Quote
if we run simple query "select * from tablename;" and got slow response ...
Of course you're going to get a slow response.
Imagine you have a physical copy of the MySQL reference manual.
"select * from ..." means go and read
every single page of that book and returned absolutely everything it contains.
The
only way to "tune" this is to throw hardware are it - faster disks, faster memory, faster processors.
My question would be - does it even
matter that this query is slow?
Really. In all likelihood, your application is
never going to run this query as is!
When do you reach for "The Manual" (or Google)?
When you're looking for something
specific.
How do you find it?
You go to the back, to the "Index", and there you scan through the entries to find the thing you want, say, "create user". Then, you use the page number(s) in the Index to go into the body of the book, to find the details of what you need.
MySQL does pretty much the same thing.
You're
far more likely to run a query like this:
select x, y, z
from table1
where keyfield = 'value';
To do that efficiently, MySQL works out how
best to get to that data. If
that turns out to be slow, then you
can improve things
within the database, using indexes and the like.
Regards, Phill W.