The whole idea of locks is to restrict access to objects or records to avoid conflicting operations to concurrently access the object or records in a safe way. That means that, sometimes, a lock cannot be granted. What happens in that case? It depends on the locks requested and the circumstances. Metadata (including explicitly requested table locks) and InnoDB locks operate with a timeout, and for some lock cases explicit deadlock detection exist.
It is important to understand that failures to obtain locks are a fact of life when working with databases. In principle you ...
