[PERFORM] numerical primary key vs alphanumerical primary key

[Anne Rosset]

Hi,
I have read a lot of different information about the benefits of using 
numerical primary key vs alphanumerical primary key(small size). And what I am 
gathering is that for performance there is no more great advantage.
It seems like now RDBMS in general, postgres in particular handles pretty well 
joins on text indexes.
Did I understand correctly?
Thanks,
Anne