question and potential consulting gig

we are looking to enhance our projects search.  we only need searching  
of database tables.  we are currently using postgresql's full text  
search.

from your experience, how long does xapian index take to add delta's  
to results?  on your site you advertise "Allows simultaneous update  
and searching. New documents become searchable right away."  what does  
right away mean?  like less than a minute, 5 minutes (given unlimited  
hardware resources)?  is there db size where adding delta's is slow?

if someone can confirm this, i would like to discuss a potential  
consulting job with them.

cheers,

Kyle J. Ginavan