly consumed 8GB of RAM and caused an OOM error. I spent the entire Friday afternoon debugging and finally discovered the issue: a goroutine never ended because I forgot to pass the context to the gRPC call. Each request leaked a goroutine, and after 100K requests, the server was overwhelmed.

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