MySQL Troubleshoting: Waiting on query cache mutex

MySQL Troubleshoting: Waiting on query cache mutex was cached by MySQL Query Cache today. There are a large number of online Waiting on query cache mutex. So what is Query Cache? QC caches the result set of the entire SELECT, rather than the execution plan. The principle of QC is as follows: the fastest way to execute a query is not to execute the query. However, QC's simple and crude failure policy, which makes it easy to execute any difference (space, TAB indentation, DML, etc) this will cause the Cache of the table to become unavailable. It is controlled by single mutex. How can we disable QC in case of severe lock competition? Control two parameters: ① query_cache_type = off ② query_cache_size = 0 overall, QC is not recommended, chicken ribs function, "chicken ribs, abandon is a pity, nothing to eat ", resulting in dozens of hundreds of times of performance differences if there is indeed this cache demand, where the application permits, high availability Redis or MC and other alternatives