[Zope] Performance Hit

[beno]

Hi;
I want to call parts of the "pages" Zope serves from a MySQL database. My 
programmer tells me there would be a performance hit. I have a hard time 
understanding why (or if there is, I think it would be small). After all, 
Zope itself calls everything from a database (ZODB) and all of this 
activity would be server-side. There will be nothing complicated in the 
call: four simultaneous calls per page served. Is this problematic?
TIA,
beno