How does the query cache work in MySQL?
The query cache stores the text of a SELECT statement together with the corresponding result that was sent to the client. If an identical statement is received later, the server retrieves the results from the query cache rather than parsing and executing the statement again.
How to defragment the query cache in MySQL?
You can defragment the query cache to better utilize its memory with the FLUSH QUERY CACHE statement. The statement does not remove any queries from the cache. The RESET QUERY CACHE statement removes all query results from the query cache.
What are the select options for Query Cache?
Two query cache-related options may be specified in SELECT statements: SQL_CACHE. The query result is cached if it is cacheable and the value of the query_cache_type system variable is ON or DEMAND. SQL_NO_CACHE. The server does not use the query cache.
How to check if a query result is cached?
Two query cache-related options may be specified in SELECT statements: SQL_CACHE. The query result is cached if it is cacheable and the value of the query_cache_type system variable is ON or DEMAND . SQL_NO_CACHE. The server does not use the query cache. It neither checks the query cache to see whether the result is already cached,
The query cache also works within transactions when using InnoDB tables. The result from a SELECT query on a view is cached. The query cache works for SELECT SQL_CALC_FOUND_ROWS queries and stores a value that is returned by a following SELECT FOUND_ROWS () query.
How to limit the size of the cache in MySQL?
If you set query_cache_type at server startup (rather than at runtime with a SET statement), only the numeric values are permitted. To control the maximum size of individual query results that can be cached, set the query_cache_limit system variable. The default value is 1MB.