How a Deadlock Froze Blinkit’s Supply Chain

Blinkit's inventory replenishment pipeline froze silently — no errors, no crashes, just queries stuck indefinitely. The root cause was a deadlock in Trino's Hudi connector: producer threads filling a split buffer would block waiting for consumers to drain it, but consumers needed threads from the same shared pool that producers were holding. The fix replaced blocking with a cooperative yield pattern — producers hand the thread back to the pool and register a callback to resume when space opens, breaking the circular dependency. The bug was confirmed in Trino v455 and master, and a fix was contributed upstream.