Remember that the locking in MySQL and InnoDB is a means to provide concurrent access, and in general the fine-grained locking of InnoDB allows for a highly concurrent workload. Yet, if you have excessive locking, it will cause reduced concurrency and query pileups, and in the worst case, it can cause an application to come to a grinding halt and cause a poor user experience.
Thus, it is important to have locks in mind when you write an application and design the schema for its data and access. The strategies to reduce locking include adding indexes, changing the transaction ...
