Stop replying to posts without knowledge and sense

Railway's status page shows all systems fully operational right now, so this isn't a broad platform-wide outage — status.railway.com currently reports Railway as fully operational. That points to something specific to your instance rather than a global incident. A few things worth knowing:

A known pattern: Railway Metal migration

There's a documented case on Railway's own support forum matching your symptoms almost exactly — a user reported that after upgrading their MySQL instance to Railway Metal, round-trip times jumped from under 500ms to 1.3–2 seconds with no errors in the logs, and network latency from app to database stayed persistently elevated. In that case, the person only got relief by creating a fresh instance and deleting the old one. If your project has been migrated (or auto-migrated) to Railway Metal, this is a strong suspect — worth checking your project settings/region to see if that's happened, especially since you mentioned some services showing on "legacy regions" in that thread too.

Other likely causes for the on/off pattern:

• Resource plan limits — Railway's shared/hobby plans throttle CPU or I/O when you hit plan limits, which produces exactly this "fine, then degraded for days, then fine" pattern as usage fluctuates.
• Region mismatch — if your app and database are deployed in different regions, every query pays a geographic latency tax over Railway's network, and this can get worse under load.
• Public vs private networking — if services in the same project are talking over the public internet instead of Railway's private network, that adds unnecessary latency, and public network paths are more subject to noisy-neighbor congestion than private ones.
• "Noisy neighbor" on shared infrastructure — on non-dedicated plans, another tenant's load on the same host can degrade your DB unpredictably, independent of your own queries.

What I'd check right now, in order:

1. In your Railway MySQL service, check whether it's on Railway Metal and what region it's in vs. your app service — mismatches or recent migrations are the top suspect.
2. Check your plan's resource metrics (CPU/memory/disk I/O graphs) for the exact window when things slow down — if you're pegging a limit, that confirms throttling.
3. Confirm your app connects via the private network URL, not the public one.
4. Run 'SHOW FULL PROCESS LIST' during a slow period to see if it's actual query contention (locks, long-running queries) vs. pure network/infra latency.