Re: MySQL on an SMP system - exploiting it

bit-naughty_at_hotmail.com wrote:

> Guys... what I'm asking is, if I add in another chip, will it increase the
> performance of my server - it's a simple question really...?

The question may be simple, but the answer is /not/. An answer on par with you question would be: "It depends."; however, MySQL does support multi-core processing (MySQL FAQ question A.1.8. "Does MySQL 5.7 work with multi-core processors?", answer: "Yes. MySQL is fully multi-threaded, and will make use of multiple CPUs, provided that the operating system supports them. "

> (MySQL and
> other things included, but naturally, in THIS group, it's MySQL I'm
> concerned about!). I mean, why else would someone purchase an SMP system??
> Right?

Not necessarily. But that's a discussion for another day and another newsgroup.

> When MySQL goes to do a SELECT, can it TELL that the core it's trying to
> do it on is overloaded, and switch to a different core? - I guess that's
> the question I'm trying to ask.....

And, that's a question that will be difficult to get an answer for here.

The best you will likely get here (absent of inspection of the MySQL implementation code) is that MySQL "is fully multi-threaded, and make use of multiple CPUs". Whether or not SELECTs are run as threads, and are elegible for execution on independant CPUs is a question that can only be answered by someone with intimate knowledge of the internals of the specific MySQL implementation you are running.

-- 
Lew Pitcher
"In Skills, We Trust"
PGP public key available upon request