Hello,
TPS (transactions per seconds) are a term for marketing of the big database companies.
95% of the proper designed applications don't need really transactions..
Considerations about performance are depending on the coming load : #users , #requests
Common issues are heavy to describe in the short. But for simple database-tasks on websites, the apache/php/Mysql (LAMP/WAMP)
is the popularest and a sufficient solution.
A PHP-Cache and a Zend-Optimizer are doing their work well.
Under 50 users working on a modern PC-server (ca. 1 GHz) you wouldn't get any bottlenecks....
If youre'nt satisfied with this answer, don't hesitate to ask more and put more infos on your environment.
Regards
Ingo