this has been brought up before, and IIRC Skuzzy mentioned the problem inherent with having 3 character searching the database.
database queries can get really complicated, and I personally don't know enough about them, but I do know it is an issue of the search, and the size of the cache.
in the past there were problems with the scoring database, multiple searches taking enormous processing powers, and it messed with the arenas. why? the arenas have to send data to the scoring database, and if the arena server can't send that data it messes it up.
here on the board in the past there were times multiple searches took so much processing power that the board crashed.
I do know it's not about "getting a more powerful server"
At work I manage a database server that is not "huge" it has about 150GB of image data, but with a xeon processor, 3GB ram, and a gigabyte connection it still can take up to 20 seconds for some queries.
the software powering the board is another issue. if the software were to allow "cached" searches like "la7" "b29" or whatever maybe they could implement those, but I don't think the software has that capability.
now I could be completely wrong on this, but I do remember Skuzzy mentioning the database issues 1 time when the search character limit was pushed up to 4 characters.
Skuzzy if you could let me / them know if I am close to correct on this, thanks.