Mysql memory engine cache and file cache, which is more efficient

Mysql memory engine cache and file cache, which is more efficient session?

Data is stored by file hard disk by default. ---> hard disk
Change to mysql memory engine storage ----> Memory

Regardless of other factors, which of the two solutions is faster?

Hard disk <memory;
File> mysql;

What is the final result ?! Special request.

Reply to discussion (solution)

The latter!
In this case, you will know the actual comparison.

Static file cache is definitely more efficient .. The actual usage depends on the specific situation, and sometimes the memory cache is good.

I am also curious, static pages, the whole page is cached to the server, the data is read through the TXT existing server, and read from the database. What is the speed sorting of these four methods?

No comparability

1. the static page is directly returned by the server without php processing.
2. the entire page is cached on the server and is only read and output by php (no other action)
3. store the TXT file on the server for further reading and reading from the database.
Both methods require php to read and analyze and process data.
The database table is also a file
So the two are equivalent

Understand .....