nginx could not build the server_names_hash hash

When restarting nginx, suddenly I came accross this error message:

could not build the server_names_hash hash, you should increase server_names_hash_bucket_size: 32

Now, that's solved pretty easily - by increasing server_names_hash_bucket in config file to a bigger value. According to author, Igor Sysoev, even p4 can easily handle value of a 128.

So I put
server_names_hash_bucket_size 128;
in nginx.conf, and everything works fine.