Thanks for contributions. Really I was going to use large switches, both as associative arrays and as sets. I hoped, that algorithm was based simply on string search into the code (I presume, it is possible, and I know how efficient is plain string search in any decent language) but I guess, from your replies, that I was wrong. :-(
I'll use strictly the 2000 items limit; I presume that - in occasional cases - I will be forced to split larger switches into different containers, after some string manipulation with padleft trick.
Well, it's hyronical that wiki is based on a powerful database, while user interface forces contributors to use any kind of dirty trick to simulate basic, extremely simple database-like jobs ..... :-(
Alex