checking privileges on cached query

The server is checking whether the user has privileges to access a cached query result.

checking query cache for query

The server is checking whether the current query is present in the query cache.

invalidating query cache entries

Query cache entries are being marked invalid because the underlying tables have changed.

sending cached result to client

The server is taking the result of a query from the query cache and sending it to the client.

storing result in query cache

The server is storing the result of a query in the query cache.

Waiting for query cache lock

This state occurs while a session is waiting to take the query cache lock. This can happen for any statement that needs to perform some query cache operation, such as an INSERT or DELETE that invalidates the query cache, a SELECT that looks for a cached entry, RESET QUERY CACHE, and so forth.