Do Rails sql query cache hit database?

Question

In my Rails application I see a few 'cache' during SQL query in the server log:

[DEBUG] CACHE (0.0ms) SELECT regions.* FROM regions WHERE regions.name = 'NY' LIMIT 1

I want to know if these caching are done by Rails, or by the MySQL itself? In another word, do these cached queries touch the database layer at all?

@hlcs I don't know why the chosen answer got downvoted? Clearly it says the same thing as the other answer no? — lulalala
@lulalaIa accepted answer says how to bypass chaching. The question is: do these cached queries touch the database. — hlcs
@hlcs I guess chosen answer implies the "no" answer, provided with reference evidence which I felt more trustworthy. — lulalala

Tom Harrison Tom Harrison · Accepted Answer · 2013-10-17T02:32:55

The correct answer to the question is "the caching is done by Rails; the queries do not ever get to the database".