[racket] confusion on virtual-connection

On 04/11/2013 04:27 PM, Kejia柯嘉 wrote:
> hi all,
>
> if i use `virtual-connection' from a `connection-pool' to get a
> connection, is the connection disconnected or released back to the pool
> when the thread involved finishes?

It's usually released back to the pool. There are some situations that 
cause it to be disconnected instead, such as if the connection is in a 
transaction when the thread finishes (if I recall correctly).

> p.s.: when i use `connection-pool', why is there no change of the number
> of active connections in psql (select * from pg_stat_activity;)?

The pool creates a few connections and reuses them, so the number of 
active connections should not change (or rather, it should change slowly).

Ryan