> I've got a large multi-user PHP app that uses mysql_connect() throughout,
> and would like to convert to mysql_pconnect(). Is it enough simply to
> change every instance of one to the other,
> or must care be taken, for
> example, not to have two pconnect calls within the same script (to avoid
> spawning unnecessary processes with each call)?
No; mysql_pconnect() is smart enough to re-use an existing
connection if one is available.
> Finally, if mysql_pconnect() is so much better on overhead than
> mysql_connect(), why wouldn't I always use it? Put another way, is there
> any reason _not_ to use it?
I use it extensively in a variety of high-traffic websites.
I know of no reason to use mysql_connect rather than _pconnect.