Wallet transfers fail intermittently
After a deploy this afternoon, the wallet/ledger service starts logging a flood of "deadlock detected" errors — hundreds per minute, up from ~zero. The DB auto-aborts one transaction in each cycle, so users see intermittent "transaction failed, please retry" on transfers, and the retry logic causes a thundering retry storm that makes it worse. The deadlock graph in the logs shows two transactions each updating two `accounts` rows: one does `UPDATE account A then B`, the other `UPDATE account B then A`. The deploy changed the transfer code path. CPU is moderate; throughput is down because so much work is being rolled back. Triage and mitigate.
Stop the bleeding first (mitigate), then form hypotheses from real signals. Separate root cause from symptom, communicate status as you go, and close with what prevents a repeat.