Poor performance when loading huge number of server section

[Anb]

Hi there,
  I got a problem when using nginx as a reverse proxy. Configurations
using per server policy to set upstream host. Nginx spends significant
time loading config files as while as virtual server inscreased to a
large number. Here's a rough statistics:

| server sections | load time(sec) |
|-----------------+----------------|
|           50000 |            242 |
|           80000 |            910 |
|          100000 |           1764 |

I know this is an unusual usage of nginx, but there is such demand.

So I want to know:
1. Is nginx not designed to use such large number of config?
2. Does someone has some experience on this? Could you please show me a clue?

Thanks.

-- 
anb
2013.8.9