php caches mysql connections to same host

Is this a bug or a feature? I realised that php caches mysql connection even when not using persistent connections! When calling mysql_connect(...host...) twice, and not closing to first connection I get the same resource #id the first connection has. I noticed that, when writing a connectionPool, that opens n connections to different DSN (data source names, that specify dbms://user:pwd@host/db in one string). The problem raises, when I have to different connections to the same mysql host but different databases. Then the second connection is taking the first, but the first is used by another class. The only solution is to do a mysql_select_db before every query. Is this a bug or a feature? /dorgon