I Spent 3 Weeks Fighting Embedded Database Lockups — Here's What I Learned

Last month, I was debugging a weird issue on a Raspberry Pi 4. Our robot would randomly freeze for 2-3 seconds every few minutes. No error messages. No crashes. Just. pauses. After three weeks of printf debugging (yes, I'm that person), I finally found the culprit: our embedded database was doing a full WAL checkpoint on the main thread.