MySQL : getting the most intensive/called/slow requests


With MySQL (the community edition I guess, the one packaged in Debian and many other distros I think), what (free) tool do I have to check the performance?
I'd like to be able to get the most disk intensive requests, the ones reading too many lines, the requests called too many times (let say, a lot of times), that kind of top-tens. My goal is to highlight some bad requests and algorithms we've probably written in our application.
This way, we'll change some programs, create indexes where we need and so on...

I found some commercial tools (I don't remember the company name right now), but I don't think they're free.

In comparison with Oracle, I know I have all the information inside the database, and I can extract it. I don't think it's the same with MySQL

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Some of that can be accomplished by using the slow query log, see
mchkorgAuthor Commented:
OK, I'll tell our "partner" [supposed to be] managing our database to tell them to activate it.
But I'd prefer to give them every configuration modification at the same time.

So, any other idea? (including or not an optional DB reconfiguration)
Have the slow query log enabled first, then after at least one busy day (more would likely be better), ask for a copy.  Tune your queries and add indexes based on that.  Better if you have that covered before you move to server tuning.  After you've performed that, wait another few days, then ask for  the following:

1.  Copy of the slow query log
2.  Copy of my.cnf
3.  Output of "show variables" (this is just in case somebody put some setting that overrides that of my.cnf)
4.  Output of "show global status"

The combination of the above will help you formulate what configuration settings need to be changed.
mchkorgAuthor Commented:
Thank you, with this, I have tons of awful requests to give to the development team.
I'm closing this question now as I don't event need further analysis right now. I'll check my.cnf and other variables later, when those awful requests and algorithms are corrected.
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