Many people would dearly love to switch from windows to linux but circumstances prevent them from doing so. Similarly many people would stop using mysql and switch to postgresql if not for the strings that hold them back.
I fall into this latter category and though I have postgres installed on my computer and use it for lots of things, I found myself upgrading the mysql installation, which had gone quite stale.
The last few times I installed mysql I used binary downloads but this time around decided to compile from source. As in some earlier versions the documentation suggests that you pass in some optimization parameters to GCC so that you can get better performance out of mysql.
I have no faith in these compiler options being able to boost the speed of applications but decided to put it to the test just to see if there is any truth in it. The first first time around mysql was compiled with out any optimizations and then I ran a rather expensive subquery. Next mysql was compiled with the following compiler options:
-O3 -mtune=pentium4 -march=pentium4
Is there an increase in speed? no. The query takes about 2 minutes regardless of the compiler options.